B738 visual approach with stab trim inop

[Lan_Morehell]

Hello folks!

In our sim refresh program for 2018 there is a following exercise for CM2:
Stab out of trim on G/A, followed by stab trim inoperative, and then... Visual Approach LYPG rwy 36 with 30kts crosswind.

This is weird as I cannot imagine a situation forcing me to perform visual with this kind of malfunction taking into account QRH advice to establish landing config early and necessity to trim manually disconnecting the clutch.
Of course in normal situation I would ask for a 10-mile final ILS. But an exercise in an exercise. Taking into account the 3.2 glideslope and Flaps 15 speed, you barely have a minute on short final to trim the AC manually. Which is not an easy task with 30kts crosswind.

I'd like to ask your opinions how to better handle this. My current thought is to establist landing config (FL15, GD) and speed early on downwind, Trim the aircraft manually sligntly nose-up so when you reduce thrust to approx 45% for final, it will become more-or-less in trim.

Is there any better option?

[RAT 5]

By a visual approach do you mean it will be a shortened circuit, or is there no approach aid? Is there anything to prohibit (terrain) a longer approach even in VMC conditions. It would certainly be an interesting challenge making a descending circuit to a 3-4nm line up with such a cross wind; much depending on if it was a head or tail wind on base. The 3.2 slope doesn't help. so it is a good idea to have the drag out and speed under control at G.S. capture.
Tell us more about what is necessary/expected for the turn from downwind to finals.

[Lan_Morehell]

Both shortened and no aids. Usually for visuals on FFS we have a terps circling restriction of 3.6 nm from threshold. Not to mention that visual approach means visual contact with the runway. So you cannot fly too fat out on downwind. SOP's dictate that you have to count 30 seconds from abeam and fly it 1500 AGL. This usually leads to to a square part of curcuit of 2.5 wide and 2.5 out from from THR. Accounting for turn anticipation, you have something like 500ft wings level and 1.5 mile straight final. Of course, in these circumstances, I think, I can make it a bit higher (2000 AGL ) and longer (use 3-3.5 miles base fron THR), But it is still not much... Due to terrain you cant make it very wide also...

We cannot use any radio aids, though the runway itself has an ILS. The only thing possible is to create a RWY extension for 3nm with 3.2 angle to use use raw data VNAV path pointer and VSD.

The wind is going to be 090/30 which makes it straight tailwind on base.

[RAT 5]

That sounds tight. Why not 4.2nm circle? Is TERPS more restrictive than PANS OPs? (It's been a long time away from the books.) 30 secs at 1500agl is also tight. 45secs is more normal. The width of the circuit is important considering the tailwind; you wound not want to overshoot finals. If you are visual with terrain why not extend. As you fly downwind I would pick a point/ ground-feature on an extended finals as a centre line reference. I'm assuming the ILS will be u/s. What about PAPI's. If there is nothing, and you feel you need it, then your RWY ext is an idea. If you are good with visual glide paths then RW THR in FIX with a radial for centre-line and a circle for what distance you want. That is just for orientation; but my guess is the exercise is to be a pure visual manoeuvre. Good practice and within capabilities.
If you are restricted to the profile you mention then a descending base leg would be required. Therefore landing configuration & speed need to be stable at the beginning that descent. You'll be cruising downwind at F5 & 58%. An idea: abeam threshold start timing and configure Geardown F15 and set N1% 45%. Speed will reduce slowly, making trimming easier, and the judgement is to reach the turn point on speed in level flight. You then start the turn and set up 7-800fpm and refine trim. From then on the adjustments will be delicate and once on centreline & slope the trim & power setting should have been found. Any small thrust changes will not need trim changes. If you make it too difficult you'll need 3 hands. That's the secret; try and keep it to only 2.

Good game: enjoy.

[Lan_Morehell]

Sounds really nice.... Thank you! " If you make it too difficult you'll need 3 hands. That's the secret; try and keep it to only 2." - explain it :)

[Check Airman]

If they're going to force you to do it as you've described, that seems like a poorly thought out training scenario, at best. At worst, it's negative training. You wouldn't do that in real life.

[FlyingStone]

Divert somewhere with an ILS, ask for a 10nm final and configure early.

If the instructor is not happy, that's some serious negative training. You wouldn't do a visual approach with no navaids, this kind of failure and this kind of wind in real life anyway, unless you would be very low on fuel.

[ajd1]

Check Airman hits the nail on the head. An over zealous Training Dept.

[blind pew]

ZRH 16 cloud break down to 1000 ft with left hand circling onto 28...(very occasionally RH which was even more fun).....
Rolling wings level below 500ft..even on a DC 10 after 11 hours in the air not a problem if you are trained for it and competent.

[RVF750]

If you hand flew a lot it would be not a problem. But as almost all Flight Ops nowadays don't want their crews to actually comfortably hand fly their aircraft it's a big ask.

As said, it's unlikely to be tidy, and almost setting you up to fail. We're only airline pilots, we mitigate risk, it's a vital part of the job. Your location gives a lot away though.....

[RAT 5]

" If you make it too difficult you'll need 3 hands. That's the secret; try and keep it to only 2." - explain it

One hand on control column, one on TL" and then, when you adjust thrust, you need trim adjustment. That was done by your thumb, but the switch doesn't work, so your hand on the TL's needs to wind the trim handle. That hand is going up-down round & round. easy with 3 hands. It's easier if you can establish a stable power/trim setting and then just make small trim changes with corrections being made with elevator, temporarily. 2 hands.

[Avenger]

Actually its not that difficult an exercise as if you establish GD F15 downwind then the trim you have is set for level flight so descending is merely a question of reducing thrust, PM can trim manually as needed. The XWC is not a pitch consideration and so ignore it and fly the normal technique in the flare. Whilst it may seem like the sortie from hell, its actually designed to see if crew appreciate the relationship between small power changes and small trim changes. Just because its a visual it does not mean you can't put in the RW ext and 3.2% glide to assist with lateral and vertical SA. Establish the power setting early and use the FPV and it should be no problem. in a perverse way the XWC means the trimming for HWC on short final is almost nil.

[Vessbot]

Is the airport in a non radar environment? If not, you can also ask for vectors to a long final.

[Check Airman]

ZRH 16 cloud break down to 1000 ft with left hand circling onto 28...(very occasionally RH which was even more fun).....
Rolling wings level below 500ft..even on a DC 10 after 11 hours in the air not a problem if you are trained for it and competent.

That doesn't seem onerous at all- if everything is working. It actually seems like fun. My objection is that in an airplane that's out of trim, you wouldn't be doing what the sim exercise is asking.

FYI, I'm not a 737 pilot.

Edit- re-reading some of the above posts a bit more carefully, what exactly is the problem? Is the stabiliser stuck, or is the control wheel trim switch inop?

[Cough]

Can you brief the PM to do some of the trimming for you? (slowly, until you tell him to stop)

[framer]

You’re nuts if you don’t:)

[RAT 5]

Disagree. Reduced finals with that wind there will be quite a bit going on with the control column & perhaps thrust, but gently. PF will be concentrating on instinctive control. Having to talk as well will increase an already high workload. It'll sound like a couple of chaotic removal men trying to manoeuvre a couch through a window: "left a bit, stop; no, bit more, no no right a bit, no; too me a bit, agh, too much, back a bit, stop; to you to you; left a touch, just a touch....ouch. WTF."
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. That will be instinctive. On a 3-4nm final it's only going to be for 1.30mins in total. Remember you will have already demonstrated that you can land with 'Stab out of Trim' and the forces there were much greater than a couple of grammes in this case.

[Lan_Morehell]

Edit- re-reading some of the above posts a bit more carefully, what exactly is the problem? Is the stabiliser stuck, or is the control wheel trim switch inop?

Both AP and CW switches inop. only manual handle-and-wheel trim.

Can you brief the PM to do some of the trimming for you? (slowly, until you tell him to stop)

Of course, but I doubt if there would be much time for that on final.

Disagree. Reduced finals with that wind there will be quite a bit going on with the control column & perhaps thrust, but gently. PF will be concentrating on instinctive control. Having to talk as well will increase an already high workload. It'll sound like a couple of chaotic removal men trying to manoeuvre a couch through a window: "left a bit, stop; no, bit more, no no right a bit, no; too me a bit, agh, too much, back a bit, stop; to you to you; left a touch, just a touch....ouch. WTF."
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. That will be instinctive. On a 3-4nm final it's only going to be for 1.30mins in total. Remember you will have already demonstrated that you can land with 'Stab out of Trim' and the forces there were much greater than a couple of grammes in this case.

The stab Out of trim is going to be introduced somewhere during a rejected landing maneuvre, followed by an all-operational RNAV approach. So by that time we barely will have demonstrated something :)

[Check Airman]

Both AP and CW switches inop. only manual handle-and-wheel trim.

Ah, thanks for the clarification. I've had this happen on a different type, both as PM and PF- where I had to use the backup trim switches on the pedestal. We flew a normal pattern both times. No need to over-complicate things with a shorter than usual final approach.

[vilas]

Not a 737 guy but it shouldn't be as bad as stabilizer stuck. Jam stab exercise is performed in other aircraft e.g. A300

[Centaurus]

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:ugh:

[RVF750]

I've known a few like that. We sent one to the CAA.... Very nice reference too....

[misd-agin]

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.

[FCeng84]

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.

[RAT 5]

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?

[Starbear]

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.