B737 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Deviation / Discrepancy - Procedural Published Material / Policy
General None Reported / Taken
Company Policy; Human Factors; Procedure
The purpose of this report is to bring to your attention a possible pitfall/oversight specific to the B-737 community. I see that the nomenclature for the Two Engine Flameout [checklist] is now titled 'Loss of Thrust in Both Engines.' I would ask that the training department re-assess this change since it can complicate an anomaly germane only to the B-737 fleet; which some of us have experienced in the past. The B-737 fleet has and is experiencing a significant delay in thrust response (up to 40 seconds) under certain conditions. During this delay time; the throttles are inoperative; there is no increase in thrust…thrust is at idle power. So ostensibly there is no thrust available during this period of extended delay; however; the only issue that must be mitigated by the flight crew is airspeed and that is managed at this point through loss of altitude. All aircraft systems operate normally and so altitude loss is the only concern. Please note that both engines are still operating; however there is zero thrust available during this delay period and as such; it would appear that the pilot is obligated to shut both engines down; lose several normal operating systems and then of course have to lose altitude as well; all of which except for the loss of altitude is self induced. You can see my concern over the new title of this checklist immediate action item. I would recommend either changing the title back to 'Two Engine Flame Out' procedure or add additional information to prevent the pilot from executing an immediate action item and possibly complicating a very simple recovery. Please note that the loss of thrust in both engines occurs more frequently than an actual two engine flameout; thus the concern and the request for relief with this procedure.
B737 Captain laments the change in the title of the Two Engine Flame Out checklist to the Loss of Thrust on Both Engines checklist. The CFM56 engines on the B737 occasionally experience a significant delay in thrust response (up to 40 seconds) under certain conditions; which may be interpreted as a loss of thrust.