B737 autopilot
 

I am doing some research for out training dept., and would like collect SOP's from various colleagues. The family of B737 doesn't matter, classic or NG.
When do you engage A/P on departure, 2 engine G/A, engine failure on takeoff, SE G/A?
Boeing says the A/P is available after 400'agl and is designed to reduce workload. Who uses it to the design capability?

many thanks,

A/P on departure:
When N1 thrust mode engages (1500').

2 engine G/A:
After ALT HOLD, or when flaps are up.

Engine failure on takeoff & SE G/A:
When flaps are up and after P.M. has engaged level change and maximum continuous thrust.

Hope this helps.

hmm why to fly the whole 2 enigne GA by hand in an busy area of traffic? can you explain that?

cheerio

Above 400' we put A/P in on normal departure.

2-engine DEP and G/A: 400'
EFATO and SE G/A: flaps up

British NG operator

Cheers

P

Cant explain, just company procedures for the NG, earliest is when flaps are up.

Recommended to handfly the aircraft until at least 10.000', with or without
F/D unless weather/traffic/fatigue issues.

Never heard of an airline where on B737 you put on the autopilot at 400' already. Are they joking?!

If the environment is busy, then the autopilot probably goes in after 500' (but before 1000') just to keep the workload sensible for the other guy. London, New York, etc.

If it's less busy, then I like to fly the departure using normally LNAV/FD, or until vectors put us on a straight line, or we get held at an intermediate level for a while. Preferably up to 10000'. I include it in my brief normally.

I do know some people who chuck the autopilot in as soon as possible, irrespective. I haven't managed to get bored of flying yet.

Not joking.

From Boeing:
"The autopilot is certified to allow engagement at or above 400 feet AGL after takeoff"
(737-600 - 737-900)

If you fly 'all types' it might be worth having a look through your FCTM. . .

400' is normal for most airlines I have flown for, thats if you want to.

Folks: many thanks for the replies. What I'm really interested in, and some have hinted at it, is why the a/c is certified to engage A/P above 400' agl on Dep or G/A, but some airlines choose to wait until Flaps up and thus increase worK load and IMHO reduce safety in busy TMA's.
Further, why do some engage A/P at 400 on 2 engines, when life is normal, but wait until flaps up on SE when life is non-normal?
And please dont' say becasue our SOP's say so. That is because your current C.P wants it that way. It is not the way Boeing designed the a/c. If there are any Boeing T.C's out there will you please enlighten us. It is not possible to get a direct reply from Boeing; it has to done via the company, and they are not always responsive to radicals.

To those who wish to aviate, I too endorse hand flying, when appropriate, to all levels. I've had F/O's who've never hand flown above FL100. Soon cured that; no problem. One day it might be necessary. RVSM is not the place for it though; but a u/s A/P should not ground the a/c.

5150,

I do know the FCTM...
What I mean is that I know of no airline where it is SOP to engage autopilot on its minimum engagement altitude.
Remember that automatics can do faulty things, and that the autopilot is prone to "peculiarities" on the classics.
That said, in environments like JFK, Heatrow etc. I put on the automatics after 1000' as this is our company minimum, but keep guarded yoke/throttle until 10.000'.

Never put full trust into automatics, and remember, if in doubt what it is doing, disconnect and fly the aircraft.

RAT

Possibly for commonality across different fleets?

PP

Thanks for that. . . . . .

Hi Rats

"Further, why do some engage A/P at 400 on 2 engines, when life is normal, but wait until flaps up on SE when life is non-normal? "

One answer is that when SE if you engage the a/p too early you might get a descent just when you don't need it, the a/p will attempt to maintain a speed rather than the altitude. Once in altitude hold at 'up speed' ( ie flaps up) the a/p is engaged. I guess the a/p isn't as sophisticated as we'd like it to be.

FGL:

That last answer has me foxed. The A/P will be engaged with he a/c climbing. The AFDS will maintain the speed at which the engine failed V2 - V2 + 15. This is done with pitch. It should do no worse than level off to accelerate. Hand flying the F.D. will do exactly the same.

When the Flaps are UP, after an MFRA or 1000'agl, you will likely be <2000'agl at nominal ATOW"s. Thus you will not be in ALT HLD.

PP: Commonality across fleets? When discussing things with an Airbus TC, who knew nothing of Boeings (and I know litle of Airbuses) he was astounded that common airline SOP's on Boeings were so archaic with A/P use on departure with non-normals e.g. engine failures.

Question: A/P engaged on departure at 1500'; not yet Bug UP and accelerating to retract flaps; engine fails. Do you disconnect the A/P?

Answer: I hope: No. You apply rudder to stabilise the a/c, BUg Up and retract Flaps and climb to suitable altitude.

If this is OK, why not engage the A/P earlier, say 1000', with an engine failure at lower height or speed? It is so certified. Why do we down-grade the a/c to a Low Tech version of a High Tech a/c? We use the automatics and most other things within their limitations and the way they were designed, so why not in this case? It has often seemed to me that SOP's are carried over from old generation a/c to newer ones to suit company philosophy, which has inertia. No-one questions it and so it stays. It is only when a whole new type of a/c arrives that minds open up. I saw this in an old company of mine with an old tech Boeing a/c. It was Flaps Up A/P engaged. The A/P was certified for 400'agl and was so used by a later operator I flew for. The first airline then bought a brand new high tech Boeing. The first LTC's had only Boeing sim experience and a few sectors in the USA. It was their first LNAV VNAV computer a/c. It was a 20 year leap in technology from what they were used to. The new SOP for the first year was A/P on at 400' and watch what it did. Let the a/c teach the pilots what it wanted to do. Meanwhile the old a/c was still flown in the old way.
I flew B767 for another airline, my 4th on type, and the SOP manual had some oddities. It had been writen by and old company pilot who had been on B707. Guess what; "if it was OK for that beast it was OK for this one". Same c@&p; hand fly engine failures including complicated emergency turns, plus other very non B767 procedures. I wonder what the insurance boys will have to say if you pile in on departure with a non-normal hand flying when the A/P was available? Following orders Guv!

I have my thoughts about this , but as I said, I'm looking for some real technical reasoning why so many do it the way they do, and do not make life easier.

RAT 5,

my copy of the FCTM states that "the autopilot is FAA certified to allow engagement at or above 1000 ft AGL after takeoff" (300 - 500) and "at or above 400 ft AGL (600 - 900)".

The UK CAA also says 1000ft for the 300 - 500, don't know about the NG.

Because of this the family of 737 probably will make a difference to company SOPs.

I meant across Boeing fleets, as per excrab's comment.

Rat5, just to clarify, once in level flight , accelerating towards 'up speed', speed protection can actually give a descent.
When on a S.E missed apprch we climb to accel alt, then accelerate by calling for up speed. At high GW this is virtually a level segment. It is during this portion that a descent can occur.
Used this in 3 companies on the 737.

[QUOTE] but some airlines choose to wait until Flaps up and thus increase worK load and IMHO reduce safety in busy TMA's. /QUOTE]
What's the problem - are you frightened of a little bit of hand flying. Reducing safety is absolute rubbish. One dark night in a thunderstorm you will need hand flying skills and if you are a total automatics monkey then you should not be flying.