the learning never stops!

KC-135A TOLD Example

KC-135A

Back in 1980, when I was a copilot in the KC-135A, computing takeoff performance data meant going through a book of charts and tables and using a very sharp pencil to produce the required numbers. This took about 15 minutes for a novice, but a good copilot could crank them out in about five. I am going through one set of data here just to show how laborious it was. Once the flight was over, the set of takeoff data was checked by a standards and evaluation pilot. Errors of more than 2 knots or 200 feet would require the copilot to be retrained.


images

Photo: KC-135A Water Injection

Click photo for a larger image

Givens

You normally start with a set of givens, such as the weather, the passenger load, the cargo weight, and the fuel. In the tanker world, you might be given this scenario, where you want to take off with as much as physically possible to maximize the fuel available to offload to the receiver.

images

Photo: Givens

Click photo for a larger image

Step 1

Step 1 is to determine the target thrust setting. A "Wet EPR" means this is the Engine Pressure Ratio given the water injection system is operational.

images

Photo: Step 1

Click photo for a larger image

Step 2

Step 2 is to find a "Dry EPR," the thrust setting without water augmentation. In some situations you could delay the takeoff, drain the water, and then go. In this case, we are shooting for maximum gross weight so that isn't an option. But the dry EPR is still needed in case the water system fails after decision speed.

images

Photo: Step 2

Click photo for a larger image

Step 3

Step 3 is to compute wind componets. The advantage of headwinds are usually not used, but if they are it is without the gust. The crosswind is considered, sometimes with the gust.

images

Photo: Step 3

Click photo for a larger image

Step 4

Step 4 is can be worked to determine a critical field length given the weight, or the weight given the available runway. In this case we determine the longest possible critical field length by subtracting our line up distance from the runway length. This is the first part of this chart and it simply corrects the critical field length with the runway grade, wind, runway condition, engine anti-icing, and bleed condition.

images

Photo: Step 4

Click photo for a larger image

Step 5

Step 5 is the second part of determining our maximum gross weight given the runway length. Notice how you are making several turns in the chart where missing by one square can amplify the error so you can get your grossweight 5,000 lbs in error.

images

Photo: Step 5

Click photo for a larger image

Step 6

Step 6 is a check of the climb requirements.

images

Photo: Step 6

Click photo for a larger image

Step 7

Step 7 finds takeoff speed.

images

Photo: Step 7

Click photo for a larger image

Step 8

Step 8 finds inflight minimum control speed.

images

Photo: Step 8

Click photo for a larger image

Step 9

Step 9 ensures the crosswind is less than the maximum allowed.

images

Photo: Step 9

Click photo for a larger image

Step 10

Step 10 is another crosswind check.

images

Photo: Step 10

Click photo for a larger image

Step 11

Step 11 is a check of tire placard speed.

images

Photo: Step 11

Click photo for a larger image

Step 12

Step 12 finds ground minimum control speed.

images

Photo: Step 12

Click photo for a larger image

Step 13

Step 13 determines a transfer number for the next chart, which finds critical engine failure speed.

images

Photo: Step 13

Click photo for a larger image

Step 14

Step 14 determines critical engine failure speed.

images

Photo: Step 14

Click photo for a larger image

Step 15

Step 15 takes every number that can determine decision speed (S1) to come up with it.

images

Photo: Step 15

Click photo for a larger image

Step 16

Step 16 finds maximum braking speed.

images

Photo: Step 16

Click photo for a larger image

Step 17

Step 17 finds rotation speed.

images

Photo: Step 17

Click photo for a larger image

Step 18

Step 18 finds the ground run.

images

Photo: Step 18

Click photo for a larger image

Step 19

Step 19 finds the stabilizer trim setting.

images

Photo: Step 19

Click photo for a larger image

Step 20

Step 20 finds the approach speed for an emergency return.

images

Photo: Step 20

Click photo for a larger image

Step 21

Step 21 finds the emergency return touchdown speed.

images

Photo: Step 21

Click photo for a larger image

Step 22

Step 22 finds EGT limits.

images

Photo: Step 22

Click photo for a larger image

TOLD Card

The result of all this is to produce a takeoff and landing data card.

images

Photo: TOLD Card

Click photo for a larger image

Top