markjans

FMS PROF speed on final approach

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Hi,

Does anyone know what, during the approach, the trigger for the FMS PROF speed is to get down from 250 knots to lower?

In Airbus models, arming the "approach phase" causes the speed to be set to VAPP. The 717 does not have such a function and I'm not sure what event is supposed to trigger the autoflight speed to go from 250 to VAPP. Obviously I could manually intervene the speed but that's not essentially my question.

Also I'm curious if real world pilots would typically leave the speed set to FMS PROF SPEED all the way down to touchdown, as long as traffic is quiet and ATC restrictions are no factor.

Thanks for any replies!

Mark Jansen

 

Edited by markjans

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Should the FMS speed ever get into the amber band on approach (e.g. automatically computed and flown that slow)?  That seems to happen routinely for me with slats/flaps extended, on final, and FMS speed selected...wind up just pulling the speed knob and manually dialing in Vapp (Vref+5 or whatever other wind speed correction).

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On 7/28/2018 at 5:14 AM, markjans said:

Also I'm curious if real world pilots would typically leave the speed set to FMS PROF SPEED all the way down to touchdown, as long as traffic is quiet and ATC restrictions are no factor

SOP at my company is to select PROF speed with landing flap selection, then preselect missed approach speed and altitude.

 

On 8/3/2018 at 12:47 AM, CaptKornDog said:

Should the FMS speed ever get into the amber band on approach (e.g. automatically computed and flown that slow)?  That seems to happen routinely for me with slats/flaps extended, on final, and FMS speed selected...wind up just pulling the speed knob and manually dialing in Vapp (Vref+5 or whatever other wind speed correction).

It should not. I'm sure you've done this, but make sure you landing flap and landing weight are set properly.

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On 8/6/2018 at 12:41 PM, spickle said:

 

 

It should not. I'm sure you've done this, but make sure you landing flap and landing weight are set properly.

They are.

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SOP at my company is to select PROF speed with landing flap selection, then preselect missed approach speed and altitude.

Does that mean that NORMALLY, even when ATC speed control is no factor, SOP is to perform the initial approach phase with manual speed control while only re-selecting PROF speed upon landing flap selection? I'm just curious what the most realistic way is to operate the airplane in this matter.

Thanks!

Mark

 

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On 8/10/2018 at 3:57 AM, markjans said:

Does that mean that NORMALLY, even when ATC speed control is no factor, SOP is to perform the initial approach phase with manual speed control while only re-selecting PROF speed upon landing flap selection? I'm just curious what the most realistic way is to operate the airplane in this matter.

Thanks!

Mark

 

Yep, that's exactly right. 

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I've noticed that it doesnt slow down to the exact approach speed in the FMS. Your Vapp can be 141 but it only goes down to 145 (no wind correction needed).

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On 7/9/2019 at 7:25 AM, bravomike said:

I've noticed that it doesnt slow down to the exact approach speed in the FMS. Your Vapp can be 141 but it only goes down to 145 (no wind correction needed).

I'm seeing the same, always just have to pull the speed knob.

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This should be fairly easy to code. Simply if gear down and flaps 40, and RA below 2000', use FMS Vapp.

Edited by bravomike

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