Contaminated Runways

CONTAMINATED RUNWAY − A runway is considered contaminated whenever standing water, ice, snow, slush, frost in any form, heavy rubber, or other substances are present. A runway is contaminated with respect to rubber deposits or other friction-degrading substances when the average friction value for any 500-foot segment of the runway within the ALD fails below the recommended minimum friction level and the average friction value in the adjacent 500-foot segments falls below the maintenance planning friction level.

Source: Aeronautical Information Manual, Pilot/Controller Glossary

The standard dry runway charts are for a totally dry runway. NOTE: For example, if the ramp is too damp to sit on due to morning dew, the runway is probably the same. The pilot should use the wet or contaminated performance data.

Source: AC 91-79A, App. 3, ¶5.

Runway Condition Code (RwyCC). Runway Condition Codes describe runway conditions based on defined contaminants for each runway third. Use of RwyCCs harmonizes with ICAO Annex 14, providing a standardized “shorthand” format (e.g., 4/3/2) for reporting. RwyCCs are used by pilots to conduct landing performance assessments.

Source: AC 150/5200-30D, ¶1.12.17

FICON (Field Condition Report). A FICON is a Notice to Airmen (NOTAM) generated to reflect pavement surface conditions on runways, taxiways, and aprons and Runway Condition Codes (RwyCCs) if greater than 25 percent of the overall runway length and width coverage or cleared width of the runway is contaminated.

Source: AC 150/5200-30D, ¶1.12.8

Contaminated Runway. For purposes of generating a runway condition code and airplane performance, a runway is considered contaminated when more than 25 percent of the overall runway length and width coverage or cleared width is covered by frost, ice, or any depth of snow, slush, or water.

Source: AC 150/5200-30D, ¶1.12.4

Dry Runway/Pavement. Use the term “DRY” to describe runway/pavement surfaces that are neither wet nor contaminated. A FICON NOTAM must not be originated for the sole purpose of reporting a dry runway. A dry runway surface should be reported only when there is need to report conditions on the remainder of the surface.

Source: AC 150/5200-30D, ¶1.12.5

Wet Runway. A runway is wet when it is neither dry nor contaminated. For purposes of condition reporting and airplane performance, a runway can be considered wet when more than 25 percent of the overall runway length and width coverage or cleared width being used is covered by any visible dampness or water that is 1/8-inch (3 mm) or less in depth.

Source: AC 150/5200-30D, ¶1.12.23

Dry Snow. Dry snow is snow that has insufficient free water to cause it to stick together. This generally occurs at temperatures well below 32° F (0° C). If when making a snowball, it falls apart, the snow is considered dry.

Source: AC 150/5200-30D, ¶1.12.6

Wet Snow. Wet snow is snow that has grains coated with liquid water, which bonds the mass together, but that has no excess water in the pore spaces. A well-compacted, solid snowball can be made, but water will not squeeze out.

Source: AC 150/5200-30D, ¶1.12.24

Slush. Slush is snow that has water content exceeding a freely drained condition such that it takes on fluid properties (e.g., flowing and splashing). Water will drain from slush when a handful is picked up. This type of water-saturated snow will be displaced with a splatter by a heel and toe slap-down motion against the ground.

Source: AC 150/5200-30D, ¶1.12.20

Water. Water is the liquid state of water. For purposes of condition reporting and airplane performance, water is greater than 1/8-inch (3mm) in depth.

Source: AC 150/5200-30D, ¶1.12.21

Ice. Ice is the solid form of frozen water including ice that is textured (i.e., rough or scarified ice). Note: A layer of ice over compacted snow must be reported as ice only.

Source: AC 150/5200-30D, ¶1.12.10

Wet Ice. Wet ice is ice that is melting, or ice with a layer of water (any depth) on top.

Source: AC 150/5200-30D, ¶1.12.22

1. Contaminated runway. A runway is contaminated when more than 25 per cent of the runway surface area (whether in isolated areas or not) within the required length and width being used is covered by:
• water, or slush more than 3 mm (0.125 in) deep;
• loose snow more than 20 mm (0.75 in) deep; or
• compacted snow or ice, including wet ice.
2. Dry runway. A dry runway is one which is clear of contaminants and visible moisture within the required length and the width being used.
3. Wet runway. A runway that is neither dry nor contaminated.

Note 1.— In certain situations, it may be appropriate to consider the runway contaminated even when it does not meet the above definition. For example, if less than 25 per cent of the runway surface area is covered with water, slush, snow or ice, but it is located where rotation or lift-off will occur, or during the high speed part of the take-off roll, the effect will be far more significant than if it were encountered early in take-off while at low speed. In this situation, the runway should be considered to be contaminated.

Note 2.— Similarly, a runway that is dry in the area where braking would occur during a high speed rejected take-off, but damp or wet (without measurable water depth) in the area where acceleration would occur, may be considered to be dry for computing take-off performance. For example, if the first 25 per cent of the runway was damp, but the remaining runway length was dry, the runway would be wet using the definitions above. However, since a wet runway does not affect acceleration, and the braking portion of a rejected take-off would take place on a dry surface, it would be appropriate to use dry runway take-off performance.

Source: ICAO Annex 6, Part 1, Att B, Page B-2

• "Contaminated runway". A runway is considered to be contaminated when more than 25 % of the runway surface area (whether in isolated areas or not) within the required length and width being used is covered by the following:
1. surface water more than 3 mm (0,125 in) deep, or by slush, or loose snow, equivalent to more than 3 mm (0,125 in) of water;
2. snow which has been compressed into a solid mass which resists further compression and will hold together or break into lumps if picked up (compacted snow); or
3. ice, including wet ice.
• "Damp runway". A runway is considered damp when the surface is not dry, but when the moisture on it does not give it a shiny appearance.
• "Dry runway". A dry runway is one which is neither wet nor contaminated, and includes those paved runways which have been specially prepared with grooves or porous pavement and maintained to retain "effectively dry" braking action even when moisture is present.

Source: EASA Air Ops Annex 1 to VIII, §ANNEX 1

• "Wet runway." A runway is considered wet when the runway surface is covered with water, or equivalent, less than specified in subparagraph (a)(2) above or when there is sufficient moisture on the runway surface to cause it to appear reflective, but without significant areas of standing water.

Source: EASA Air Ops Annex 1 to VIII, §ANNEX 1

1. RUNWAY CONTAMINATED BY STANDING WATER, SLUSH OR LOOSE SNOW
   A runway is considered to be contaminated, when more than 25% of the runway surface area (whether in isolated areas or not), within the required length and width being used, is covered by more than 3 millimeters (1/8 inch) of standing water or its equivalent in slush or loose snow (see table below):

STANDING WATER	SLUSH	LOOSE WET SNOW	LOOSE DRY SNOW
3.2 mm (0.125 in)	3.8 mm (0.15 in)	7.6 mm (0.30 in)	15.2 mm (0.60 in)
6.4 mm (0.25 in)	7.6 mm (0.30 in)	15.2 mm (0.60 in)	30.5 mm (1.2 in)



2. RUNWAY CONTAMINATED BY COMPACTED SNOW
   A runway is considered to be contaminated by compacted snow when covered by snow which has been compacted into a solid mass which resists further compression and will hold together or break into lumps if picked up.
3. RUNWAY CONTAMINATED BY ICE
   A runway surface condition where braking action is expected to be very low, due to the presence of ice.

Source: Bombardier BD-700 Airplane Flight Manual, §07-03-01-1, ¶1.B.

• Dry runway: A runway is considered dry if it is clear of visible moisture. A damp runway, which has a moisture layer that is nonreflective, is also considered dry.
• Wet runway: A runway is considered to be wet when there is sufficient moisture to cause it to appear reflective but the depth of the water is not more than 3 mm (0.125 in.).
• Contaminated runway: A runway surface is considered contaminated when more than 25% of the runway surface area is covered with standing water, slush, loose snow (dry or wet), compacted snow or ice.
• Standing water: Water depth is greater than 3 mm (.125 in).
• Slush: Partly melted snow or ice with a high water content, from which water can readily flow.
• Compacted snow: Snow which has been compressed into a solid mass such that the airplane wheels will run on the surface without causing significant rutting.
• Loose snow: Snow on the runway surface which had not been compressed by vehicle or aircraft traffic. Loose snow can consist of either dry snow or wet snow.
• Dry loose snow: Fresh snow that can be blown, or, if compressed by hand, will fall apart upon release.
• Wet loose snow: Snow that will stick together when compressed, but will not readily allow water to flow from it when squeezed
• Ice: Water which has frozen on the runway surface, including the condition where compacted snow transitions to a polished ice surface.

Source: Gulfstream G450 Operational Information Supplement, G450-OIS-02, Section A.

• The μ_B [wheel braking coefficient] deficit observed in the events considered in this paper makes the stopping performance of the airplanes involved more consistent with AFM landing distances for runways contaminated with standing water, than for runways that are merely “wet.” For this reason, observers may be (understandably) quick to conclude that the runways involved must be more contaminated (contain a greater depth of water) than assumed in the wet runway models underlying the AFM distances. However, examination of the runways involved, including an examination of their macrotexture and cross-slope, do not support a conclusion that the runways could have been flooded given the rainfall rates during the events in question. Furthermore, the μ_B actually achieved in a number of these events is consistent with the NASA CFME model for a wet – not flooded – runway. In other words, the NASA CFME model for a wet runway is more conservative than those underlying the airplane AFMs, and moreover, matches the actual airplane performance achieved during the events better than those underlying the AFMs.

Source: Callaghan, §VIII, ¶A.

• The FAA has recognized the reality of this μ_B deficit, and the need to address it, in several documents and actions. SAFO 15009 warns operators that “the advisory data for wet runway landings may not provide a safe stopping margin under all conditions,” and advises them to assume “a braking action of medium or fair when computing time-of-arrival landing performance or [increase] the factor applied to the wet runway time-of-arrival landing performance data.” Moreover, the Transport Airplane Performance and Handling Characteristics ARAC was given a new task to address “wet runway stopping performance.”

Source: Callaghan, §VIII, ¶A.

• In addition, AC 25-32, Landing Performance Data for Time-of-Arrival Landing Performance Assessments, incorporates many of the recommendations of the TALPA ARC, including the RCAM. However, wet (not flooded) runways can either be classified as RCAM code 5 (associated with μ_B levels defined by the §25.109(c) model), or as RCAM code 3 “slippery when wet” (for which μ_B = 0.16 constant). The “slippery when wet” designation applies when the average CFME μ of the runway falls below the AC 150/5320-12C MIN LEVEL – a condition that only one of the runways examined in this paper met. The actual μ_B levels achieved on the other runways was between those specified by RCAM codes 5 and 3. Consequently, the RCAM as currently specified in Ref. 32 will likely overestimate the μ_B that can actually be achieved on operational, wet runways.

Source: Callaghan, §VIII, ¶A.

• Airport operations on wet loose snow and slush-covered runways are treated in a similar manner as operations on a runway contaminated with standing water. The only difference is that because of different densities, a measurable depth of wet loose snow (50% the density of water) or slush (85% the density of water) must first be converted to an equivalent depth of standing water. This is accomplished by using the conversion data presented in Table 1a below. The data in this table can be interpolated for intermediate depths of contamination, e.g., 15 mm (0.6 in) of wet loose snow is equivalent to 7.5 mm (0.3 in) of standing water. Otherwise, hydroplaning speeds, tire displacement drag and spray impingement drag on runways with wet loose snow and slush are determined in a manner that is similar to a runway contaminated with standing water. This equivalent water depth is the value to be used as the Runway Surface Contamination (RSC) depth when computing takeoff performance.
• EASA has developed separate standards for classifying dry loose snow and wet loose snow. Under the new EASA contaminated runway rules for runways contaminated with dry loose snow, it is no longer necessary to account for spray impingement drag and hydroplaning speeds. Therefore, it is possible to takeoff and land in a much greater depth of dry loose snow than wet loose snow. In addition, dry loose snow is assumed to have a density that is only 20% the density of water. In consideration of these differences, Gulfstream has determined that it is conservative to divide the effective dry loose snow depth by 6 in order to establish the equivalent water depth to use when determining takeoff performance on a runway contaminated by dry loose snow. Hence, 21 mm (0.84 in.) of dry loose snow converts to 3.5 mm (0.14 in) of standing water.

Source: Gulfstream G450 Operational Information Supplement, G450-OIS-02, Section A.

• When available, ATC furnishes pilots the quality of braking action received from pilots. The quality of braking action is described by the terms “good,” “good to medium,” “medium,” “medium to poor,” “poor,” and “nil.” When pilots report the quality of braking action by using the terms noted above, they should use descriptive terms that are easily understood, such as, “braking action poor the first/last half of the runway,” together with the particular type of aircraft.
• When tower controllers receive runway braking action reports which include the terms medium, poor, or nil, or whenever weather conditions are conducive to deteriorating or rapidly changing runway braking conditions, the tower will include on the ATIS broadcast the statement, “BRAKING ACTION ADVISORIES ARE IN EFFECT.”
• During the time that braking action advisories are in effect, ATC will issue the most recent braking action report for the runway in use to each arriving and departing aircraft. Pilots should be prepared for deteriorating braking conditions and should request current runway condition information if not issued by controllers. Pilots should also be prepared to provide a descriptive runway condition report to controllers after landing.

Source: Aeronautical Information Manual §4−3−8

A Pilot Report (PIREP) reflecting the brake contribution to the airplane’s deceleration. A PIREP Braking Action Report reflects the pilots’ impression of the available wheel braking. The report may also be based on directional control feedback. The parameters are as follows;

• Good – Braking deceleration is normal for the wheel braking effort applied, and directional control is normal.
• Good to Medium – Braking deceleration OR directional control is between Good and Medium; i.e. Braking deceleration is between “normal and noticeably reduced for the wheel braking effort applied” AND “directional control is between normal and noticeably reduced”.
• Medium – Braking deceleration is noticeably reduced for the wheel braking effort applied OR directional control is noticeably reduced.
• Medium to Poor – Braking deceleration OR directional control is between Medium and Poor; i.e., Braking deceleration is between “noticeably reduced and significantly reduced for the wheel braking effort applied” AND “directional control is between noticeably reduced and significantly reduced”.
• Poor – Braking deceleration is significantly reduced for the wheel braking effort applied OR directional control is significantly reduced.
• Nil – Braking deceleration is minimal to non-existent for the wheel braking effort applied OR directional control is uncertain.

Source: SAFO 19003, Pilot Braking Action Report

Items to be considered to determine if the braking action report is reliable:

• Similar weight and class of airplane. An example would be the Boeing 737 and Airbus 320, where the weight and gear track are similar.
• Time since braking action report was given. For example, stable conditions with cold temperature and no active precipitation will likely be reliable for a longer time than reports provided during an active precipitation event with temperatures near 0-degrees Celsius.

Source: SAFO 19003, Reliable Braking Action Report

Landing overruns that occur on wet runways typically involve multiple contributing factors such as long touchdown, improper use of deceleration devices, tailwind and less available friction than expected. Several recent runway-landing incidents/accidents have raised concerns with wet runway stopping performance assumptions. Analysis of the stopping data from these incidents/accidents indicates the braking coefficient of friction in each case was significantly lower than expected for a wet runway as defined by Title 14 of the Code of Federal Regulations (14 CFR) part 25 § Section 25.109 and Advisory Circular (AC) 25-7D methods. These incidents/accidents occurred on both grooved and un-grooved runways. The data indicates that applying a 15% safety margin to wet runway time-of-arrival advisory data, as recommended by SAFO 06012 (or current guidance), may be inadequate in certain wet runway conditions. Takeoff and Landing Performance Assessment (TALPA) procedures implemented by the FAA on October 1, 2016, added new insight as to how flightcrews can evaluate runway braking performance prior to landing. TALPA defines WET as “Includes damp and 1/8-inch depth or less of water,” while CONTAMINATED is “greater than 1/8-inch of water.”

Source: SAFO 19003, Background

To comply with § 139.339, the airport operator must utilize the NOTAM system as the 5.1.3primary method for collection and dissemination of airport information to air carriers and other airport users. When disseminating airport condition information there are three methods available to airport operators. The first and preferred method is NOTAM Manager, a direct-entry system.

Source: AC 150/5200-30D, ¶5.1.3

1. Aircraft braking coefficient is dependent upon the surface friction between the tires on the aircraft wheels and the pavement surface. Less friction means less aircraft braking coefficient and less aircraft braking response.
2. Runway condition code (RwyCC) values range from 1 (poor) to 6 (dry). For frozen contaminants on runway surfaces, a runway condition code reading of 4 indicates the level when braking deceleration or directional control is between good and medium.
3. Airport management should conduct runway condition assessments on wet runways or runways covered with compacted snow and/or ice.
1. Numerical readings may be obtained by using the Runway Condition Assessment Matrix (RCAM). The RCAM provides the airport operator with data to complete the report that includes the following:
1. Runway(s) in use
2. Time of the assessment
3. Runway condition codes for each zone (touchdown, mid−point, roll−out)
4. Pilot−reported braking action report (if available)
5. The contaminant (for example, wet snow, dry snow, slush, ice, etc.)
2. Assessments for each zone (see 4−3−9c1(c)) will be issued in the direction of takeoff and landing on the runway, ranging from “1” to “6” to describe contaminated surfaces.
3. When any 1 or more runway condition codes are reported as less than 6, airport management must notify ATC for dissemination to pilots.
4. Controllers will not issue runway condition codes when all 3 segments of a runway are reporting values of 6.
4. When runway condition code reports are provided by airport management, the ATC facility providing approach control or local airport advisory must provide the report to all pilots.
5. Pilots should use runway condition code information with other knowledge including aircraft performance characteristics, type, and weight, previous experience, wind conditions, and aircraft tire type (such as bias ply vs. radial constructed) to determine runway suitability.
6. The Runway Condition Assessment Matrix identifies the descriptive terms “good,” “good to medium,” “medium,” “medium to poor,” “poor,” and “nil” used in braking action reports.

Source: Aeronautical Information Manual §4−3−9

Following the overrun accident of a Boeing-737 in December of 2005, the FAA found that the current state of the industry practices did not have adequate guidance and regulation addressing operation on non-dry, non-wet runways, i.e., contaminated runways. As such, the FAA chartered an Aviation Rulemaking Committee (ARC) to address Takeoff and Landing Performance Assessment (TALPA) requirements for the appropriate parts 23, 25, 91 subpart K, 121, 125, 135, and 139. In formulating recommendations, it became clear to the ARC that the ability to communicate actual runway conditions to the pilots in real time and in terms that directly relate to expected aircraft performance was critical to the success of the project.

Source: AC 150/5200-30D, ¶1.2.1

FAA-approved friction measuring equipment may be employed to help in determining the effects of friction-enhancing treatments, in that it can show the trend of a runway as to increasing or decreasing friction. Airport operators should not attempt to correlate friction readings (Mu numbers) to Good/Medium (previously known as Fair)/Poor or Nil runway surface conditions, as no consistent, usable correlation between Mu values and these terms has been shown to exist to the FAA’s satisfaction. It is important to note that while manufacturers of the approved friction measuring equipment may provide a table that correlates braking action to Mu values, these correlations are not acceptable to the FAA. To ensure that data collected are accurate, qualified personnel should use FAA-approved equipment and follow the manufacturer’s instructions for use. Note: It is no longer acceptable to report or disseminate friction (Mu) values to aircraft operators. This includes informal dissemination outside of the NOTAM system. In support of this change the NOTAM system will no longer allow for the reporting of this information. Airplane braking performance cannot be directly related to Friction (Mu) values. Runway Condition Codes, which will be included in the runway condition NOTAM, where applicable, are directly relevant to the determination of required landing distances.

Source: AC 150/5200-30D, ¶5.2

There are two basic types of friction measuring equipment that can be used for conducting friction surveys on runways during winter operations: Continuous Friction Measuring Equipment (CFME) and Decelerometers (DEC).

• Continuous Friction Measuring Equipment (CFME). CFME devices are recommended (over Decelerometers) for measuring friction characteristics of pavement surfaces covered with contaminants, as they provide a continuous graphic record of the pavement surface friction characteristics with friction averages for each one-third zone of the runway length.
• Decelerometers. Decelerometers are recommended (over CFMEs) for airports where the longer runway downtime required to complete a friction survey is unacceptable and for busy airports where it is difficult to gain access to the full length of a runway crossed by another runway. Decelerometers should be of the electronic type due to the advantages noted below. Mechanical decelerometers may be used, but should be reserved as a backup. Airports having only mechanical devices should plan to upgrade as soon as possible. Neither type of decelerometer will provide a continuous graphic record of friction for the pavement surface condition. They provide only a spot check of the pavement surface. On pavements with frozen contaminant coverage of less than 25 percent, decelerometers are used only on the contaminated areas. For this reason, a survey taken under such conditions will result in a conservative representation of runway braking conditions. This should be considered when using friction values as an input into decisions about runway treatments. In addition, any time a pilot may experience widely varying braking along the runway, it is essential that the percentage of contaminant coverage be noted in any report.
• Electronic decelerometers eliminate potential human error by automatically computing and recording friction averages for each one-third zone of the runway. They also provide a printed record of the friction survey data.
• Mechanical decelerometers may be used as a backup to an electronic decelerometer. The runway downtime required to complete a friction survey will be longer than with an electronic decelerometer. Mechanical decelerometers do not provide automatic friction averages or a printed copy of data.

Source: AC 150/5200-30D, ¶1.11

Lateral Location. On runways that serve primarily narrow-body airplanes, runway friction surveys should be conducted approximately 10 feet (3 m) from the runway centerline. On runways that serve primarily wide-body airplanes, runway friction surveys should be conducted approximately 20 feet (6 m) from the runway centerline. Unless surface conditions are noticeably different on the two sides of the runway centerline, only one survey is needed, and it may be conducted on either side.

Source: AC 150/5200-30D, ¶5.2.2.3.1

The RCAM is the method by which an airport operator reports a runway surface assessment when contaminants are present. Use of the RCAM is only applicable to paved runway surfaces. Once an assessment has been performed, the RCAM defines the format for which the airport operator reports and receives a runway condition “Code” via the NOTAM System. The reported information allows a pilot to interpret the runway conditions in terms that relate to airplane performance. This approach is a less subjective means of assessing runway conditions by using defined objective criteria. Aircraft manufacturers have determined that variances in contaminant type, depth, and air temperature can cause specific changes in aircraft braking performance. At the core of the RCAM is its ability to differentiate among the performance characteristics of given contaminants.

Source: AC 150/5200-30D, ¶5.3.1

Conditions Acceptable to Use Decelerometers or Continuous Friction Measuring Equipment to Conduct Runway Friction Surveys on Frozen Contaminated Surfaces.

5.1.4.1. The data obtained from such runway friction surveys are considered to be reliable only when the surface is contaminated under any of the following conditions:

1. Ice or wet ice. Ice that is melting or ice with a layer of water (any depth) on top. The liquid water film depth of .04 inches (1 mm) or less is insufficient to cause hydroplaning.
2. Compacted snow at any depth.
3. Dry snow 1 inch (25.4 mm) or less.
4. Wet snow or slush 1/8 inch (3 mm) or less.

5.1.4.2. It is not acceptable to use decelerometers or continuous friction measuring equipment to assess any contaminants outside of these parameters.

Source: AC 150/5200-30D, ¶5.1.4

The RCAM is the method by which an airport operator reports a runway surface assessment when contaminants are present. Use of the RCAM is only applicable to paved runway surfaces. Once an assessment has been performed, the RCAM defines the format for which the airport operator reports and receives a runway condition “Code” via the NOTAM System. The reported information allows a pilot to interpret the runway conditions in terms that relate to airplane performance. This approach is a less subjective means of assessing runway conditions by using defined objective criteria.

Source: AC 150/5200-30D, ¶5.3.1

Downgrade Assessment Criteria. When data from the shaded area in the RCAM (i.e., CFME/deceleration devices, pilot reports, or observations) suggest conditions are worse than indicated by the present contaminant, the airport operator should exercise good judgment and, if warranted, report lower runway condition codes than the contamination type and depth would indicate in the RCAM. While pilot reports (PIREPs) of braking action provide valuable information, these reports rarely apply to the full length of the runway as such evaluations are limited to the specific sections of the runway surface in which wheel braking was utilized. It is not appropriate to use downgrade assessment criteria to upgrade contaminant based assessments of condition codes (e.g., from 2 to 3).

Source: AC 150/5200-30D, ¶5.3.3.2.

The correlation of the Mu (μ) values with runway conditions and condition codes in the RCAM are only approximate ranges for a generic friction measuring device and are intended to be used for an upgrade or downgrade of a runway condition code. Airport operators should use their best judgment when using friction measuring devices for downgrade assessments, including their experience with the specific measuring devices used.

Source: AC 150/5200-30D, ¶5.3.3.2.1

Vehicle Deceleration or Directional Control Observation. This column is used to correlate estimated vehicle braking experienced on a given contaminant.

Source: AC 150/5200-30D, ¶5.3.3.2.2

Pilot Reported Braking Action. This is a report of braking action on the runway, by a pilot, providing other pilots with a degree/quality of expected braking. The braking action experienced is dependent on the type of aircraft, aircraft weight, touchdown point, and other factors.

1. Good: Braking deceleration is normal for the wheel braking effort applied, and directional control is normal.
2. Good-to-Medium: Braking deceleration or directional control is between good and medium braking action.
3. Medium: Braking deceleration is noticeably reduced for the wheel braking effort applied, or directional control is noticeably reduced.
4. Medium-to-Poor: Braking deceleration or directional control is between medium and poor.
5. Poor: Braking deceleration is significantly reduced for the wheel braking effort applied, or directional control is significantly reduced.
6. Nil: Braking deceleration is minimal to non-existent for the wheel braking effort applied, or directional control is uncertain.

Source: AC 150/5200-30D, ¶5.3.3.2.3

Many airports throughout Canada are equipped with mechanical and electronic decelerometers which are used to obtain an average of the runway friction measurement. The average decelerometer reading of each runway is reported as the Canadian Runway Friction Index (CRFI). Experience has shown that results obtained from the various types of decelerometers on water and slush are not accurate, and the CRFI will not be available when these conditions are present.

Source: Transport Canada Aeronautical Information Manual, ¶1.1.4

Information concerning snow, slush, ice and standing water on aerodrome/heliport pavements shall, when reported by means of a SNOWTAM, contain the information in the SNOWTAM Format in Appendix 2.

Source: ICAO Annex 15] ¶5.2.3

USAF has established RCR procedures for determining the average deceleration readings of runways under conditions of water, slush, ice, or snow. The use of RCR code is dependent upon the pilot's having a stopping capability chart specifically applicable to his/her aircraft. USAF offices furnish RCR information at airports serving USAF and ANG aircraft.

Source: U.S. FAA Order JO 7110.10W §4-4-3 ¶11

Large transport category airplanes: Turbine engine powered: Landing limitations: Destination airports.

(b) Except as provided in paragraph (c), (d), (e), or (f) of this section, no person operating a turbine engine powered large transport category airplane may take off that airplane unless its weight on arrival, allowing for normal consumption of fuel and oil in flight (in accordance with the landing distance in the Airplane Flight Manual for the elevation of the destination airport and the wind conditions expected there at the time of landing), would allow a full stop landing at the intended destination airport within 60 percent of the effective length of each runway described below from a point 50 feet above the intersection of the obstruction clearance plane and the runway. For the purpose of determining the allowable landing weight at the destination airport the following is assumed:

(1) The airplane is landed on the most favorable runway and in the most favorable direction, in still air.

(2) The airplane is landed on the most suitable runway considering the probable wind velocity and direction and the ground handling characteristics of the airplane, and considering other conditions such as landing aids and terrain.

(c) A turbopropeller powered airplane that would be prohibited from being taken off because it could not meet paragraph (b)(2) of this section, may be taken off if an alternate airport is selected that meets all of this section except that the airplane can accomplish a full stop landing within 70 percent of the effective length of the runway.

(d) Unless, based on a showing of actual operating landing techniques on wet runways, a shorter landing distance (but never less than that required by paragraph (b) of this section) has been approved for a specific type and model airplane and included in the Airplane Flight Manual, no person may take off a turbojet airplane when the appropriate weather reports or forecasts, or any combination of them, indicate that the runways at the destination airport may be wet or slippery at the estimated time of arrival unless the effective runway length at the destination airport is at least 115 percent of the runway length required under paragraph (b) of this section.

(e) A turbojet airplane that would be prohibited from being taken off because it could not meet paragraph (b)(2) of this section may be taken off if an alternate airport is selected that meets all of paragraph (b) of this section.

(f) An eligible on-demand operator may take off a turbine engine powered large transport category airplane on an on-demand flight if all of the following conditions exist:

(1) The operation is permitted by an approved Destination Airport Analysis in that person's operations manual.

(2) The airplane's weight on arrival, allowing for normal consumption of fuel and oil in flight (in accordance with the landing distance in the Airplane Flight Manual for the elevation of the destination airport and the wind conditions expected there at the time of landing), would allow a full stop landing at the intended destination airport within 80 percent of the effective length of each runway described below from a point 50 feet above the intersection of the obstruction clearance plane and the runway. For the purpose of determining the allowable landing weight at the destination airport, the following is assumed:

(i) The airplane is landed on the most favorable runway and in the most favorable direction, in still air.

(ii) The airplane is landed on the most suitable runway considering the probable wind velocity and direction and the ground handling characteristics of the airplane, and considering other conditions such as landing aids and terrain.

(3) The operation is authorized by operations specifications.

Source: 14 CFR 135, ¶135.385

The mass of the aeroplane:

1. at the start of the take-off; or
2. in the event of in-flight replanning, at the point from which the revised operational flight plan applies,

shall not be greater than the mass at which the requirements of the appropriate chapter can be complied with for the flight to be undertaken. Allowance may be made for expected reductions in mass as the flight proceeds and for fuel jettisoning.

Source: EASA Air Ops Annex 1 to VIII, §ANNEX IV, ¶CAT.POL.A.105 (a)

The landing mass of the aeroplane determined in accordance with CAT.POL.A.105(a) for the estimated time of landing at the destination aerodrome and at any alternate aerodrome shall allow a full stop landing from 50 ft above the threshold:

1. for turbo-jet powered aeroplanes, within 60 % of the landing distance available (LDA); and
2. for turbo-propeller powered aeroplanes, within 70 % of the LDA.

Source: EASA Air Ops Annex 1 to VIII, §ANNEX IV, ¶CAT.POL.A.230 (a)

For dispatching the aeroplane it shall be assumed that:

1. the aeroplane will land on the most favourable runway, in still air; and
2. the aeroplane will land on the runway most likely to be assigned, considering the probable wind speed and direction, the ground handling characteristics of the aeroplane and other conditions such as landing aids and terrain.

Source: EASA Air Ops Annex 1 to VIII, §ANNEX IV, ¶CAT.POL.A.230 (e)

These distances are advisory performance data (i.e., not required by regulation) intended to provide a more accurate assessment of actual landing distance at time of arrival, considering factors that cannot be accurately predicted at time of preflight, such as runway contaminants, winds, speed additives, and touchdown points. These distances may be based upon the use of reverse thrust, ground spoilers, autobrakes, etc.

Source: SAFO 19003, Landing Distance at Time of Arrival

For the purpose of this guidance, Time of Arrival is a point in time close enough to the airport to allow the crew to obtain the most current meteorological and runway surface conditions considering pilot workload and traffic surveillance, but no later than the commencement of the approach procedures or visual approach pattern.

Source: SAFO 19003, At Time of Arrival

An assessment is initially performed when landing weather and field conditions are obtained, usually around Top of Descent (TOD). It is important to note the time of the latest Field Condition report and any associated reliable braking action reports. A number of overruns have occurred when pilots were provided with a runway condition that was no longer reliable given changes in meteorological conditions. Pilots are strongly advised to review the weather conditions and compare that to the time of the latest braking action report. The assessment should include consideration of how much deterioration in field conditions can be tolerated, the minimum RwyCC(s), and Field Condition (FICON) or Braking Action Reports needed to safely land, should those factors deteriorate from the ones used in the TOD landing distance.

Source: SAFO 19003, Timeliness

IN-FLIGHT DETERMINATION OF THE LANDING DISTANCE. The in-flight determination of the landing distance should be based on the latest available meteorological or runway state report, preferably not more than 30 minutes before the expected landing time.

Source: EASA Air Ops Annex 1 to VIII, §ANNEX IV, ¶CAT.OP.MPA.300

Unless, based on a showing of actual operating landing techniques on wet runways, a shorter landing distance (but never less than that required by [the dry runway rules] of this section) has been approved for a specific type and model airplane and included in the Airplane Flight Manual, no person may take off a turbojet airplane when the appropriate weather reports or forecasts, or any combination of them, indicate that the runways at the destination airport may be wet or slippery at the estimated time of arrival unless the effective runway length at the destination airport is at least 115 percent of the runway length required under [the dry runway rules] of this section.

Source: 14 CFR 121, §121.195(d)] and [14 CFR 135, §135.385(d)

• 7.2.1. When the appropriate weather reports or forecasts or a combination thereof indicate that the runway at the estimated time of arrival may be wet, the landing distance available should be at least 115 per cent of the required landing distance determined in accordance with [dry runway conditions].
• A landing distance on a wet runway shorter than that required by 7.2.1 but not less than that required by [dry runway conditions] may be used if the flight manual includes specific additional information about landing distance on wet runways.

Source: ICAO Annex 6, Part 1, Att C, Page C-7

Landing — wet and contaminated runways.

1. When the appropriate weather reports and/or forecasts indicate that the runway at the estimated time of arrival may be wet, the LDA shall be at least 115 % of the required landing distance, determined in accordance with CAT.POL.A.230.
2. When the appropriate weather reports and/or forecasts indicate that the runway at the estimated time of arrival may be contaminated, the LDA shall be at least the landing distance determined in accordance with (a), or at least 115 % of the landing distance determined in accordance with approved contaminated landing distance data or equivalent, whichever is greater. The operator shall specify in the operations manual if equivalent landing distance data are to be applied.
3. A landing distance on a wet runway shorter than that required by (a), but not less than that required by CAT.POL.A.230(a), may be used if the AFM includes specific additional information about landing distances on wet runways.
4. A landing distance on a specially prepared contaminated runway shorter than that required by (b), but not less than that required by CAT.POL.A.230(a), may be used if the AFM includes specific additional information about landing distances on contaminated runways.
5. For (b), (c) and (d), the criteria of CAT.POL.A.230 shall be applied accordingly, except that CAT.POL.A.230(a) shall not be applied to (b) above.

Source: EASA Air Ops Annex 1 to VIII, §ANNEX IV, ¶CAT.POL.A.235

Unless, based on a showing of actual operating landing techniques on wet runways, a shorter landing distance (but never less than that required by [dry runway rules] of this section) has been approved for a specific type and model airplane and included in the Airplane Flight Manual, no person may take off a turbojet airplane when the appropriate weather reports or forecasts, or any combination of them, indicate that the runways at the destination or alternate airport may be wet or slippery at the estimated time of arrival unless the effective runway length at the destination airport is at least 115 percent of the runway length required under [dry runway rules] of this section.

Source: 14 CFR 91, §91.1037(e)

Preflight planning requirements for part 91 operators are governed by §§ 91.103 and 91.605. It is highly recommended that part 91 operators and pilots calculate predeparture landing distance performance requirements based on the guidance contained in their AFM, and employ the landing assessment process before initiating the approach landing phase of the flight, and consider the factors presented in this AC to avoid a runway overrun.

Source: AC 91-79A, appendix 2, ¶2.a.] Part 91 Operational Recommendations.

If advisory data for a landing distance assessment at time-of-arrival is not available from the manufacturer, performance provider data may be used. If performance-provider data is not available, the landing distance factors (LDF) from Table 1, Landing Distance Factors, may be used. To find the Landing Distance Required (LDR), multiply the certificated (i.e., AFM dry, unfactored) Landing Distance by the applicable LDF in Table 1 for the runway conditions existing at the time of arrival. If the AFM landing distances are presented as factored landing distances, then those data must be adjusted to remove the applicable preflight factors applied to that data. The LDFs given in Table 1 include a 15 percent safety margin, an air distance representative of normal operational practices, a reasonable accounting for temperature, the effect of increased approach speed, reduced wheel braking, reverse thrust usage (or not), the additional effect of reduced wheel braking capability on altitude and wind distance adjustment.

Source: SAFO 19001

The touchdown point used in the performance data assessment reflects the assumed air distance. Operational landing data usually includes an allowance for 1,500 feet or 7 seconds of air distance from the threshold to touchdown. An air distance as short as 1,000 feet may be used IF an operator’s landing assessment procedures include enhancements to minimize the risk of overruns or undershoots, including:

1. Training in touchdown control and short field landing techniques.
2. Identification of required touchdown point and training to assure go-around procedures are initiated if unable to achieve a suitable touchdown point.
3. Approach guidance and runway markings on the specific runway are consistent with a shorter air distance.
4. Operational data (without the need for interpolation) are provided to the crew for the specific runway, conditions, and aircraft landing configuration.
5. The flight techniques assumed in the creation of the performance data used for a shorter air distances are based on flight techniques to be used in the shorter air distance operation.

Source: SAFO 19001, Touchdown Point

Landing distances based on 3.5° glide path at 50 feet and 8 FPS sink rate at touchdown.

Source: Gulfstream G550 Aircraft Operating Manual, §13-03-20, ¶1.A.(3)

A proper flare reduces the aircraft’s rate of descent to achieve the desired firm landing. If the flare is extended while additional speed is bled off, additional runway will be used. An extended flare may also result in an increase in pitch attitude, which may lead to a tail strike. A firm landing does not mean a hard landing, but rather a deliberate or positive touchdown at the desired touchdown point. A landing executed solely for passenger comfort considerations, which extends the touchdown point beyond the touchdown zone (TDZ), is not impressive, desirable, or consistent with safety or regulations. It is essential to fly the airplane onto the runway at the target touchdown point.

Not everyone publishes landing touchdown rates. Some give flare times, make general statements, or don't say anything at all. Here are some examples that do and do not:

Source: AC 91-79A, appendix 1, ¶6.

The reference landing distance is the distance from threshold to complete stop. It includes an air distance allowance from threshold to touchdown associated with a flare time of 7 seconds.

Source: Boeing 787-BBJ Flight Crew Operations Manual, §PI.17.7

FULL STOP LANDING — Perform partial flare, and touchdown without holding off.

Source: Bombardier BD-700 Airplane Flight Manual, §04-08-16, ¶12

Load Factors / Landing . . . +3.5G / This acceleration represents landing at a sink rate, at touchdown, of 600 feet per minute.

Source: Cessna Citation X Model 750 Airplane Flight Manual, p.2-310-5

Landing distances based on 3.5° glide path at 50 feet and 8 FPS sink rate at touchdown.

Source: Gulfstream G550 Aircraft Operating Manual, §13-03-20, ¶1.A.(3)

Thrust Reversers. In the event of an asymmetric deployment, the nosewheel on the ground will aid in directional control. If the thrust reversers deploy asymmetrically, or if the airplane begins to drift due to a crosswind, close the thrust reversers and reestablish directional control. Once the airplane’s track down the runway is reestablished, redeploy the thrust reversers. Use airplane steering in accordance with the AFM procedures.

Source: AC 91-79A, appendix 1, ¶5.j.

The take-off field length data on wet runways are based on both thrust reversers operable and assumes that maximum available reverse thrust is used down to a complete stop.

Source: Bombardier BD-700 Airplane Flight Manual, §06-01-1, ¶1.A.(7)

ACTUAL LANDING DISTANCE ON CONTAMINATED RUNWAYS — The following charts are used to obtain the actual landing distance on contaminated runways, for a slat OUT / flap 30° landing, for a given value of airplane weight, airport pressure altitude, reported wind, landing approach speed (VREF) increment and number of operable thrust reversers.

Source: Bombardier BD-700 Airplane Flight Manual, §06-01-1, ¶1.A.(7)

No operation should be predicated on the use of thrust reversers.

Source: CL605 AFM, §03-01-1, ¶2.

Field Length Limited Performance. No reverse thrust credit was taken for accelerate-stop distances computed for dry runways; however, the use of reverse thrust is recommended to reduce the braking distance and the kinetic energy absorbed by the brakes. Wet runway accelerate-stop distances are calculated assuming the deployment of one or both thrust reversers.

Source: Gulfstream G450 Airplane Flight Manual, §05-02-10, ¶1

Deploy thrust reversers as required. Note that reverse thrust credit is not shown in the landing distance charts, but the use of reverse thrust will result in distances less than those computed and significantly improve brake wear characteristics.

Source: Gulfstream G450 Airplane Flight Manual, §05-11-20, ¶3.B.(3)

Hydroplaning Causal Factors. Hydroplaning is a condition that can exist when an airplane has landed on a runway surface contaminated with standing water, slush, and/or wet snow. Hydroplaning can have serious adverse effects on ground controllability and braking efficiency. The three basic types of hydroplaning are dynamic, reverted rubber, and viscous. Any one of the three can render an airplane partially or totally uncontrollable anytime during the landing roll. Hydroplaning is a significant factor that should be considered in determining stopping or steering capability on a contaminated or otherwise flooded runway. Hydroplaning depends on wheel speed and tire pressure. The key item to remember when the airplane is hydroplaning is that the tires are no longer in contact with the runway, although the airplane is not airborne. Though at high speeds, aerodynamic drag can provide a significant decelerating force. Reverse thrust/propeller reversing, if installed, provides nearly all the decelerating force when hydroplaning since the brakes are essentially ineffective. These characteristics are included in the distances presented in the contaminated runway supplemental data when provided by the airplane manufacturer.

Source: AC 91-79A, appendix 3, ¶11.a.

Dynamic hydroplaning is related to tire inflation pressure. Data obtained during hydroplaning tests have shown the minimum dynamic hydroplaning speed (VP) of a tire to be 8.6 times the square root of the tire pressure in pounds per square inch (psi). For an airplane with a main tire pressure of 24 pounds, the calculated hydroplaning speed would be approximately 42 knots (kts). It is important to note that the calculated speed referred to above is for the start of dynamic hydroplaning. Once hydroplaning has started, it may persist to a significantly slower speed depending on the type being experienced.

Source: AC 91-79A, appendix 3, ¶11.a.(1)

• Hydroplaning is a function of the water depth, tire pressure and speed. Moreover, the minimum speed at which a non-rotating tire will begin to hydroplane is lower than the speed at which a rotating tire will begin to hydroplane because a build up of water under the non-rotating tire increases the hydroplaning effect. Pilots should therefore be aware of this since it will result in a substantial difference between the take-off and landing roll aircraft performance under the same runway conditions. The minimum speed, in knots, at which hydroplaning will commence can be calculated by multiplying the square root of the tire pressure (PSI) by 7.7 for a non-rotating tire, or by 9 for a rotating tire.

Source: Transport Canada Aeronautical Information Manual, ¶1.6.5

• This equation gives an approximation of the minimum speed necessary to hydroplane on a smooth, wet surface with tires that are bald or have no tread. For example, the minimum hydroplaning speeds for an aircraft with tires inflated to 49 PSI are calculated as:

Non-rotating tire:7.7 X √49 = 54 kt; or Rotating tire: 9 X √49 = 63 kt

Source: Transport Canada Aeronautical Information Manual, ¶1.6.5

• When hydroplaning occurs, the aircraft's tires are completely separated from the actual runway surface by a thin water film and they will continue to hydroplane until a reduction in speed permits the tires to regain contact with the runway. This speed will be considerably lower than the speed at which hydroplaning commences. Under these conditions, the tire traction drops to almost negligible values, and in some cases, the wheel will stop rotating entirely. The tires will provide no braking capability and will not contribute to the directional control of the aircraft. The resultant increase in stopping distance is impossible to predict accurately, but it has been estimated to increase as much as 700 percent. Further, it is known that a 10-kt crosswind will drift an aircraft off the side of a 200-ft wide runway in approximately 7 sec under hydroplaning conditions.

Source: Transport Canada Aeronautical Information Manual, ¶1.6.5

Non-Turbojet Airplanes Braking After Touchdown. Putting maximum weight on the wheels after touchdown is an important factor in obtaining optimum braking performance. During the early part of rollout, some lift continues to be generated by the wing. After touchdown, the nosewheel is lowered to the runway to maintain directional control. During deceleration, the nose may pitch down due to braking, transferring the weight from the main wheels to the nosewheel. This does not aid in braking action, so back pressure is applied to the controls without lifting the nosewheel off the runway. This enables directional control while keeping weight on the main wheels. Careful application of the brakes is initiated after the nosewheel is on the ground and directional control is established. Maximum brake effectiveness is just short of the point where skidding occurs. If the brakes are applied so hard that skidding takes place, braking becomes ineffective.

Source: AC 91-79A, appendix 1, ¶5.c.

Braking. A distinction should be made between the procedures for minimum landing distance and an ordinary landing roll with considerable excess runway available. Minimum landing distance will be obtained by creating a continuous peak deceleration of the airplane; that is, extensive use of the brakes for maximum deceleration. On the other hand, an ordinary landing roll with considerable excess runway may allow extensive use of aerodynamic drag to minimize wear and tear on the tires and brakes. If aerodynamic drag is sufficient to cause deceleration, it can be used in deference to the brakes in the early stages of the landing roll. For instance, the use of aerodynamic drag is applicable only for deceleration to 60 to 70 percent of the touchdown speed. At speeds less than 60 to 70 percent of the touchdown speed, aerodynamic drag is so slight as to be of little use, and braking must be utilized to produce continued deceleration. Since the objective during the landing roll is to decelerate, the powerplant thrust should be the smallest possible positive value (or largest possible negative value in the case of thrust reversers).

(1) There are three primary forces available for deceleration during the rollout process: wheel braking, aerodynamic drag, and reverse thrust/propeller reversing, if available. Spoilers are designed to reduce lift and transfer aircraft weight to the landing gear. Deployment of drag devices is most effective at higher speeds and is not affected by runway surface conditions. In all cases, the pilot must ensure the automatic deployment of the deceleration devices occurs. If not, the pilot must immediately manually deploy the devices to minimize the time lost to achieve as close as possible the assessed landing distance.

(2) Timely deployment of spoilers will increase drag by 50 to 60 percent, but more importantly, deployment of the spoilers increases wheel loading by as much as 200 percent in the landing flap configuration. This increases the tire-to-ground friction force, making the maximum tire braking forces available. Many airplanes with autospoilers installed require weight on wheels to deploy the spoilers, which reinforces the requirement for a positive touchdown, as a soft touchdown can delay the automatic deployment. Spoiler deployment immediately after touchdown provides the greatest benefit.

(3) When minimum landing distances are considered, braking friction forces predominate during the landing roll and, for the majority of airplane configurations, braking friction is the main source of deceleration when the runway is dry.

Source: AC 91-79A, appendix 1, ¶5.d.

Wet and Contaminated Runway Surface. When the runway is wet or slippery, reverse thrust (if the airplane is equipped) may be the dominant deceleration force just after touchdown, and throughout the deceleration if the runway has poor or worse braking conditions. As the airplane slows down, the wheel brakes become the dominant deceleration force. When the runway length is limited, for airplanes equipped with an antiskid system, maximum wheel braking should be applied immediately after touchdown. For airplanes without an antiskid system, slow back pressure should be applied to the yoke such that it will not raise the nose of a nose gear airplane for aerodynamic braking while maximum braking that will not cause skidding is applied. In all situations, braking should be maintained until the airplane slows to a safe taxi speed for the conditions.

Source: AC 91-79A, appendix 1, ¶5.e.

Autobrakes. If the airplane is equipped with autobrakes, manufacturers recommend the use of the autobrakes for all landings on contaminated runways. Autobrakes are applied earlier in the landing roll, and to the level selected by the pilot(s) or flightcrew for the anticipated landing condition, and runway available, and provide the most efficient and timely use of braking action. However, the pilot must ensure that if the autobrakes do not engage upon touchdown, then manual braking must be applied.

Source: AC 91-79A, appendix 1, ¶5.f.

Antiskid. Application of brakes is different for airplanes equipped with a functioning antiskid braking system than for airplanes without such a system.

(1) For airplanes without an antiskid system, brakes should be applied progressively throughout the deceleration process, and the pilot must recognize the point that wheel skid occurs. Maximum braking effectiveness occurs just prior to the point where wheel skidding occurs. However, should a skid occur, releasing brake pressure can stop skidding and then maximum braking can be reestablished until the deceleration process is completed. Pilots should be aware that a skid is most likely at higher speeds and at that point may not be perceptible.

(2) For airplanes with an antiskid system, to achieve the benefits of antiskid, the brakes must be applied firmly throughout the deceleration process. When maximum braking is required, it is accomplished by holding maximum brake application pressure and allowing the antiskid system to operate. Letting up on the brakes (unless required to regain directional control) defeats the purpose of the antiskid system. The pulsation caused by the modulation of the brake pressure by the antiskid system indicates that the antiskid system is operating normally, although the pulsation may be disconcerting to the pilot.

Source: AC 91-79A, appendix 1, ¶5.g.

After touchdown, continue to increase back pressure on the stick to obtain the highest possible nose-high attitude without flying the aircraft off the runway. Just prior to loss o elevator authority, lower the nosewheel to the runway. After the nosewheel is lowered to the runway, a single, smooth brake application should be used to stop. This technique could increase landing distance as much as 50 percent from that computed from the landing distance chart in Part 7 of Appendix.

Source: 1-TO-T-38A-1, p. 2-12

V_MCL is the minimum control speed during approach and landing with all engines operating, is the calibrated airspeed at which, when the critical engine is suddenly made inoperative, it is possible to maintain control of the airplane with that engine still inoperative, and maintain straight flight with an angle of bank of not more than 5 degrees. VMCL must be established with—
(1) The airplane in the most critical configuration (or, at the option of the applicant, each configuration) for approach and landing with all engines operating;
(2) The most unfavorable center of gravity;
(3) The airplane trimmed for approach with all engines operating;
(4) The most favorable weight, or, at the option of the applicant, as a function of weight;
(5) For propeller airplanes, the propeller of the inoperative engine in the position it achieves without pilot action, assuming the engine fails while at the power or thrust necessary to maintain a three degree approach path angle; and
(6) Go-around power or thrust setting on the operating engine(s).

Source: 14 CFR 25.149 (f)

The landing distance required by § 25.125 without any factors applied. This landing distance is based on dry runway wheel braking and does not need to include runway slope or air temperature accountability, or approach speed additives. It may be based on aggressive flight test techniques when determining the air distance, and does not take credit for reverse thrust or account for the effect of autobrakes. The Unfactored Certified AFM Landing Distance may be used with the factors from Table 1 below to determine a factored time of arrival landing distance.

Source: SAFO 19001, Unfactored Certificated Airplane Flight Manual (AFM) Landing Distance.

All takeoff and landing performance is based on a paved, dry runway.

Source: Cessna Citation CJ2+ AFM, p. 4-5

Takeoff Field Length (Wet) The takeoff field length given for each combination of gross weight, ambient temperature, altitude, wind, and runway gradients is the greatest of the following:

1. 115 percent of the two-engine horizontal takeoff distance from start to a height of 35 feet above runway surface.
2. Accelerate-stop distance.
3. The engine-out accelerate-go distance to 15 feet.
4. The Dry Takeoff Field Length.

Source: Cessna Citation CJ2+ AFM, p. S24-13

Both dry and wet runway performance is included.

Source: Gulfstream G550 AFM, §5.1, p. 5.1-1

The pilots touched down at an excessive airspeed (23 knots above Vref), more than 1,200 feet down a wet 4,305-foot-long runway, leaving about 3,100 feet for the airplane to stop. According to manufacturer calculations, about 2,710 feet of ground roll would be required after the airplane touched down, assuming a touchdown speed at Vref; a longer ground roll would be required at higher touchdown speeds. Although a 2 knot crosswind component existed at the time of the accident, the airplane's excessive airspeed at touchdown (23 knots above Vref) had a much larger effect on the outcome of the landing.

Source: NTSB ERA11FA001