What does this do?

[ditar]

Sorry for the lousy photo quality, but can someone please tell me what the big knob with the arrow does, or what it is supposed to do? Turning it doesn't seem to have any effect. Nobody I work with seems to know either.

[ETOPS]

Have you asked the passengers? One never knows.

[iflyforpie]

To set the rising runway?

[stmymdy]

I probably wouldn't touch that if I was you..that's the ejection seat..

[The Old Fogducker]

The first thing I'd do is to look in the manual, but I assume you've already went looking for a manual and realized there isn't one, although there certainly should be, since its part of the installed equipment, and you should have been taught how to use it.

Now that I've got that rant out of my system, I can't be certain of the Flight Director model after all these years, but I think it looks like one of the Sperry autopilots and its used to set the aircraft bars so they split the horizon line to compensate for parallax and differing attitudes for different power settings, speeds, and loads.

It should move, or its unserviceable.

I'd make some enquiries of the Chief Pilot and if he didn't know, then its a prime time to hit him up for a supplement for the aircraft manual.....which is where it should be.

OFD

[BushCaddy]

We had basically the same setup in the Jetstream31.

As far as we could tell it didn't do anything; just gave us pilots something to play with when we got bored!

[Meatservo]

And then come back here and tell us what it is... I'm genuinely curious myself. You would think a larger-than-average knob with a big arrow painted on it would be fairly important. OFD's guess is as good as mine, except it seems to have several discrete settings, as if it were a selector rather than an adjustment knob. I'm going through my pictures to see if any of the planes I flew that had flight directors also had the same knob... I don't think they did. Maybe look in the manual first before asking the chief pilot, OR, tell him it doesn't seem to be working without admitting you don't know what it is. That way later when you find out what it is you can pretend you knew all along.

I flew for a company in the early 90s that had an otter with a great big red button smack in the middle of the copilot panel. The button was surrounded by a painted yellow-and-black stripey square. Nobody knew what it was and nobody pressed it to find out.

[snoopy]

Unless he or she reads AvCanada...... busted! LOL

Is there a model inscribed on the face of the unit? Did you ask maintenance about it? If there is no model inscribed on the face, and you find a helpful mechanic, he or she may be willing to pull the instrument and read the label on the back. Alternatively, you could contact a reputable avionics shop. If you dig around, you can usually still find an oldtimer with experience and knowledge on older systems that may be able to help identify rogue bits & pieces.

Cheers,
Kirsten B.

[Lost in Saigon]

I can't remember which aircraft it was, but there was a knob to adjust the Flight Director bars for the pilot's eye height. Could that be it? Maybe it's been disconnected?

[lost]

Have you tried turning on the flight director without the alt. hold? IE in a descent or a climb and then turning that nob? It is possible that that is what its for, setting a target pitch in the flight director.

[Liquid Charlie]

The chicken legs -- actually much better flight director than a V-Bar - it could be the manual pitch control - if you have pitch sync or the ability to manually adjust the pitch elsewhere this knob will be deactivated.

[Intentional Left Bank]

If you look on the detailed W&B report, you should find the exact model name or number of the instrument. From there, google is your friend.

[ditar]

The autopilot does have a separate control for adjusting pitch, so perhaps the knob has been deactivated as Liquid Charlie suggested. I've asked every other captain, nobody has a clue. Even the veterans say it's never done anything. I did look in the AFM but perhaps I missed it. I will do some more digging. It'll have to wait a week though because I'm on days off.

[V1CUT]

only thing i can find


http://www.f-106deltadart.com/cockpit/i ... ts/ADI.jpg

V1

[InTheGame]

Very simply... it does absolutely NOTHING on Jetstreams. British Aerospace BAE / Handley Page I believe out of Britain when building Jetstream aircraft ordered Attitude indicators for the aircraft all the supplier had on hand were these units ( built for another purpose/ aircraft, military I believe). These units were intended for other aircraft where that knob was used for something can't remember what but used for nothing in the Jetstream . It was simply Cheaper to put these units in then order ones without the knob. So in Jetstreams the knob is connected to nothing and serves no purpose.
There are some instructors at FlightSafety in SEA that can give you a history of it and possibly the a/c they were originally intended for sorry I cannot remember.

[ahramin]

InTheGame is exactly correct. That knob is part of the flight director controls on the BAE 146. The same AI was used in Jetstreams to save money but the flight director is different and does not use this knob. Some of these units have found their way into other aircraft as well. It does not do anything (unless you are flying a 146) and not knowing what it does (nothing) will not render the aircraft unserviceable.

How would you write that up exactly? "The knob that doesn't do anything isn't working. Nor is there a manual to tell me how to make it not do anything."

To be honest, I have been known to finish off my checklists with the following:

Knob that does nothing ......................... Set

Some find it funny. Others not. Averages.

[. ._]

To be honest, I have been known to finish off my checklists with the following:

Knob that does nothing ......................... Set

I'd definitely confirm that.

[Big Pistons Forever]

How would you write that up exactly? "The knob that doesn't do anything isn't working."
.

Easy

Rectification " The AI knob that does nothing ground function checked. Non functionality verified, unit function checked servicable."
signed ACA XXX , #$^^$##^&**&^^ (illegible scrawl purporting to be the signature of AME)

[MrWings]

So if one day you turn "the knob that does nothing" and somthing happens, doesn't that make the knob U/S?

[Big Pistons Forever]

So if one day you turn "the knob that does nothing" and somthing happens, doesn't that make the knob U/S?