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pizman82

Asiana 214 Crash Hold Mode

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Hello.

 

Today i try to replay the Asiana214 Crash of San Francisco in my FSX with the PMDG 777  .  I Know there are some Threads about this topic but non anwserd my question and i don´t want to refresh a years old topic.

 

 

I Used that video https://www.youtube.com/watch?v=8MFPSfGoT1U to rebuild the situation....

 

My Problem:     I Make more than 20 Trys but i NEVER becom a "Hold" Mode of the AT.

 

After more trys in other conditions i realise that the HOLD Mode only comes if i make a Descent by the FLCH.     For Example i´m on 10.000 Feet.   Make a Target Alt of 6000 in the MCP and then push FLCH.  After that i´m able to activate HOLD when i Pull the Throttle manualy to IDLE.  BUT:   If i reach the Target Altitude the throttle mode switches Automatic from HOLD to SPD.

 

If i understand the Intruductions and my tests correct then a HOLD Mode only eneamble when i make a DESCENT with FLCH.  NEVER on a Climb.

 

 

At this point i can´t understand that Video.    The Pilot push the FLCH Button while a higher Target ALT is setted.    The Plane started to climb.  He Disable the AP.  In these Situation its not possible to get into HOLD Mode i think.

 

The Only way i can Reproduce the Situation is to set Target ALT to "0"  Zero.   BUT:  In the Video the Target ALT is already 3000 till the crash.

 

 

Can you tell me please....  Did i make something wrong ??     Is the Video Wrong ???   Or is the PMDG777 not simulated that system like in the Real Plane ???

 

Thank you !

 

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Update:     After a few hours of google searches i find a interesting thing  ( Not shure if i allowed to link a other board webside here  If yes please tell me then i put in the url )

 

they wrote that in a real 777 the pilot can get into a HOLD Mode when he pull the Thrustleaver "against" the servos for maby 2 Seconds.  If this is corect i understand now the Situation,

 

Is this in the PMDG possible too ?     If i Spam the F1 Button to get the thrust in IDLE while the AT will speed up it should be the same procedure. BUT The Hold Mode not come alive.

 

 

By the Way.   I´m realy deeply shocked about the Posting from this Guy who explane it on the other Board.     It´s timed to 2008   FIVE Years bevore the crash....   He says : 

 

 

777 FLCH in climb and a/t going into HOLD, no low speed prot............  Did anybody experienced this? And if yes, would you think that it could be a safety issue.

 

What a foreboding !

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Update:     After a few hours of google searches i find a interesting thing  ( Not shure if i allowed to link a other board webside here  If yes please tell me then i put in the url )

 

they wrote that in a real 777 the pilot can get into a HOLD Mode when he pull the Thrustleaver "against" the servos for maby 2 Seconds.  If this is corect i understand now the Situation,

 

Is this in the PMDG possible too ?     If i Spam the F1 Button to get the thrust in IDLE while the AT will speed up it should be the same procedure. BUT The Hold Mode not come alive.

 

I think the only way you can reproduce these events in the PMDG 777 would be to disengage the A/T when you disengage the AP, then idle the throttles. Then switch off the Capt's flight director (which is what prevented the "wake up" A/T mode operating).

 

As you have discovered, at present the A/T simulation doesn't go to hold mode if you override the A/T in FLCH, as the aircraft does.

 

By the Way. I´m realy deeply shocked about the Posting from this Guy who explane it on the other Board. It´s timed to 2008 FIVE Years bevore the crash.... He says :

What a foreboding !

If you read to the end of that thread there is some speed protection remaining.The general view of others replying is why would you intervene like that in a climb and that the situation is not a problem if the pilot keeps on top of the situation he has intervened in.

 

This is something Boeing deliberately designed in, not a flaw in the logic.

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@ KevinH    

Thanks for that info.     The 777 is my second Product of PMDG (i already got the 737NGX) .  I´m verry impressed about the technical deep simulation.   Just wondering that this precedure is not simulated.  But no Problem.   May its a idea for the next Products to enter a smal info in the manuals what elements are NOT simulated.   that prevents users for houres of testing.

 

And about the quoted Thread.....

 

I Agree.  the System isn´t a failure.  And if the Pilot not do lots of mistakes in a row that will not happend.     I´m not a real Pilot and my perpective is from a amteur.    But i think the problem is a missing Warning.

 

In HOLD  mode there is just a illuminated Green Spot in the PFD that looks like SPD or THR.     There is no Aural warning when get into HOLD or a Yellow Warning in the EICAS for example. 

 

May it will prevent problems if there will be a Acustic Warning like "No Throttle - No Trhottle" when you are in Hold mode and Speed is more than 20kn under the Speedbug for example. 

 

But final....   In Millions of Miles flown by the Trippel7 theres only one time happend.   Thats a argument too.

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@ KevinH

Thanks for that info. The 777 is my second Product of PMDG (i already got the 737NGX) . I´m verry impressed about the technical deep simulation. Just wondering that this precedure is not simulated. But no Problem. May its a idea for the next Products to enter a smal info in the manuals what elements are NOT simulated. that prevents users for houres of testing.

 

And about the quoted Thread.....

 

I Agree. the System isn´t a failure. And if the Pilot not do lots of mistakes in a row that will not happend. I´m not a real Pilot and my perpective is from a amteur. But i think the problem is a missing Warning.

 

In HOLD mode there is just a illuminated Green Spot in the PFD that looks like SPD or THR. There is no Aural warning when get into HOLD or a Yellow Warning in the EICAS for example.

 

May it will prevent problems if there will be a Acustic Warning like "No Throttle - No Trhottle" when you are in Hold mode and Speed is more than 20kn under the Speedbug for example.

 

But final.... In Millions of Miles flown by the Trippel7 theres only one time happend. Thats a argument too.

A/T HOLD mode does not require a caution. It's normal operation not abnormal. The word HOLD is very clear in real life not a green blob. Also every FMA change is boxed for 10 seconds and the flight crew are supposed to read out every new annunciation so the implications are recognised. None of the Asiana crew noticed and called out the FMA change to HOLD.

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Compare the NTSB abstract regarding the "FLCH trap" and associated NTSB recommendations:

 

http://www.ntsb.gov/news/events/Pages/2014_Asiana_BMG-Abstract.aspx

Yes, but there is no recommendation for Boeing to change the 777 AFCS system design or operation. Just to update manuals and develop training to demonstrate when A/T speed protection is provided and when it isn't. This A/T design "feature" was noticed during 787 certification and was changed on that aircraft. The FAA and EASA did not require the change to be made retrospectively to the 777.

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