Using Reverse Clears V Speeds

[John H Watson]

An interesting message thread on PPRuNe

http://www.pprune.org/tech-log/594748-reverse-during-taxi.html

[Hardy Heinlin]

Maybe this will remind the crew to recalculate the V speeds after a (high speed) RTO?

[Britjet]

Selecting reverse has always cleared the V speeds. I thought PSX did that?
Peter.

[Hardy Heinlin]

The current PSX version doesn't do that.

I mean, on a normal flight the V speeds are already deleted during the departure; so when you land they are already blank anyway.

Is there anything else that the reversers delete in the FMC?


|-|ardy

[Britjet]

I don't think so..
Peter

[Hardy Heinlin]

The V speeds are also deleted on initial flap retraction after takeoff (this is modeled in PSX).

Could it be that the "deletion-by-reverser" effect is related to the flap control system? As we know, some LE flaps are retracted during reverser operation (this is modeled in PSX).


Cheers,

|-|ardy

[Hardy Heinlin]

The modification is now available in PSX version 10.1.4:

http://aerowinx.com/board/index.php?topic=4191.0


Regards,

|-|ardy

[Britjet]

The V speeds are also deleted on initial flap retraction after takeoff (this is modeled in PSX).

Actually - the V1/Vr speed disappears from the speed tape as soon as the aircraft gets airborne. I'm not sure if this is the same thing as clearing from the FMC though.
The youtube video of our sim session that I sent you, Hardy, shows it at 4:19
It may not be the same thing..

Peter

[Hardy Heinlin]

Now we're talking about two places: PFD and CDU.

In PSX too V1 and Vr are removed from the PFD after lift-off. But not from the CDU.

Some airlines have a V2 marker on the PFD.

V2 is removed from the PFD after initial flap retraction. But not from the CDU.

The three V speeds on the CDU blank later.

I was referring to the FMC message "TAKEOFF SPEEDS DELETED". This message won't occur in flight.


Cheers,

|-|ardy


Please disregard this quote:

The V speeds are also deleted on initial flap retraction after takeoff (this is modeled in PSX).

I meant to say: The V speeds (on the CDU) are also deleted 2 minutes after lift-off (this is modeled in PSX).

[Britjet]

Indeed. I just checked it tonight. V speeds disappear from CDU at 2 mins.
Peter