When should autopilot be able to be engaged.

[itslovemuscle]

Only had DF 737-400 a week or so and still getiing use to the operations and fmc.
But what i want to know is i have downloaded the small tuturial from the there web site and pogrammed the fmc following the instructions in tutorial.(EHAM-EGLL).By the sounds of it you should be able to engage the AP before actually taking off,this doesnt seem to work with me,all else is ok..i take off and select v-nav and l-nav and the plane just crashes...all part of learning i suppose,but should i be able to set the AP before take off.

Cheers Gaz.

[ROI747]

you should check your climb settings and yes you need to set the AP before you take off

[LTEtabs]

400 feet radio altimeter is when you engage it. (along with VNAV and LNAV)

[itslovemuscle]

ok..it does engadge at 400 ft but not before,it sounds like you should set it when on the ground by the sounds of the tutorial,but even then the plane doesnt seem to respond properly,also the v nav seems to have a problem coming on sometimes aswell.

cheer..gaz

[AndyX]

I have the same problem to... And this is bad :(

[itslovemuscle]

ok.just done a flight from egcc-egll.i have found that if you laod a flight from the fmc that you saved earlier then it dosent seem to work properly and hence the probs getting v-nav to come on..BUT this flight worked for me i think because i actually freshley programmed the flight into the fmc while at the gate of egcc airport...this seeemed to of worked ok,still alot to understand but at least i arrived at 37l egll...lol..keep the post coming and lets see what the best way of sorting this out is..

cheers gaz.

[xhercdriver]

LAST EDITED ON Jan-05-02 AT 11:47AM (EDT)[p]
I wonder if folks aren't having "failure to communicate" here? Are we talking about "setting up" the autopilot, or "engaging" the autopilot?

I've been flying 20 years, (not the 737 tho) and I've NEVER "engaged" the autopilot (i.e. connected it to the flight controls) on the ground. If you think about it, it seems...well...stupid. When the autopilot is engaged, it is fully capable of doing things you absolutely don't want it to do (Airbus crash, anyone?), especially close to the ground. Even 400 AGL on departure is pretty questionable judgment IMO. Having it "engaged" on the ground (if that's even possible) and then having it "take control" of the plane at some automatic altitude doesn't pass my "sanity check." "George" gets the plane when I want him to, not when he wants it.

That said, the FMC and MCP should be "set" while on the ground. The altitude, course, speed, (and possibly heading) you want to fly should all be preset, so all you have to do is engage the autopilot and press a mode selector, rather than having the autothrottles chase a "wrong" speed or have the plane banking to some incorrect heading when you wanted it to fly the VOR or LNAV.

I'm sure some airlines are more "automation-oriented" than the Air Force, but we generally always hand-flew departures using the Flight Director and then engaged autopilot on the climb somewhere. It's also usually unrealistic to expect to fly a departure "as published" complete with all altitude restrictions, as opposed to an arrival where you might well fly it exactly "by the book," so it seems to me that the VNAV function wouldn't get that much use on departure. There's just too many times where you get intermediate level-offs or track shortening to just click on VNAV, put your feet up and read your Play...er...Flying Magazine.

Just one "old geezer's" opinion. Probably others who'll say the exact opposite ;-)

[itslovemuscle]

Here is the Extract from the tutorial i was on about,note the line that says set the AP to (A) and this is before you take off...

On the MCP select the F/D to on and the A/T to arm. An FD notice will show on the
FMA (Flight Mode Annunciator) on the EADI and a green light will illuminate next to
the A/T switch.
Set the IAS/MACH to 250kts.
Set the heading to 186. This is the heading for the runway. It is good practice to set
the MCP heading to follow the FMC route. This is not necessary for correct operation
of the FMC, but just good practice in case the FMC goes AWOL and we want to use
Hdg Sel mode.
Set the altitude to 6000ft. This is the restricted altitude until we reach waypoint Valko.
By setting this altitude, it will prevent the FMC from climbing any higher until we dial
in a higher altitude, which will then allow it to climb again.
Select Autopilot A.
Our MCP is now correctly set up. Please note that we have not bothered with the
course button.

Cheers Gaz.

[ilh]

Simply put, the tutorial is not up-to-date with the patch. It is no longer possible to engage CMD A or B until 400' AGL. It is also not possible to select LNAV, VNAV, etc., until 400' AGL, even with CMD off.

Elmar, perhaps you could update your excellent tutorial? This seems to be a snag that continues to catch people. Also, I think one of the waypoints in STAR changed names during one of the AIRAC updates.

Lee Hetherington (KBOS)

[Martin]

You're absolutely right. To summarise it:

The autopilot and FMC should be set, and the F/D should be engaged on the ground. Depending on aircraft/pilot discretion different autopilot modes can also be selected on the ground (e.g. selecting VNAV and LNAV on a 767 for an F/D takeoff). After takeoff, usually not before the flap retraction altitude, the autopilot can be engaged.

Hopefully that was yet another fairly clear explanation of the procedure... :-)

Martin

It's a lot like life and that's what's appealing (flight sim, that is)

[ToddNicholson]

This is also clearly spelled out in the documentation included with the final update:) A/P can be engaged only above 400ft AGL.

Todd

[JPRavain]

ask your lovemuscle stud.

:-lol
JP

[Martin]

Yes, it can be engaged as low as 400' AGL, but can you find an airline that actually does that? Usually it's not engaged until at least 1000' AGL. Also, I was trying to explain the terms set, select and engage, since they are often mixed up.

Martin

It's a lot like life and that's what's appealing (flight sim, that is)

[itslovemuscle]

cheers all for the replies and now it makes more sense..lol..
Cya Gaz.

[AndyX]

OK!!!

May be some one tell me (and other FS Pilot) the right instruction from take off to appr.

[harrneil]

Go to www.utem.com

Mike Ray has written an excellent book which will help you all.

Neil.

[whoosh]

Hi Lee,

So it seems :-) Indeed, with the latest update, the autopilot can no longer be set on the ground and with the latest AIRAC cycle, the STAR used in the tutorial had a namechange.

Best regards, Elmar

http://www.dreamfleet2000.com/gfx/images/Forum_Banners/DF_BANNER_FORUM_ELMAR.jpg