Originally Posted by Notanatp
I've read one account of the test that said all three test pilots recovered the airplane if it was assumed they recognized the problem within 3 seconds (the time to respond to an autopilot runaway pitch trim). The FAA wasn't satisfied with that so it ran additional tests were it allowed the failure to go longer before being recognized, and one of the three pilots either couldn't recover or didn't recovery fast enough. My understanding is that it was on the basis of this addition test where it was assumed that only an exceptional pilot would have recovered, therefore, the catastrophic classification. Has anyone else seen this account, and if it is correct, then doesn't it sound like this is rigged against Boeing?
Further to GordonR’s reply, I would add that the regulatory assumption of a 3-second response time to trim runaway is highly questionable. The operating data manual for my (military) type assumes a 3.5-second pilot response time for loss of thrust during takeoff, and that’s a readily-diagnosed failure where the pilot can reasonably be assumed to be in a state of optimum vigilance with hand on throttle, ready to cut. Contrast that with trim runaway on a 737, where the first second or two could easily be rationalised away as speed trim, leaving only another second to complete the diagnosis and instruct PNF to cutout the trim. Then add more time for PNF to process this startling instruction and find, unguard and flip the switches. Then maybe add more time for CRM SOPs (“state the malfunction”... “memory items”...), depending on company culture and crew experience. The Mentour Pilot video from months ago may have exaggerated this grossly (10:10 to 11:25 at the link below), but whichever way you look at it, an allowance of only 3 seconds to isolate the trim implies an
exceptionally optimistic assessment of human startle response.