B738 visual approach with stab trim inop
[quoteStab out of trim on G/A, followed by stab trim inoperative, and then... Visual Approach LYPG rwy 36 with 30kts crosswind. ][/quote]
Sounds like the instructor is the type of personality that enjoys loading you up with the most unlikely combination of "events" and then blames you when you struggle to cope. Interestingly I have yet to see the simulator instructor who will take a control seat and attempt to demonstrate such rubbish combination of events. They will avoid that like a plague and claim it is not their job to demonstrate. Truth being these sort of personalities don't dare to demonstrate for fear of loss of face when they stuff up
Sounds like the instructor is the type of personality that enjoys loading you up with the most unlikely combination of "events" and then blames you when you struggle to cope. Interestingly I have yet to see the simulator instructor who will take a control seat and attempt to demonstrate such rubbish combination of events. They will avoid that like a plague and claim it is not their job to demonstrate. Truth being these sort of personalities don't dare to demonstrate for fear of loss of face when they stuff up
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RAT 5 - “If the beast is close enough in trim and on speed with stable thrust then PF should be able to cope with the tiny temporary changes in trim caused by thrust with elevator.”
Bingo. The smaller the thrust corrections the smaller the thrust induced pitch force changes will be.
Bingo. The smaller the thrust corrections the smaller the thrust induced pitch force changes will be.
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Pitch Control Power Design
For commercial aircraft that have the conventional arrangement of an all moving horizontal tail (stabilizer) and attached elevator surfaces, demonstration of sufficient control power for continued safe flight and landing with the stabilizer stuck at any "normally encountered position" is a requirement. There may not be sufficient pitch control authority in the elevators alone in the event of a stabilizer that is stuck in a position that is grossly out of trim.
For this reason, monitors to detect uncommanded stabilizer motion and provide rapid automatic shutdown of power to the stabilizer trim motors are common. Another fallout of this is that failure combinations that disable the stabilizer and significantly reduce elevator control authority must be shown to be extremely improbable.
It seems to me that the scenario described is more a matter of whether or not the airplane is left with sufficient control power to continue with safe flight and landing, not a matter of pilot ability to handle airplane path control. Of course, procedural limitations on thrust and flap that impart significant pitching moments must be honored.
For this reason, monitors to detect uncommanded stabilizer motion and provide rapid automatic shutdown of power to the stabilizer trim motors are common. Another fallout of this is that failure combinations that disable the stabilizer and significantly reduce elevator control authority must be shown to be extremely improbable.
It seems to me that the scenario described is more a matter of whether or not the airplane is left with sufficient control power to continue with safe flight and landing, not a matter of pilot ability to handle airplane path control. Of course, procedural limitations on thrust and flap that impart significant pitching moments must be honored.
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It seems to me that the scenario described is more a matter of whether or not the airplane is left with sufficient control power to continue with safe flight and landing, not a matter of pilot ability to handle airplane path control.
The OP pilot suggested this was an recurrency training exercise not a test flight. It seems there might be 3 box ticking exercises being combined into one scenario. Now how can we tick off a 'flight control' & 'x-wind' landing' & an 'out of trim landing' all in one? Good game. It might be a confidence boost if you survive or a total confidence cruncher if you don't. And what does the erstwhile instructor do if you go off the edge? Will it be a debrief & demo then more training to achieve said goal, or is it a S- in the training file and move on to the next box? And given that there might be little time for that what will he do if you decide, correctly to GA. Will there be time for the correct diversion to a more sane place?
The OP pilot suggested this was an recurrency training exercise not a test flight. It seems there might be 3 box ticking exercises being combined into one scenario. Now how can we tick off a 'flight control' & 'x-wind' landing' & an 'out of trim landing' all in one? Good game. It might be a confidence boost if you survive or a total confidence cruncher if you don't. And what does the erstwhile instructor do if you go off the edge? Will it be a debrief & demo then more training to achieve said goal, or is it a S- in the training file and move on to the next box? And given that there might be little time for that what will he do if you decide, correctly to GA. Will there be time for the correct diversion to a more sane place?
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Leaving aside (although one shouldn't) the concept of this ridiculous scenario, I believe there MAY be some misconception here.
The OP talks about a "visual" approach after a GA in this scenario.
This is not a circling approach therefore neither TERPs nor PANS OPS threshold distances come into it. Neither should there be a requirement to fly a "visual circuit" per se. When you are cleared for a visual approach, unless it is specified via LH/RH downwind or L/R base etc. it is entirely up to the pilot to manoeuvre the aeroplane with terrain separation his responsibility and no specific timings 45secs or otherwise are applicable (only those prerequisites already mentioned such as keeping the ground and RW where applicable in sight and therefore, terrain permitting, it should be possible to extend the final approach leg. A quick look at the charts suggests there is adequate space for this.
Someone already mentioned it was their SOPs to fly at 1,500'agl and time 45 secs etc. IF the company really mean that for every visual approach then all bets are off regarding my comments above, or are they in fact quoting the standard training circuit numbers which are after all only there for guidance, a training circuit is really a useful tool for handling and training but not a requirement for a visual approach.
All of the mentioned ingredients in the quoted scenario, when combined are simply some misguided fool's version of good training.
I may be wide of the mark here but I find it is regularly misunderstood that a visual approach must be flown as a visual circuit, especially in the simulator.
Study the charts carefully, glean all the info you can especially distance from abeam RW and threshold to terrain and formulate a plan for a visual approach. Be creative but sensible and don't be hamstrung by irrelevant data. Finally make sure you can defend/justify your plan or actions if challenged.
The OP talks about a "visual" approach after a GA in this scenario.
This is not a circling approach therefore neither TERPs nor PANS OPS threshold distances come into it. Neither should there be a requirement to fly a "visual circuit" per se. When you are cleared for a visual approach, unless it is specified via LH/RH downwind or L/R base etc. it is entirely up to the pilot to manoeuvre the aeroplane with terrain separation his responsibility and no specific timings 45secs or otherwise are applicable (only those prerequisites already mentioned such as keeping the ground and RW where applicable in sight and therefore, terrain permitting, it should be possible to extend the final approach leg. A quick look at the charts suggests there is adequate space for this.
Someone already mentioned it was their SOPs to fly at 1,500'agl and time 45 secs etc. IF the company really mean that for every visual approach then all bets are off regarding my comments above, or are they in fact quoting the standard training circuit numbers which are after all only there for guidance, a training circuit is really a useful tool for handling and training but not a requirement for a visual approach.
All of the mentioned ingredients in the quoted scenario, when combined are simply some misguided fool's version of good training.
I may be wide of the mark here but I find it is regularly misunderstood that a visual approach must be flown as a visual circuit, especially in the simulator.
Study the charts carefully, glean all the info you can especially distance from abeam RW and threshold to terrain and formulate a plan for a visual approach. Be creative but sensible and don't be hamstrung by irrelevant data. Finally make sure you can defend/justify your plan or actions if challenged.
Last edited by Starbear; 25th Jan 2018 at 02:32.
