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vpiragibe

No TRK or Heading Hold on Take Off , airborne below 400 feet

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G550flyer.

 

Thank you for your reply.

 

We are talking about the same thing. Here we call it EOP ( eng out procedure )

 

Some of those EOP, requires to maintain the runway track or make a turn a a specific point. When heavy, if an engine failure occurs, it is necessary to abandon the SID and perform a turn below 400 AGL.

 

Here comes the TRACK SEL below the 400 feet.  It is possible and should be used in this event.

 

It is not correctly modeled in the PMDG 777 . This feature is inhibited .

 

The original post was to check if someone's else was having the same problem, as I am still struggling with the stability of my 777.

 

Hope you understood me know.

 

Regards

 

Vpira

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G550flyer.

 

Thank you for your reply.

 

We are talking about the same thing. Here we call it EOP ( eng out procedure )

 

Some of those EOP, requires to maintain the runway track or make a turn a a specific point. When heavy, if an engine failure occurs, it is necessary to abandon the SID and perform a turn below 400 AGL.

 

Here comes the TRACK SEL below the 400 feet.  It is possible and should be used in this event.

 

It is not correctly modeled in the PMDG 777 . This feature is inhibited .

 

The original post was to check if someone's else was having the same problem, as I am still struggling with the stability of my 777.

 

Hope you understood me know.

 

Regards

 

Vpira

The manual does state that the LNAV will become active at 50 agl, you are correct. The question I have is what will the FMC depict. I'll research and see if the FMC will keep you straight until a certain altitude before commencing the turn.

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zzr7.jpg

This is from the FAA departure procedure program. So in the U.S., the SID would take you at least to 400ft DER before the turn. So for FAA airports, by design the FMC would reach 400ft DER before the turn when flying the database SID.

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Depending on the SID, and some have a initial 'conditional' turn ( like : 400 feet or X distance from a VOR ) whichever is earlier, if you keep in LNAV, the plane will turn, following the FMC LEGs page.

 

The point is: I dont want to follow  the SID anymore and LNAV is already engaged ( 50 feet ).  I want to either turn to maintain a desired ( EOP ) XXX track or even maintain the runway Heading or Track.

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zzr7.jpg

This is from the FAA departure procedure program. So in the U.S., the SID would take you at least to 400ft DER before the turn. So for FAA airports, by design the FMC would reach 400ft DER before the turn when flying the database SID.

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G550flyer.

 

I do agree about the FAA SID 400 feet requirement. This is for a normal Departure.

 

I am talking about Emergency procedures, when the aircraft cannot follow the SID and have to follow a different path.  Every company publishes it's own EOP.

 

These EOP , sometimes, do require a turn, even before 400 feet AGL. Hence the need for TRK SEL below 400.

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I beg to disagree, gentlemen.

 

Let me give you an example: 

A normal departure TO mode ( THR REF / TOGA / TOGA ) with LNAV and VNAV armed. This is the standard set for all airlines. Max use of automation.

You are very heavy, and the SID today ( that requires a steep climb gradient ) calls for a 90* turn at half a mile after the opposite runway threshold . All set in LEGs page.

During the TO roll, at VR, BANG! you have an engine failure.

At 50' the Roll mode engages automatically to LNAV. ( another example of roll mode changing below 400 feet )

Luckily, the terrain ahead of the runway is flat as a pancake.

At the 1/2 mile position, the LNAV will call you to turn, but the plane is still below 400 feet ( you are heavy, remember? ) , and you want to continue straight ahead and not follow the SID anymore.

You have 2 options :

1 ) before the 1/2 mile position, select TOGA again, get rid of LNAV and VNAV ,holding the track you have when pushing the TOGA button ( roughly runway track, what is good as you want to continue straight ahead. ) However, you gonna miss the VNAV mode at 400 feet. No big deal, as you can reselect VNAV at or above 400 feet and have the aircraft accelerating to the speed bug at the engine auto acceleration height ( Take off REF page 2/2 ) futher retracting your flaps and so on...

2 ) before the 1/2 mile position and still below 400 feet, select TRACK SEL. This way you get THR REF / TRK SEL / TOGA ( with VNAV armed ) until 400 feet. As the track selector is normally set to the runway alignment, you going to have the desired track when airborne, not a turn on LNAV, plus the benefits of VNAV at 400 feet.

 

Mr. hopskip, for your info this is not my desire. This is how it works in the RW.  Real Boeing 777.

 

Mr. 3-2-1 now, auto pilot engagement is necessary as soon as the aircraft is in trim and above 200 feet AGL. If you have an engine fire, you need to confirm every movement of your partner ( Pilot not flying ) during the execution of the memory items. If you wait until the plane is above 1000 feet to start your actions you are doomed !  Heavy birds are far different from a Cessna.  Autopilot is your friend ( when you know how to use it ) not your enemy...

 

PMDG, please, review this feature in your next update.

 

Vpira

 

Vpria,

 

Maybe these things are the case at your airline in your country, but they certainly are *not* universal. "Max use of automation" is certainly not the rule in here in the US. *Smart* use of it is. Knowing when to use the "dumb" modes vs/ trying to program everything into the FMC, knowing when to take over by hand etc. Numerous airlines in the US encourage hand flying up to 10,000 feet or so, conducting hand flown visual approaches etc to maintain proficiency with the actual act of piloting, something that appears to be on the decline in highly automated aircraft.

 

In your scenario there is a very obvious third option - put your hands on the yoke and make the airplane do what you need it to. This kind of "blinders on" reliance on the autopilot has gotten people killed before and likely will again unfortunately. We've seen 3 major accidents in the past year that had automation dependency as a huge factor.

 

I will ask our tech advisors about the mode changes below 400 feet thing, but I find it hard to believe something like that was missed. LNAV engaging at 50 feet is a different thing and is specifically related to having armed it prior to takeoff - this isn't a normal mode change that the AFDS would allow if you hadn't armed it prior to takeoff.


Ryan Maziarz
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Also - the real 777 will automatically load the engine out SID into the FMC in cases where the normal SID is not appropriate for single engine ops. This takes care of your scenario. (This isn't modeled in our 777 currently due to navdata limitations - we'll probably do it when we design our new navdata format)


Ryan Maziarz
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Not really.

777 doesn't load any engine out procedure.

You can build it (as a technique) in the fix pages, but it would be there for you as a reference, to be followed by HDG/TRK Sel or manually, but not to be followed by LNAV.

Again, as a technique, you might set it on Route 2 and activate it yourself, but I would strongly NOT recommend touching anything untill a safe altitude has been reached.

Vpria is correct, and to answer his question you must follow your procedure manually up to 400ft, where a roll mode can be armed ( if you need to turn. If you don't, just engage the AP at 200ft and concentrate on flying the plane).

As Vpria said, 777 is not a Cessna, and in case of an engine failure, or ANY failure in ANY phase of flight, not using automation would just be silly airmanship.

I let the cowboys do that, but usually the results are disastrous.

Managing the failures, especially when you're so closed to the ground, is far more important than proving you're a TopGun manually flying an extremely complex machine.

Hand flying means loosing a pilot, who will be concentrated in aviating and navigating, instead of managing what is going on, and what to do next.

 

Some Airlines will train their pilots hand flying (no automation AT ALL on all sorts of normal/non-normal manouvres you can think of) with 2 extra simulators every year. I find this procedure much more effective than flying an SID or climbing to 10000ft (WOW!! 10000!!!) applying max 25deg of bank.

Do you relly need that???

 

Vpria explained precisely how the mode works below 400ft, so I have nothing to add on that.


<p>Francesco

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Not really.
777 doesn't load any engine out procedure.
You can build it (as a technique) in the fix pages, but it would be there for you as a reference, to be followed by HDG/TRK Sel or manually, but not to be followed by LNAV.
Again, as a technique, you might set it on Route 2 and activate it yourself, but I would strongly NOT recommend touching anything untill a safe altitude has been reached.

 

Actually this is a airline specific option with approved engine out SID.

 

7m26.jpg

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Mr Ryan PMDG and fellow forum users

 

1) The LNAV engagement at 50' is not related to an armed option mode prior to Take Off.  You can even try in your own product and it will beautifully engage LNAV below 400"

 

2) Another proof of modification below 400 feet happens when you press TOGA , when airborne below the 400'.

This way you get rid of the LNAV and VNAV, however you have the TRACK / Heading inhibited until you reach 400, and other events will happen, but not in discussion now.

 

3) As Mr Lekijiji stated, the auto EO procedure is not modeled and I dont think many airlines use it nowadays. Anyway, this is not the theme of this thread.

 

4) Could you please check with your technical advisors if it is true or not the TRACK-HEADING SELect availability below 400 feet and give us an answer ASAP?

 

I do believe PMDG is a wonderfull product, which I was waiting for some years to realize. Thank you PMDG people !!

 

Being mainly focused to the GA and Sim enthusiasts, it is also a tool for the RW pilots that would like to use it as an instrument for self training ( considering its limits and diferences, of course ) . I am just trying to add my coment and make it better, Mr Ryan. Your aggresive and non sense coments to my post were already politelly forgotten.

 

However, I do think PMDG should also hear to your costumers and consider a 2D panel in the future.  For those enjoying the VC, congratulations !  My needs and other costumers may be diferent from yours, so please, refrain from answering on behalf of PMDG when so many people ask info about 2d panels.

 

Regards to all

 

Vpira

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Just to clarify, because I also messed up, Vpira is absolutely correct.

The only time roll modes are inhibited below 400' is when you select TOGA above 80kts and below 400 feet.

My mistake.

 

G550, I had a look on the official B777 Honywell FMC manual, but couldn't find souch a capability.

Where did you find that extract?

Always interesting to know


<p>Francesco

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Quoting a FAQs from a known airline,and the up-to-date FCTM reference :

 

 

Subject :Engaging roll modes below 400’ on Engine Out Procedures
May I engage a roll mode below 400’ during an EOP?
Answer: YES
B777 Frequently Asked Questions Page XX

Manual 01 July 2013
Background on Roll Modes below 400’
The current phase has highlighted a misunderstanding with regards to engaging roll modes below 400’ during Engine out Procedures. Examples include LIMC RWY 35 where the SID requires an immediate turn, whilst the EOP is straight ahead and; Dubai RWY 30R where in a heavy aircraft we may need to commence the EOP left turn prior to reaching 400’.
In a technical notice from Boeing they clarify the procedure described in FCTM pg 3.33 as follows “If the crew wants to fly straight ahead following an engine failure on takeoff without an engine out SID available they should select HDG SEL or TRK SEL below 400' AGL if necessary due to the emergency situation”.
This complies with the statement in the FCTM “If ground track is not consistent with the desired flight path, use HDG SEL/TRK SEL/LNAV to achieve the desired track”. Ultimately the EOP safety cone and terrain clearance is the priority and pilots should make every attempt to regain the centreline of the prescribed EOP track until above a safe altitude.
For these reasons crews need to take a practical approach and brief each take off with consideration for the various implications and options available. Examples include pressing the TOGA switches below 400’ which could either assist or constrain as below:
- disarm LNAV/VNAV modes and hence would prevent the LNAV engagement and subsequent turn onto the SID in the case of LIMC and as such assist the straight ahead EOP.
Conversely
- inhibit the ability to engage HDG/TRK below 400’ if the Engine failure occurred after the turn had commenced, or in the case of Dubai inhibit the ability to make the turn until 400’ unless reverting to manual flight, (In this case pushing the thrust levers forward rather than pressing TOGA may be more suitable).

 

777 Flight Crew Training Manual
Takeoff and Initial Climb
Boeing Proprietary. Copyright © Boeing. May be subject to export restrictions under EAR. See title page for details.
3.34 FCT 777
Initial Climb - One Engine Inoperative
Initial Climb - One Engine Inoperative
The initial climb attitude should be adjusted to maintain a minimum of V2 and a
positive climb. After liftoff the flight director provides proper pitch guidance.
Crosscheck indicated airspeed, vertical speed and other flight instruments. The
flight director commands a minimum of V2, or the existing speed up to a
maximum of V2 + 15 knots.
If the flight director is not used, attitude and indicated airspeed become the
primary pitch references.
Retract the landing gear after a positive rate of climb is indicated on the altimeter.
The initial climb attitude should be adjusted to maintain a minimum of V2. If an
engine fails at an airspeed between V2 and V2 + 15 knots, climb at the airspeed at
which the failure occurred. If engine failure occurs above V2 + 15 knots, increase
pitch to reduce airspeed to V2 + 15 knots and maintain V2 + 15 knots until
reaching acceleration height. Select ENG OUT climb after flap retraction and all
obstructions are cleared.
The flight director roll mode commands ground track after liftoff until LNAV
engagement or another roll mode is selected. If ground track is not consistent with
desired flight path, use HDG SEL/TRK SEL/LNAV to achieve the desired track.

 

June 30, 2013     FCT 777         page  3.34

 

Vpira

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