Questions you had never asked before about B737

[JammedStab]

Originally Posted by Denti

To be honest i don't use 2 all that often, but it is sometimes useful. 10 and 25 on the other hand are normal take off flap settings and therefore used quite often. Much less often during approach though, although it can be sometimes advantageous to do so.

Flaps 2 was used a lot on the -200 in my experience for takeoff. Compared to flaps 1, it gives several thousand extra pounds of capability at some airports depending on the situation. Also, it gives about 5 knots lower v-speeds which always felt kind of fast to me.

For the newer types, I guess, it is just a holdover from the old days.

[medflyer]

CWS P

I disagree that CWS is a waste. It is merely a tool that can be useful in some specific situations.

For example, I like CWS P when the NG is doing the hobbyhorse routine in a VNAV climb. It will still level off (capture an altitude) in this mode. If you enter the mode without selecting N1 on the A/T then the power will come back to hold the selected speed. If you leave it in speed it will function like V/S, which has its place too. Although some shy away from full CWS as it will sail right through an altitude selected on the MCP, there is actually a way to ensure this will not happen: breaking out the autopilot through pressure on the controls in pitch and roll will get you into CWS but with 'CMD' on the FMA vs 'FD', which is what you will see if you get to CWS by simply pressing the button.
FD= no alt capture.

[ImbracableCrunk]

Although some shy away from full CWS as it will sail right through an altitude selected on the MCP, there is actually a way to ensure this will not happen: breaking out the autopilot through pressure on the controls in pitch and roll will get you into CWS but with 'CMD' on the FMA vs 'FD', which is what you will see if you get to CWS by simply pressing the button.

Or you could just de-select the current V mode. Much less muscle-y.

[medflyer]

Agreed, however that only gets you CWS P, not the full CWS experience

[ImbracableCrunk]

The only time I'd use full CWS would be severe turbulence.

[Tom!]

I also have a question that has been bothering me for a while:

In the case of a loss of all generators (dispatched with APU INOP) and not recoverable.

Apart from a dozen other things you obviously also lose the elec stabtrim. Having a look at the checklist it says to land with flap 15. But since only half of you anti-skid system is working (inboard only?) it seems to be a better idea to land with normal landing flap 40? (flap indicator not working as well)

Establish and manually trim it out on long final with F40 and be careful in case of a go-around with the trim requirement, or follow the stabtrim INOP NNC and go with F15 and taking the extra speed into account for the LDR with partial anti-skid.

The loss of both generators checklist doesn't seem to have a preference.

[No Fly Zone]

Say WHAT??

From the original: "To start with, I have an electrical question regarding its electrical system:"

I'm certainly glad that your question about the 'electrical system' was an 'electrical question and not perhaps a hydraulic question. Whew . That was a close call!

More seriously, I hope you received a response that you understand.
(Tip that may help: read it out loud, even to yourself, -and before pushing the Send, Publish or Post buttons. Been there and done that. Better luck next time.

[ZFT]

Was it a bottle of red or white wine?

[stilton]

' On Britannia Airways 737-200s only the Captain had HDG SEL. The F/O only had CWS in both lateral and vertical axes. Passing the Command Course meant both a pay rise and the luxury of HDG SEL! Alt Hld had to be manually engaged on reaching assigned level, having reduced the rate of climb/descent using CWS. No V/S mode either, but we did have VOR/LOC. All selected through massive rotary switches which engaged with a satisfying clunk. Ah...those were the days!
Matey is offline Report Post Reply'



Sounds exactly like a B727

[OhNoCB]

Why no check valve from the APU bleed to stop back pressure?

[FlyingStone]

My FCOM shows that there is one...

[OhNoCB]

Hmm mine shows that there isn't! Have just double checked to make sure. Wouldn't be the first time that I have pondered questions arising form this FCOM which have been answered by better manuals.

[IFixPlanes]

I Hope you accept the AMM (Aircraft Maintenance Manual) as an "better manual".
All B737 (100-900) have a check valve in the APU bleed line.
In addition: I know it out of (more than) 25 years as a mechanic, working on this aircraft.

[ManaAdaSystem]

I want to know what I am supposed to do with the yaw damper indicator?

[IFixPlanes]

One thing is to check the system on ground during taxiing. You have a short movement in opposite direction the airplane drives in a curve.

[BOAC]

Back in 'the old days' (73-2) it used to be part of the instrument checks during taxy ("What are they....?")

[Denti]

I want to know what I am supposed to do with the yaw damper indicator?

It's not there anymore in newer planes, so i guess it can be seen as superfluous information.

[ManaAdaSystem]

Yaw damper switch on, YD works. Switch off, it doesn't.
Probably why they removed the instrument. I have never used it for anything.

When you did the instrument scan, did you check the instrument or the system?
What did you look for? It moved! Thank God!

Have any of you found the two leading edge flaps on each wing?
I must be blind because I can only find one. I've been puzzled about this for years, but I'm scared it's just me who can't find the other one.

[BOAC]

If you are asking as a pilot and you HAVE an indicator, what does your company manual tell you to do? If nothing, then happily ignore, stop worrying and return to blissful ignorance?

[TURIN]

Yaw Damper Indicator was used every night during the Daily Check. Or was it Weekly? It's been a while.