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-   -   FMC Route Dump At End Of Flight? (https://www.pprune.org/tech-log/140648-fmc-route-dump-end-flight.html)

NSEU 10th August 2004 01:52

FMC Route Dump At End Of Flight?
 
I understand there are variations when it comes to what happens to FMC Route data at the end of a flight.

I've been told by a pilot that a 737 will dump Route info at 20kts during rollout (Smiths FMC)... I've also been told that a 744 FMC (Honeywell) holds Route 1 missed approach data and all of Route 2.

As a maintenance engineer on 744's and 767's, I do recall seeing some Route data remaining on the ND's/EHSI's after a flight, but, at the time, wasn't able to determine what Route (1 or 2) the pilots had actually used during approach/landing.

Does anyone have any other opinions/data on this. In particular, I'd like to know what happens on a 767 Honeywell box. If the data is dumped, is it based on air/ground, flaps, groundspeed or something else... or a combination of these.

BTW, I understand the initialization data is dumped from a Honeywell box when the fuel cutoff levers are set to cutoff.

Thanks in advance.
Regards.
NSEU

McGreaser 10th August 2004 19:50

According to the BOM Vol 2 that l have "thirty seconds after engine shutdown, the flight complete phase clears the active flight plan and load data". From my little experience this entails the whole of route 1 and just leaves route 2 still on the fmc. Hope that helps....:ok: Lest l forget this is for the B767:O

NSEU 11th August 2004 02:27

Thanks for the feedback, McGreaser. Other sources have reported that the 30 second after engine shutdown logic is correct for the 767. However, I have been made aware that there may be options in this area. Looking into this now.

Best regards.
NSEU.


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