MFS has queried a comment I made here (and now have deleted) regarding certification aspects of reverse thrust .. as I can't lay my hand on the regulatory derivation, it is best that the comment be removed to avoid confusion. It may be that my memory has placed the requirement in the wrong jurisdiction ...
Didn’t dig out any regs John but from the BKK overrun report
Certified landing distance = from 50 feet above the landing surface in the landing configuration at an airspeed of 1.3Vslg to where the aircraft comes to a stop using maximum wheel braking
Landing distance (Dry) = 1.67*certified landing distance
Landing distance (Wet) = 1.15*dry landing distance
Reverse thrust is not used in these calculations because it is considered as an additional safety factor.
Letter from Boeing to QANTAS July 1997
…..Additionally, some of the techniques we have heard discussed, such as reduced landing flap settings and the use of idle reverse thrust, have a negative impact on airplane stopping performance. Therefore, these techniques are not recommended as standard practice.
Extract from report into QANTAS overrun Bangkok 23 September 1999.
The flight crew did not select (or notice the absence of) full reverse thrust. The use of full reverse thrust would have substantially reduced the landing distance on a runway with poor braking action. The failure of the crew to consider the use of full reverse thrust during the landing roll appeared to be primarily due to the high workload they were experiencing. Had the crew received more training in the importance of reverse thrust on water affected runways, or recent experience in the use of reverse thrust, it is reasonable to expect that the crews awareness of the importance of reverse thrust (and therefore the likelihood of them selecting full reverse thrust) would have been greater.
QANTAS at the time had no simulator exercise requiring the use of full reverse thrust. Idle reverse was the ‘standard’ procedure.
Letter from Boeing to QANTAS April 2000
Boeing does not consider the standard practice of going to reverse idle (idle detent) only to be patently unsafe, but does think that it reduces the existing performance margins. It is acceptable pilot technique to do this (using good judgement) as an exception to the normal procedures when landing on a long, dry runway. We perceive, however, that there is a human factors issue of developing a habit pattern of not using reverse thrust beyond the idle detent. The pilot may then fail to respond quickly when such reverse thrust is needed during an RTO (rejected takeoff) or landing in some type of performance critical situation. We therefore do not provide a “No Technical Objection” for this as a standard operating policy.
If the reverse idle technique is adopted, it should be taught as the exception rather than the rule. Further, we would encourage simulator drills to be incorporated into the transition and recurrent training courses that would require pilots to use judgement to use full reverse thrust as the best successful means of stopping the airplane. This would periodically reinforce this concept of using that capability when needed.
Do the Boeing manuals not advocate the use of full reverse thrust as the BKK report suggests?