B737 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Other / Unknown; Training / Qualification
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
General None Reported / Taken
Company Policy; Manuals; Procedure
The 'Engine Limit or Surge or Stall' Non-normal checklist in the 737 Flight Manual (FM) is incomplete. After guiding the pilot to the conclusion that he/she is operating with a degraded engine; the checklist fails to direct the pilot to plan to land at the nearest suitable airport; as mandated by FAR 121.565. The lack of this direction is inconsistent with the rest of the non-normal checklists in the FM; which include this directive if such action is required; and thereby creates a situation which has led to pilots in the past to conclude that they are legal to fly beyond a suitable airport.The required action is written elsewhere. According to the FOM; 'If a degraded engine operation occurs . . . diversion is required to the nearest suitable airport; in point of time; where a safe landing can be made (FAR 121.565).' The FOM continues on to define a degraded engine: 'An engine is considered degraded any time the engine thrust is reduced as a result of an emergency or non-normal; even though it may not actually be shut down.'The required action is written in the FM as well; but only in the 'Introduction' section to the 'Non-normal Operations' chapter of that manual. According to the section titled; 'Landing at Nearest Suitable Airport'; there are five specific instances where a pilot is directed to land at the nearest suitable airport. They are: fire or smoke continues; inoperative engine; degraded engine; only one AC power source remains; only one hydraulic system remains. Of those five; a degraded engine is the ONLY malfunction which does not have the direction to land at the nearest suitable as part of the non-normal checklist. Although the required action is written in the FOM; and the 'Introduction' to Non-normal Operations in the FM; it is not included anywhere in the Quick Reference Handbook (QRH); which is the primary document used inflight when performing a non-normal checklist. 'QRHs… (Preclude) the need to refer to the FM during non-normal situations.' Without a complete checklist; the required action becomes a memory action item. According to the FM; memory action items are written on the front cover of the QRH. This one is not.The FM assures the pilot that 'Non-normal checklists start with steps to correct the situation. If needed; information for planning the rest of the flight is included.' The requirement to land at the nearest suitable airport is needed information for planning the rest of the flight; and is absent.This is not an imagined threat. Years ago an incident involving this exact scenario on the 757 led the leadership to determine if the mistake of continuing beyond a suitable airfield with a degraded engine was an error unique to one crew; or if there was a lack of knowledge of the correct action required among the entire 757 pilot group. After sampling the 757-line pilots' familiarity of this subject; during training and checking events; it became evident that a lack of knowledge in this area did exist; and a remedy was needed. The 757 Fleet; in concert with the FAA; made 'Degraded Engines' a required 'Hot Topic' briefing item; and a line was added to the 757 checklist; which dealt with compressor stalls. It is my understanding that presently the 757 Fleet is the only fleet whose degraded engine non-normal checklist includes the direction for the pilot to plan to land at the nearest suitable airport.Without clear direction in the checklist to land at the nearest suitable airport when operating with a degraded engine; the cockpit conversation sounds like this:Pilot 1: ''Engine Limit or Surge or Stall' Checklist is complete.' Pilot 2: 'Complete? Did it say anything about planning to land at the nearest suitable airport?'Pilot 1: 'Nope.'Pilot 2: 'Well; if it was required; the checklist would have said so; so I guess we can continue on. Let's plan on landing somewhere where the passengers have some chance of catching other flights to their destination while this plane getsfixed.'Pilot 1: 'Sounds like a great idea.'By adding just one line of text to the checklist; this conversation will never happen; resulting in a safer and FAR compliant operation.
A Boeing 737 Captain reported that the QRH checklist does not give clear direction when operating with a degraded engine.