Allegheny Airlines 453
Accident Case Study
Figure: Allegheny Airlines 453, N1550, from the Werner Fischdick Collection
- Date: 9 July 1978
- Time: 17:30
- Type: BAC One-Eleven 203AE
- Operator: Allegheny Airlines
- Registration: N1550
- Fatalities: 0 of 4 crew, 0 of 73 passengers
- Aircraft Fate: Damaged beyond repair
- Phase: Landing
- Airports: (Departure) Boston-Logan International Airport, MA (BOS/KBOS), United States of America; (Destination) Rochester-Monroe County Airport, NY, (ROC/KROC), United States of America
[NTSB AAR-79-2, ¶1.1.]
- At 1742:32, the flight was cleared to descend to 3,000 ft and was given a heading to intercept the localizer inbound. At 1744:26, the controller told the flight "one six miles from Breit, 21 cleared ILS runway 28 approach, maintain two thousand one hundred and report established on the localizer." The flight acknowledged the clearance.
- According to the cockpit voice recorder (CVR) tape, at 1747:12, the captain stated "this will be a two engine ILS."
- At 1748:16, the flight reported their position to the tower as being "a couple outside Breit." The tower controller cleared the flight to land. During the clearance, the surface winds were reported to be from 260° at 6 kns.
- At 1749:06, the captain called for the landing gear to be lowered. This call was followed by a configuration warning horn which sounds when the flaps are extended while the spoilers are deployed.
- At 1749:23 the first officer stated, "yeah, it looks like you got a tailwind here." The captain agreed with the comment. This conversation was followed at 1749:28 by a ground proximity warning system (GPWS) alert after which the first officer replied, "yeah, flaps are slower than....." At 1749:44, the GPWS again sounded. This alert was followed by a reply from the first officer, "yeah, twenty-six, there you got it." This was followed by a third GPWS alert at 1749:51.
- During an initial interview on July 11, 1978, the captain stated that during the approach he stayed within the speed parameters of the flaps and stayed on the glidepath. However, he stated, "We just never could dissipate all the speed that we picked up." He indicated that the 45' flap position was selected at 800 to 850 ft. The first officer's recollection was that the 45" flap position was selected about 1,000 ft. The captain could not recall receiving any altitude, airspeed, or sink-rate calls from the first officer during the approach. Although the first officer recalled making at least the 1,000-ft call, none was recorded on the CVR. During the final portion of the approach and landing, neither of the crewmembers could recall any specific airspeed or sink rates other than that the airspeed was a little fast; they did recall that Vref was 123 kns. Both crewmembers recalled that, during flap extension, it took the flaps a longer-than-normal amount of time to come down. Both crewmembers indicated that other than the slightly high airspeed there was no concern that the approach was unsafe. The captain further stated that at no time during the approach or landing did be consider a missed approach or rejected landing. Both crewmembers estimated that the aircraft touched down about 1/3 of the way down the runway. The captain stated that he flew the aircraft onto the runway "three point", and made a normal attempt to stop. He said that at touchdown the spoilers were deployed and reverse thrust was selected. He further stated that, "I didn't feel that we really got a good reverse response from the engines, although we did get cockpit indications that the clam shells opened."
- On December 8, 1978, the cockpit crew was interviewed again to resolve some unanswered questions generated by the review of findings from the recorders, a performance study, and a medical examination of the captain. During his interview, the first officer stated that (1) the aircraft was within the prescribed speeds for the extension of the landing gear and the flaps; (2) he did not agree with the speeds reflected by the flight data recorder, but the speeds he could recall were "relatively high"; (3) he believed that the approach should not have continued past the outer marker because the speeds were too high; (4) he normally makes the required callouts and could not explain their absence in this case; (5) the captain made all flap selections during the approach; (6) the captain selected reverse thrust before speed brakes; (7) he considered going around many times and tried to warn the captain in subtle ways like mentioning the possibility of a tailwind and the slowness of flap extension; (8) he thought the captain understood the meaning of these remarks and would take the appropriate action; (9) he tried to take control after touchdown but the captain had both hands on the controls; and (10) after touchdown he believes he said "go Jack" to indicate the need for a go-around instead of "oh Jack", as transcribed from the CVR.
- The captain's testimony was essentially the same as given during the previous interview, except that (1) he didn't interpret the tailwind remarks made by the first officer to mean that they were too fast; (2) he confirmed his reported medical history; and (3) there were no problems which prevented the approach and landing from being foremost in his mind.
- According to flight data recorder (FDR) information, the aircraft crossed the runway threshold at a speed of about 184 kns indicated airspeed (KIAS)--61 kns above Vref. About 1750:08, the aircraft's nose wheel touched down on the runway about 2,540 f t down the runway at 163 kns. This was followed by the touchdown and subsequent failure of the right main landing gear tires at a point about 3,000 ft down the runway at a speed of about 159 kns. This was followed by the touchdown and subsequent failure of the left main landing gear inboard tire about 3,960 ft down the runway at 143 KIAS.
- About 7 sec after the inboard tire of the left main landing gear failed, the aircraft departed the end of the runway at a speed of about 102 kns. Following its departure from the end of the runway, the aircraft traveled about 425 ft down a gradual slope and then traversed a 35-ft-wide, 10-ft-deep drainage ditch. Impact with the drainage ditch caused the nose landing gear to collapse rearward and both main landing gear to separate from the aircraft. The aircraft continued on and came to a rest about 728 ft past the departure end of the runway, 143 ft to the left of the extended runway centerline, on a heading of 334' magnetic.
- The Rochester tower ground controller stated that the ARTS III radar display showed a 190-kn groundspeed when the aircraft was 1/2 mile from the runway. Several ground witnesses, who were also pilots, saw the aircraft from the time that it crossed the runway threshold until it left the runway. These witnesses were located on a road adjacent to the airport. They stated that the approach seemed fast and the nose was low.
- Another tower controller said that the aircraft touched down nose gear first at a point near taxiway "Bravo", which crosses runway 28 about 2,500 ft from the runway threshold. None of the ground witnesses saw or heard any reverse thrust application.
- Passengers on board the aircraft stated that the aircraft seemed to be going very fast just before touchdown and that the aircraft's descent profile was steeper than normal. They further stated that about 3 to 4 min before landing, the spoilers were up for about 1 min. One passenger recalled hearing the noise associated with reverse thrust for about 5 sec.
[NTSB AAR-79-2, ¶2]
- The Nos. 2, 3, and 4 tires had been milled away in one spot, and the No. 1 tire had not. Therefore, either the Nos. 2, 3, and 4 antiskid units were inoperative, or the brakes were applied before the main landing gear touched down. Based on witness observations, crew testimony, runway marks, and wreckage examination, the Safety Board concludes that the nose gear touched down before the main landing gear and that the brakes were applied before the main landing gear touched down. Therefore, since the antiskid system did not have the required tire spin up before the main gear touched down with locked brakes, the tires blew.
- The entire reverser systems of both engines were functionally tested and both reversers and associated engine fuel scheduling operated satisfactorily. Although the spoiler system could not be functionally checked because of impact damage, witness observations of speed brake activation and crew statements that speed brakes were used during the descent, support a conclusion that the spoilers were operational before impact. Additionally, a review of aircraft records disclosed no recent malfunctions or abnormalities that might have lead to a malfunction of either of these systems. Although the captain stated that he deployed the spoilers and selected reverse thrust after touchdown, the extent of use of either of these systems could not be determined.
- In view of the foregoing, the Safety Board concludes that the the aircraft's airframe, systems, powerplants, and components were not factors in this accident.
- The captain allowed the aircraft to exceed the maximum airspeed limitations for operations in the National Airspace System. Federal Regulation 14 CFR 91.70 requires that aircraft be operated at indicated airspeeds of 250 kns or below at altitudes below 10,000 ft. The regulation further specifies that the maximum indicated airspeed is 200 kns for turbine-powered aircraft within a 5 statute-mile radius of the center of the airport and up to, but not including, 3,000 ft above the airport. PDR data reveal that during the descent the aircraft exceeded 250 KIAS until it reached an altitude of 6,200 ft. and that the indicated airspeed on the final approach was above 200 kns until the aircraft was within 2 statute miles of the center of the airport.
- Except for altitude control, the entire approach was unstabilized and exceeded by a significant margin both the airspeed and rate of descent limitations prescribed by Allegheny Airlines. Additionally, the gear and flaps were extended at speeds above those authorized by the company.
- Allegheny flight manual procedures for airspeed management for an ILS approach specify at least seven locations along the 7-mile final approach and landing path at which specified maximum airspeeds should not be exceeded. The procedures specified that a stabilized airspeed of 138 kn (Vref + 15) be achieved between 800 ft and 500 ft above the ground. For this speed, the rate of descent would have been 730 ft per minute at the point where the first officer (pilot not flying) was required to call out deviations from target descent rates and bug speed (Vref+additives). However, the first officer did not make any altitude calls, descent rate deviation calls, or airspeed deviation calls even though the actual rates of descent did not stabilize and exceeded the maximum descent rate of 1,000 fpm, which required a go-around.
- The dangerously high rates of descent of over 2,000 fpm within 2 miles of the threshold and the first GPWS alert should have indicated to the crew that the approach was improper and that a missed approach was necessary. None of the three GPWS alerts caused the crew to take the necessary corrective action even though company procedures dictated otherwise.
- There were no flap callouts recorded on the CVR. The captain stated that, when the configuration warning sounded, the flaps were at 18°. The CVR recorded this warning when the aircraft's airspeed was 222 kns, its altitude was 1,100 ft, and it was 3.0 mi from the threshold. At this point, flaps should have been 45' and speed should have been below 160 kns and decreasing during the next 1.4 nms to no more than the maximum stabilized airspeed of 138 kns (Vref + 15).
- The only evidence to indicate where the 45° landing flaps were selected is the captain's statement that they were set at 850 ft (290 ft a.g.1.) and the first officer's statement that they were selected at 300 ft. At these altitudes the aircraft would, have been 0.8 nms from the runway threshold and at an airspeed of 188 kns. This speed exceeds Allegheny's airspeed limit for 45° flaps by 28 kns. Moreover, the selection altitude was below the 1,000-ft limit established by Allegheny. The captain stated that he did not look at his airspeed over the threshold, but estimated it to be a little fast by a "seat of the pants" feeling. When the aircraft crossed the landing threshold at 184 kns (Vref + 61 kns), the captain's decision to continue to a landing must be considered highly unusual.
- The captain was obviously not fully cognizant of the excessive deviations from stabilized parameters because of a breakdown in crew coordination and inadequate monitoring of cockpit instruments by both he and his first officer. Such excessive deviations from a normal approach would have caused an alert and prudent captain to execute a missed approach. Yet, when questioned, the captain stated that he never considered such an action.
- While the ultimate responsibility for decisions affecting the safety of the passengers, the crew, the cargo, and the aircraft rests with the pilot-in-command, the crew concept dictates that the pilot not flying assist the flying pilot in the performance of the latter's duties to insure that the cockpit workload remains at an acceptable level throughout an approach and landing.
- The Board believes that the captain may have controlled his approach more successfully had the first officer performed the duties required by the company for the pilot not flying. Specifically, the CVR disclosed that the first officer did not make any of the required altitude, descent rate, or airspeed callouts during the approach. His failure placed added workload on the captain during the most critical period of the flight -- the approach and landing. This accident again illustrates the importance of disciplined crew coordination and emphasizes the need for flightcrew members to continue to make required, as well as meaningful, callouts, including excessive descent rates and airspeeds.
[NTSB AAR-79-2, ¶3.1]
- There is no evidence that the aircraft structure, systems, flight controls, or powerplants were involved in the causal area of this accident.
- Visual meteorological conditions existed at the time of the accident. Although there was a light wind shear, it was not significant and had no influence on the approach and landing.
- The flight data recorder functioned normally during the flight.
- During the descent for the approach to Rochester, the flight's airspeed exceeded 250 kns below 10,000 ft.
- The crew did not comply with checklist procedures during the approach and landing in that no callouts were made and cockpit instruments were not monitored.
- The crew failed to comply with recommended approach and landing airspeeds.
- The approach was not made according to prescribed procedures and was not stabilized.
- The captain applied brakes before the main landing gear was on the runway.
- The captain's decision to land was improper and causal.
- The right main landing gear contacted the runway 3,010 ft from the landing threshold at 159 kn and the left main landing gear initially contacted the runway about 3,800 ft from the threshold at 140 kn.
- The aircraft left the runway at 102 KIAS.
- A successful go-around could have been accomplished as late as 4,200 ft down the runway.
- The aircraft could not have been stopped on the runway at the speed and distance past the threshold that it landed.
[NTSB AAR-79-2, ¶3.2] The National Transportation Safety Board determines that the probable cause of the accident was the captain's complete lack of awareness of airspeed, vertical speed, and aircraft performance throughout an ILS approach and landing in visual meteorological conditions which resulted in his landing the aircraft at an excessively high speed and with insufficient runway remaining for stopping the aircraft, but with sufficient aircraft performance capability to reject the landing well after touchdown. Contributing to the accident was the first officer's failure to provide required callouts which might have alerted the captain to the airspeed and sink rate deviations. The Safety Board was unable to determine the reason for the captain's lack of awareness or the first officer's failure to provide required callouts.
NTSB Aircraft Accident Report, AAR-79-2, Allegheny Airlines Inc., BAC 1-11, N1550, Rochester, NY, July 9, 1978