Date: 201807
Aircraft: B737 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Parked
Aircraft component: Flap Control (Trailing & Leading Edge)
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Situational Awareness
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
Result: General None Reported / Taken
Contributing factors: Procedure
Primary problem: Procedure

Narrative: The 737 fleet newsletter has; in the past; advised pilots experiencing an inadvertent flap torque brake activation to execute a go around and run the appropriate QRH procedure (Flaps--Trailing Edge Flap Disagree). The newsletter chided pilots for not automatically making the go around decision. I think this blanket one-size-fits-all guidance needs rethinking for at least three good reasons.First; it is not unusual to be dispatched to an airport wherein the Dispatch remarks require a bleeds off approach; flaps 5 go around. A torque brake lockout with flaps stuck at 5 degrees makes the go around performance questionable. I envision an approach at night in icing conditions into an airport surrounded by high terrain; and the pilot trying to execute a successful go around with flaps stuck around 30 degrees. Throw in an engine failure during this sluggish go around; and the consequences are dire.Second; the normal call outs for a routine go around begin with calling for flaps 15. I can see the flaps being oversped as the pilots muddle through a procedure never practiced; with flaps stuck nearer 25-30.Finally; the flight manual allows a pilot to land flaps 15 without exercising due diligence on stopping capability should an engine fail on final approach. With an engine failure on final; the pilot may continue the approach by increasing thrust; re-bugging to a higher speed; and selecting flaps 15. There is no prohibition against continuing the approach--even to a high altitude airport; a short runway; or a terrain critical airport; or all three combined. For those who would argue landing with a flap disagree due to torque brake lockout represents an unstable approach (not configured as briefed); I submit the engine failure on final scenario trumps that hands down: one must raise flaps; deal with resulting sink rate; achieve a higher target speed (lower the nose more); add full power on the working engine; and counter the asymmetric thrust. Totally unstable.I recommend company revisits the guidance that a go around is appropriate in all circumstances with a flap torque brake lockout. Perhaps the flight manual could advise that a go around for a flap torque brake lockout during a mandated bleeds off; flap 5 go around approach is inadvisable if flaps are stuck much beyond flaps 5. I'm not even sure if a normal approach predicated on a flaps 15 go around is capable of adequate terrain clearance should the go around be executed with flaps much greater than 15 degrees in certain circumstances. At any rate; landing with flaps stuck between 15-30 seems no worse than landing flaps 15 following an engine failure on final approach; particularly when landing performance issues exist.




Synopsis: A B737 Captain reported that procedures for flap torque brake activation should be reviewed.