blzr said:
You guys ever use the TR's during taxi? (just the bucket, no reverse). We used them for the last brake cycle and got 300 more landings out of our brakes than before. 'Course we only weigh 24k as opposed to 50-60k.
The question is this: how long did the engine last by doing it?
Of course you'll increase brake life by using TRs. That goes without saying. The question is that over the life of the plane, are you going to still come out ahead if the engine is replaced a year earlier?
It may vary by engine type, aircraft type, and the type of operation. There may be some operators who benefit more by using TRs than brakes or vice versa. I don't have hard numbers for you, other than what the manufacturer has told me, and I admit that doesn't make my evidence any more than anecdotal. Again, the way I look at it is the same way I drive my car: that I downshift multiple times to help my car stop, and it will, undoubtedly, increase my brake pad life. However, I'll have to replace the clutch sooner, which is much more expensive and labor intensive. So rather than downshifting, I just put the shifter to neutral and use the brake pads.
As an aside, our procedures preclude me from using TRs during taxi. When I flew for another company, both their manufacturer and the company policy was to never use TRs during taxi unless an emergency dictated its use.
they wouldnt make it if it wasnt supposed to be used.
Just because it's on the aircraft doesn't mean you should use it on every landing, or to its fullest potential. My engines have 110% power available, but we typically use 90% for takeoff. Why? It saves engine life, for a negligible loss in safety buffer. That doesn't mean I wouldn't use absolute firewall power when it's necessary, but I limit use of full power until circumstances where it is necessary to take advantage of it.
TRs are put on aircraft as another method of stopping the aircraft, particularly effective on slick or icy runway surfaces or in the case of brake failure or asymmetry. Yet the landing numbers for my aircraft are calculated without even putting them to idle reverse thrust, much less full reverse. Just because they are installed does not mean that the manufacturer intended their full use at every possible opportunity.
Again, I use reverse thrust in a number of circumstances. When landing in EYW, for instance, or on 26 in PHL. Or when traffic is crawling in behind us in LGA. Or on icy or slippery runways. I don't, however, run the thing at full power in reverse on a dry, 10,000 foot runway with nobody behind me. Again, cost aside, I don't like having my head buried in the seat back pocket in front of me as I occasionally do when riding in the back. I would hope that anybody with enough training to be sitting in a jet airplane could come up with a better reason to do something than "it's there."
