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B737 Takeoff with VNAV and LNAV disarmed

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B737 Takeoff with VNAV and LNAV disarmed

Old 11th Sep 2019, 08:06
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B737 Takeoff with VNAV and LNAV disarmed

Hellow everyone, I am currently undergoing B737 and I got question to ask.

Let us say you were instructed to takeoff and fly runway heading soon after departure,
when you hit TOGA, does HDG SEL automatically selected and shows up on FMA or is it after departure ?

James


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Old 11th Sep 2019, 09:01
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yes. At least on the NG.
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Old 11th Sep 2019, 09:12
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It depends on the aircraft, as this is customer option.

It is either HDG SEL for takeoff, which means that as soon as you hit TOGA, you will get HDG SEL on the FMA, or it is wings level in which case the roll FMA will be blank.
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Old 11th Sep 2019, 11:36
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Customer options. Ours engage HDG SEL, but there is an airframe or two in the fleet that don't.
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Old 11th Sep 2019, 11:42
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As a very old fossil, why don't you just fly the aeroplane?
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Old 11th Sep 2019, 11:59
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Originally Posted by Bergerie1 View Post
As a very old fossil, why don't you just fly the aeroplane?
One can do that and at the same time want to understand how the automation behaves i.e. what to expect from it.
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Old 11th Sep 2019, 12:07
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If one is doing a course on the 737, why not ask your instructor?
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Old 12th Sep 2019, 04:59
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Originally Posted by Small cog View Post
If one is doing a course on the 737, why not ask your instructor?
1. Why have this forum if not to ask questions?
2. There are also instructors here.
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Old 12th Sep 2019, 07:27
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I would imagine that the OP will be training for a particular model/variant of the B737 and probably taking an examination too. Why confuse the matter?
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Old 15th Sep 2019, 06:22
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As mentioned it depends. Certainly on the classics and on some NGs the HDG SEL will become active on the FMA at 400’

Until then the roll mode will be blank and FD bars will command wings level
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Old 21st Sep 2019, 18:04
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Originally Posted by Bergerie1 View Post
As a very old fossil, why don't you just fly the aeroplane?
Take it easy hero. It has nothing to do with flying the plane. The guy is asking a question about how the automation works on takeoff.
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Old 24th Sep 2019, 13:16
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Originally Posted by Bergerie1 View Post
As a very old fossil, why don't you just fly the aeroplane?
I have a lot of respect for a pilot who is capable of “just flying the aeroplane” when required.

But I have no respect for a pilot who chooses to “just fly the aeroplane” because he actually doesn’t know or understand his aeroplane.

Chuck Yeager apparently would never fly an aircraft until he knew the flight manual by heart and could find every switch blindfolded.

We’d all be wise to fully understand our aircraft systems before we get airborne and be forced to exercise our superior handling skills in an attempt to cover for our lack of study and knowledge.
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Old 24th Sep 2019, 23:26
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At my company all aircraft will stay in TOGA until a lateral/vertical mode is selected. For vector departures we set the heading and call for Heading Select at 400AGL or the charted turn altitude if higher.
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Old 25th Sep 2019, 03:44
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Wait.... what?? You can actually takeoff with the LNAV and VNAV disarmed?!

Next thing you'll be telling me is that we can fly this thing without Flight Directors!

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Old 25th Sep 2019, 13:37
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Flight Director addiction, like tobacco addiction, is a real health hazard.

I say that, having operated with one simulator instructor who screams at his students to "follow the bloody flight director" even though the aircraft is in a gross unusual attitude 30 degrees nose down in a spiral dive.
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Old 26th Sep 2019, 10:12
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Originally Posted by Bergerie1 View Post
As a very old fossil, why don't you just fly the aeroplane?
Bingo! What do I win?
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Old 26th Sep 2019, 15:01
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Originally Posted by Bergerie1 View Post
As a very old fossil, why don't you just fly the aeroplane?
Old fossils are overrepresented in stall or spin during departure/landings

I've read e few reports where they don't use the ASI, but go by their "instincts" getting older.
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Old 26th Sep 2019, 16:37
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Originally Posted by ImbracableCrunk View Post


1. Why have this forum if not to ask questions?
2. There are also instructors here.
The instructors at his company will know what options their fleet has. As others have stated "it depends upon which options your company has for their aircraft."
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Old 26th Sep 2019, 17:35
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Originally Posted by Derfred View Post


I have a lot of respect for a pilot who is capable of “just flying the aeroplane” when required.

But I have no respect for a pilot who chooses to “just fly the aeroplane” because he actually doesn’t know or understand his aeroplane.

Chuck Yeager apparently would never fly an aircraft until he knew the flight manual by heart and could find every switch blindfolded.

We’d all be wise to fully understand our aircraft systems before we get airborne and be forced to exercise our superior handling skills in an attempt to cover for our lack of study and knowledge.
He'd never get airborne in a modern airliner. The manuals are much longer than the manuals of earlier eras. The P-51 flight manual was 78 pages. Switches? In a modern airliner? He can't reach about 1/4 of them.
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Old 27th Sep 2019, 13:24
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Originally Posted by jmmoric View Post
Old fossils are overrepresented in stall or spin during departure/landings

I've read e few reports where they don't use the ASI, but go by their "instincts" getting older.
Speaking as an old fossil, relying on the airspeed indicator without reference to the attitude and power settings is simply asking for trouble. I can think of quite a few accidents that resulted from chasing airspeed as opposed to setting appropriate pitch and power.

In my "old school" instrument training parlance, attitude and power are "control" instruments. Airspeed, altitude, heading, etc are "performance" instrument. You set the "control" instruments to the desired positions and then cross-check the "performance" instruments to see if you are getting the desired response. If something is out of whack, then you would first cross-check your attitude and power indicators and, if deemed reliable, continue to fly them and then determine if something is wrong with one of your performance indicators. This is a lesson that is easily forgotten in the age of modern airliners. Sadly, there are many pilots who don't get much beyond following the flight director commands, a method that probably works 98% of the time. It's that other 2% that will get you in trouble.......
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