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Victor Lemmi
16th Sep 2004, 14:37
Recall Items

Hi everybody!

I do not feel comfortable following the relative CList described on B767 QRH regarding this failure.

I would rather that " Stab Trim Cut Out Switches (both)...Cut Out" were a recall Item when the EICAS MSG " Unschedule Stab Trim" blinked on my panel.

Wich are your opinion?

Good Flights for all.

Victor Lemmi
FO B767 Varig Brazilian Airline

Daysleeper
16th Sep 2004, 15:17
Its a recall item on our 757s.

mbcxharm
17th Sep 2004, 01:06
It's not a recall item on our 757s but probably should be...

I think you're entitled to go for the cut out switches anyway just through airmanship.

jorgvaz
17th Sep 2004, 05:04
In my opinion the qrh procedure is so clear and logic, in order to stop the unconmmanded stabilizer motion you must first shuts off the hydraulic power to the stabilizer control module by placing both the stabilizer trim cut out switches in cut off position, then desengage the autopilot and start to investigate placing one at time to find out wich of them if the case are working not properly.

In my 757's qrh is not a recall item-

bye

spoilers yellow
17th Sep 2004, 08:36
in our QRH they are boxed memory items on both 757 and 767.

Old Smokey
17th Sep 2004, 10:51
For the B777,

STABILIZER CUTTOUT SWITCHES (Both)...................CUTOUT
Do not exceed current airspeed,

are RECALL items in response to the [STABILIZER] EICAS MSG. The associated text describes the condition as - "Uncommanded stabilizer motion detected or stabilizer is inoperative", which would appear to be equivalent to the B767 " Unschedule Stab Trim" message.

Maybe Boeing logic is common across types here, maybe not.

flying_elvis
18th Sep 2004, 15:56
Unscheduled Stab Trim Light.....the only Amber Warning that can kill you quickly. I always check the stab trim yoke cutout when I set the flaps on taxi.

Old Smokey
20th Sep 2004, 06:50
Victor Lemmi,

A post-script to my earlier comments......

I'm not familiar with the B767, but on some earlier Boeing aircraft which I've operated (e.g. B727) the stab brake prevented any further stabilizer activity if the pilot applied opposite elevator force to the stabilizer movement. Once contained in this way, the pilot could then operate the Stabilizer Cut-Out in a more leisurely manner.

IF this is so for the B767 it may explain why operation of the Cut-Out switches is not a recall item.

None
21st Sep 2004, 17:59
Boeing 767 Ops Manual Vol 2:

"The control column can be used to interrupt stabilizer trim commands. This feature allows the pilot to quickly stop uncommanded trim changes. The stabilizer trim commands are interrupted if the control column is displaced in the opposing direction."

Jetstream Rider
21st Sep 2004, 19:05
Yes, but if the autopilot is in, by the time you have got the QRH out, found the page etc the trim could be full deflection. I have tried this in the sim and would not like it to happen for real. You can control the aircraft as normal, but no autopilot and a hell of a push or pull is required. So much that my colleague had to help and I couldn't control the forces for more than about 10 mins without a break, arm wobble was a problem too.

If I saw it, I would switch them off regardless of whether it was a memory item (normally I am 100% SOP and it is a memory item in my company). If I were mistaken I could always switch them on again. Not to be confused with the 'stab trim' message though which is different.

McGreaser
21st Sep 2004, 19:51
I agree, in the sim if you do get runaway stab trim it "really runs away" if you don't stop it in time and by then even two portions of the Capt's meal won't be enough to control it or fly the a/c :} Switching off hydraulic supply to the stab trim at the first indication of runaway trim would a very good idea. I do recall though in one of the books by Mike Ray on the B767/B757 where he's totally against the idea of resetting the cutout switches one by one. Wonder why though :confused:

Stormrider
22nd Sep 2004, 00:49
Hmmm, it's not a recall item in our QRH either.

However, in the NNC section of the Checklist Introduction it states,

"The pilot flying may also direct reference procedures to be accomplished by recall if no hazard s created by such action, or if the situation does not permit reference to a checklist."

I would consider this to be one of those such situations and I'd certainly be performing at least the first two items of the checklist by recall (Cutoff Switches and A/P).

Curious that Boeing doesn't standardise it across fleets though...