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shon7
10th Apr 2002, 19:55
How soon can one engage the autopilot after take-off? What is the normal procedure?

DustDevil
10th Apr 2002, 20:09
A320 : autopilot can be engaged : at 30 ft AGL if Speed Reference System available, or 500 ft min. without speed guidance.

Pegasus77
10th Apr 2002, 23:11
Hey Shon... Although I like your questions... I'm just wondering... writing a book or a filmscript or something?

P77 :confused:

bcp
10th Apr 2002, 23:11
Lets set the scene - FO doing his command training.

After 1st flight with training captain, debreifing starts and training captain thinks all is going well, however points out that after take off the sooner the a/p is engaged the better, gives you more time to keep an eye on instruments, freq changes etc.

Debreif after 2nd flight (with different training captain) has the opinion all is going well, however don't be so fast to engage the a/p - remember you are a pilot and an aviator, not a computer guy - fly the plane first and when all is well and established on climb out engage the a/p then.

Just before pushback with 3rd different training captain the up and coming FO asks "At what stage of the departure would you like me to engage the a/p Sir?"

3rd Training Captain reply "How in the hell do you expect to get a command if you dion't know when to engage the a/p".

Pegasus77
10th Apr 2002, 23:30
Do I hear some personal frustration sipping through, BCP?

In my company we have a simple rule about engaging the autopilot on the A320: not before 100ft and only after 5 seconds after liftoff.

The rest is pilots discretion.

Think of a good reason to fly manually and fly manually; if you think you have a good argument to fly automatically, engage the a/p.

IMHO there is no standard rule about where to engage the a/p; it is situation-dependent. If the trainings captain has a good argument why to wait with the a/p, you could listen. Only stating "you're an aviator" is not a good enough reason for me.

Factors in deciding whether to engage earlier or not could be: weather (maybe you want to climb faster than is programmed), delay (speed up earlier than programmed), difficulty of departure (to keep an eye on tracking), noise abatement (a/p can or cannot follow the SID more exact than you depending on type of a/c) etc etc.

As an example of engaging earlier I take a Moscow-departure, where the PNF is busy changing frequencies, and you as PF can set the FCU, instead of, when flying manually, all the work to be done by the PNF.
An example of engaging later could be a regional airport with a lot of buildups in the departure path, and a very low amount of traffic.

I think the comment of your 3rd captain makes most sense of all: if you wanna be a captain, you'd better have an opinion!

P77

bcp
10th Apr 2002, 23:58
Settle down Pegasus 77,

This happened to a fellow pilot (friend) of mine many many years ago. He dined out on the story for years, and still does. It was related back to the three captains over the years, who all found it a good laugh at the end of the day.

My reply to the post was probably not in the correct section of the forum, I was trying to give a few a laugh with the lighter side of aviation.

Pegasus77
11th Apr 2002, 00:14
Ah... well at least I took you seriously :D :D
Didn't read your post that way... sorry! :(

But I'll leave my post above unchanged, because it might answer the question of Shon7.
No hard feelings, bcp?!

P77

shon7
11th Apr 2002, 01:26
Hey Pegasus77 - Thanks for your replies. In response to your question - no I am not writing a book or a film script but these are questions that I have wanted to ask pilots for the longest time but never could. Also I have seen the books and resources around but have never been able to find these answers.

For example: when do you know how to flare a 747 and can you feel it etc- which I posted in the last post.

Thanks once again to everyone for all their replies. The questions will keep coming. In fact I think I will post one now.

Sopwith Pup
11th Apr 2002, 01:58
Shon7..... there are two ways to flare a 747. One is to do it with visual cues and the other is to listen to the Radalt call out giving you feet above runway.
Oh I forgot the third method, when the other pilot flinches it is time to flare, the last usually gives a firm arrival!:D

411A
11th Apr 2002, 01:59
Well, just ask the TriStar pilot...he (or she) can engage the autopilot on the ground (CWS) and then commence the takeoff....this is not possible with L1011 aeroplanes on the British register as the ARB (CAA) decided that this was not a good idea...which begs the question...what do they know about a US designed aeroplane....answers on a postcard.
Re-engineering the wheel comes to mind.
Minds stuck in the Trident mode.....:rolleyes:

Slasher
11th Apr 2002, 05:06
To reply to the threads initial question,

B737-300:

Boeing:

* At 1000 ft AGL until 50 ft radar-alt at the destination/alternate airfield (single AP).

Company:

* Any time after aircraft is established in enroute climb or cruise and all checklists are completed, until -
i) published minimum
ii) 500 ft AGL for unpublished approaches but served by a destination nav-aid suitable for center-line tracking
iii)500 ft AGL (day) and 1000 ft AGL (night) for approaches with nil electronic approach aids
iv) At the circling minima whilst manouvering at certain Company airports (due close-proximity of high terrain)

at the destination/alternate airfield.

* Notwithstanding the above, at any time the PIC deems its use necessary in the interests of safety, crew workload or expedition.

Usual on-line practice:

AP in -

1. TOPC if climb uneventful and/or a low-level crz alt

2. During enroute climb if workload high or where feelin particularly lazey!

AP out-

1. TOPD if descent/approach anticipated to be uneventful with low/medium-workload

2. Co minimum as mentioned above if where feelin a little bit bloodey fragile that day!

Ford Airlane
11th Apr 2002, 08:43
B744 - 250 feet is minimum engagement height for a/p after takeoff.

Scottie
11th Apr 2002, 09:13
737-300 A/P can be engaged at 500ft RA.

wysiwyg
11th Apr 2002, 10:23
B757 has a CAA imposed restriction of 500' aal before autopilot engagement (I seem to remember Boeings limitation is 200') for take off. The 757 does not need to have the (coupled) autopilots taken out until the very end of the landing roll in order to vacate the runway.

twistedenginestarter
11th Apr 2002, 10:35
Minds stuck in the Trident mode.....

If you haven't stuck your T* on the computer shortly after 300 feet you're a big girl's blouse. Admittedly that's just my personal opinion....

OzExpat
11th Apr 2002, 14:04
I call for zero flap at 400 feet AAL. Once it's away, I'll do me scans and engage the a/p before calling for after take-off checks. I find this spreads the workload very nicely, allowing me time to ascertain how much other traffic I need to thread me way thru.

If I'm feeling brave (only when there's little or no other traffic to contend with), I'll leave the a/p out to 10,000 feet.

For the descent, I usually take the a/p out at TOPD if the arrival is particularly awkward. But, if there's a lot of other traffic around, I'll leave it in because, no matter how awkward the arrival is, there'll be too many other aircraft blocking my descent. If I haven't disengaged it any sooner, I'll do so at the IAF or, if using a visual approach and a circuit, I'll disengage the a/p before manoeuvring to join the circuit.

A Kingair is pretty flexible tho and other circumstances can dictate the need for a different set of strategies...

G.Khan
11th Apr 2002, 14:37
L1011 - well lets see, it was a Brit. who wrote the definitive book on the auto flight system, approved by Lockheed, his name was Capt. Mike White, ex Court Line and it was the Brits who required about forty modifications to the basic B707 before it came onto the British register and Boeing adopted them all as standard,
oh, why should I go on, the list is endless!!!

On the B747-400 normally not before 400'agl. That is SOP rather than actual ability to engage.

Final 3 Greens
11th Apr 2002, 19:44
Well said Twistedenginestarter

The 121 went a bloody sight faster than the 1011 too, but what would these Yanks know.

... and they had to offset the nosewheel on the Trident because the autoland was so accurate it would hit the centreline lights and worry the pax...

... and the Tristar autoland was developed by the Smith team, who went to Lockheed...

..and one of these days I'll find one of the real thing and be able to see what it does outide the sim :D :D :D :D :D

twistedenginestarter
11th Apr 2002, 22:49
Final3

You're the right stuff!!

And don't worry about the sim thing. Some planes only live on in our (fading) memories. But they live on all the same....

I thought the Tristar was a lovely plane (not just because it started with a T) and am sad I never had a go on one.

Slasher
12th Apr 2002, 01:24
Scottie just for my own benefit where do you get that the 737-300 AP is permited be engaged at 500 ft RA? Boeing says above 400 ft RA it is capable of being engaged but is your published Boeing Limitations diferent from mine?

West Coast
12th Apr 2002, 05:59
CRJ 600ft

TheDrop
12th Apr 2002, 07:39
The only possible danger I can see of engaging the autopilot too early is if it has a malfuntion (not detected in ground testing) and pitches down or some other unpleasant maneuvre. To have some hundreds of feet height would give the pilot a chance to disconnect it again and gain control.

Lear 31A - 200' minimum on approach (CAT I aircraft), 1000' enroute. The latter must mean not to engange until 1000' AGL I suppose.

TD

rubik101
12th Apr 2002, 10:52
Slasher; Why at minimums if you can leave it engaged until 50'? Make use of the facilities!!
On occaisions of steady cross wind, low cloud and perhaps rain, poor vis etc. leaving the autopilot engaged until 50agl is a real help. All you have to do is flare and retard the power. QED

shon7
12th Apr 2002, 15:11
Thanks for answering my questions guys. Now that I know what the minimums are for engaging the AP, I am wondering what the standard operating procedure is. That is to say - in your flying when do you engage the AP. Is it after levelling off at the initial cruising altitude?

Also what does TOPD and TOPC stand for.

Thanks once again.

OzExpat
12th Apr 2002, 19:31
shon7...

TOPD = Top of Descent (ie the point at which a descent is initiated).
TOPC = Top of Climb (ie the point at which a climb is terminated).

BEagle
12th Apr 2002, 19:57
In HMFC's quaint old Vickers Funbus, after the noise and smoke of the take-off one instructs one's man to retard the thrust to noise abatement levels at 1500' agl. One then climbs to 3000' agl before accelerating to flap retraction speed. When the flaps and slats are UP and IN, one instructs one's man to set climb power and one then engages the autopilot of choice. One then consults one's directional consultant as to the health of the FMS. If all is well, one engages the lateral navigation mode and the autopilot may remain engaged until 200' agl on final approach - at which point one disengages the autopilot and autothrottles and one's man advises the % RPM set. One completes the final approach and commands one's man to select idle thrust before flaring the old lady to a featherlight touchdown..............

Slasher
12th Apr 2002, 21:00
Boeing stipulate 50 ft for single AP operations. The limitations I described are Company requirements which can differ from operator to operator. Here in the tropics bad wx is usualy heavey rain combined with strong variable crosswinds (thunderstorms) precluding the use of AP down to 50ft. Further, 50 ft is too late in getting the feel of the aircraft and the crosswind (esp in cases of engine-out and/or flight-control malfunctions). Lastly, only a few of our airports are equipped with ILSs. Most are NDBs and the odd VOR.

As I recall there are also AP-hardover issues for B737-200/300/400/500 single AP use. This could be related to undetected or late IRS faults at low heights but Im not sure.

machcruiser
13th Apr 2002, 05:58
For the B757 Boeing says one can engage auto pilot at 400' agl.

gas path
13th Apr 2002, 10:02
after the noise and smoke of the take-off one instructs one's man to retard the thrust to noise abatement levels.........

In a VC10??........... that made I larf :D :D :D :D

411A
13th Apr 2002, 16:14
Ah yes BEagle...but one has to have a (shishhh now, not to wake the younger guys), dare I say it...Flight Engineer. That fellow back there that keeps all the fluids, air, electrics...in their proper places...mostly by sheer skill....and all without the need of magic black boxes.
Simply amazing.
And never appreciated today by one's directional advisor.

Final 3 Greens
13th Apr 2002, 19:23
411A

Ummmmm - isn't your thinking on flight engineers just a little bit TRIDENT oriented - I mean the 1E, as the 1c, 2e and 3b all had 2nd officers as they moved on in their thinking a little bit ;)

411A
13th Apr 2002, 20:06
Thats the problem, Final 3 Greens.....2nd officers, completely different than PROFESSIONAL Flight Engineers...some of these guys were only warming the seat...waiting for a front view.
And yes, the Trident pioneered autoland technology....but the big three engine Lockheed does it better. And certainly better than Boeings of the past. :rolleyes:

Jetlagged
13th Apr 2002, 20:44
Hmm, a sure way to **** of your colleauges is to invent SOP's, when all else fails do what the book says

dv8
13th Apr 2002, 20:45
F100
NAV engages at 30' AGL and AP can be engaged at a minimum of 35'


mmmmm Fokker:)

Final 3 Greens
15th Apr 2002, 21:31
411A

Didn't the 2 nd officers get promoted to fly 737 and 757s and other new gen jets that were even better and didn't need FEs?

BTW - only teasing really - only ever went on the 1011 as a Pax and that was pretty good! All the best.

;)