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Flap at FAF


If you fly a pre-J Mooney, how much flap do you put in at the FAF to stabilize your glide?  

31 members have voted

  1. 1. If you fly a pre-J Mooney, how much flap do you put in at the FAF to stabilize your glide?

    • None
      15
    • 1 pump (~7.5 deg.)
      1
    • 2 pumps (~15 deg.)
      13
    • 3 pumps (~23 deg.)
      0
    • Full flaps
      2


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How much flap do  you put in at the FAF to stabilize your glide?  Thanks.  I'm curious to learn what most folks do.


I think you are going to find various answers based on the plane involved.

For my plane with a VFo/VFe of 109 KIAS and VLo/VLe of 104 KIAS, I find that extending the flaps to 15° and setting power at 16”/2400 before I reach the FAF stabilizes the plane for level flight at 100 KIAS. Dropping the gear at the FAF with a small power adjustment keeps me at the 100 KIAS while descending at 500 FPM.

When I break out, I will decide whether to land at 15° or if needed, go to the full flap setting of 33°.


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@Fred_2O, note that @Marauder flies an F model . . . I use the same procedure in my electric gear C, except I generally fly towards the IAF at 23"/2300, turning on course and slowing to 105-110 mph with Takeoff Flaps. At the FAF, I drop gear to descend; or when the glideslope comes alive and the needle falls to 1-1/2 dots high.

Flap speed = 125 mph

Gear speed = 120 mph

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Fred,

An important point to cover when discussing pumps and flap angles...

The first pump pressurized the system...no movement...

2, 3, and 4 moves the flaps 1/3 of the total travel... each.

Then there is 4.3 the last amount that isn’t a full pump.

That will adjust how people are answering your question...

Best regards,

-a-

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In the '67 C the top of the white arc is only 87 kts.   Sometimes while trying to keep it on glideslope, I've started to go out of the white arc, which is bad.   I think that what I'm going to need to adopt to eliminate that problem is to do as @Andy95W and @Browncbr1 do, and just not put in any flaps until I break out.  With any flaps down the speed envelope for staying on glide slope is only 12 kts if one doesn't want to go any slower than 75 kts.  For me with my current skill set, that's just too narrow.   So, the difference in white arc limits associate with different models/years of the M20 family make my poll rather meaningless.   I should have asked this question only of those of you with pre-68 M20C's.

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With my '62C, I approach glide slope 18" and 2300, adjusting power to insure I'm at gear speed 120 mph. At intercept I drop the gear and reduce MP to 15". I can the adjust MP to stay on the glide slope and work the prop to max setting for the missed approach or landing. Work the flaps in once you break out for landing. 

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My personal mindset, for pre-1968 Mooneys on Instrument approaches is that flap use depends on the altitude you break out.

On an ILS to real 200' minimums, I will land with no flaps.  The minimum length for an ILS runway is 5,000- no flap landing should be a no-brainer and 200' AGL is no place to be dicking around with configuration changes- IMHO.

On a non-precision approach to a shorter runway, I would add flaps until about 300-400 AGL.  My personal minimums for a circling approach is 800 AGL, so I'll treat that as a fairly normal traffic pattern, with the exception of gear down FAF inbound.

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Even on the 68 and later Cs,  Flap speed only goes up to 125mph, just 5mph faster than gear speed. If I’m going to slow down to that speed range just outside the FAF,  I feel like I might as well get GUMPS over with and focus on the final segment without worry of forgetting the gear. Dropping the gear alone at that speed gives me the right performance to come down the glideslope at ~90kt and ~16 MAP with no flaps. I have no need to go any slower than that, and adding flaps would make me add power. The flaps get dumped in all at once on 1-2mi final after breaking out of the clouds.

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40 minutes ago, Andy95W said:

This thread may take an ugly turn if we start talking about whether to use flaps on takeoff or not.

There's no debate. My Owner's Manual says "FLAPS--Takeoff or as desired." So I do what I want every time.   B)

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13 hours ago, McMooney said:

74E  flaps at takeoff ( only position marked ), 2300/16in

Does your engine/prop not have the "No continuous operation between xxxx and 2350" requirement?  xxxx becuase I don't remember the lower limit. 

Does anyone know the reason behind this requirement?  Obviously I wouldn't setup in cruise at 2300 for a long xc, but does a low power decent at 2300 for 5 minutes in an approach pose any risk?

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Shot 2 ILS approaches at KBHM today, and one RNAV at 3M8.   Slowed to 105 kt and gear down at FAF, set power to establish 80-85 kt glide with no flaps.  Deployed flaps as  needed after DH or MDA.  Worked great.  I think this is a workable strategy for me.  Thanks everyone for providing your input.

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8 hours ago, bob865 said:

Does your engine/prop not have the "No continuous operation between xxxx and 2350" requirement?  xxxx becuase I don't remember the lower limit. 

Does anyone know the reason behind this requirement?  Obviously I wouldn't setup in cruise at 2300 for a long xc, but does a low power decent at 2300 for 5 minutes in an approach pose any risk?

I have a new Hartzell Prop on the plane, limitation is now no continuous 2350-2550 above 24inch. 

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31 minutes ago, Buckeyechuck said:

I normally practice approaches at 23” mp and run the prop at the low end of the of the green arc. I assumed that was 2300. 

My C is redlined 2000-2250. When flying low on shirt trips, I use 23"/2300. But check your Manual and look at the stripes on the tach.

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From the MAPA PPP last September, the book MAP and RPM for the FAF were taught to us to be about 2350 RPM (just out of the yellow line for my 65 E model) and about 15" MAP.  Those setting put the speed about 120 MPH.  My flap limit is 100 MPH so, no go there.  As well, the book stipulates the gear as Down at the FAF - (or, for me, on the downwind if a VFR approach).

Before this training, the first of three GUMPS callouts hung it all out there well before the FAF.  The gear was down before the FAF and I had FULL FINE on the RPM and then used the throttle to keep it below 100 MPH from the FAF on down through the DH/MAP to the actual touchdown (cheater method of ensuring the aircraft is ready for go round with only throttle to move).  When visual was attained before the DH or MAP, then flaps could come down then.  3 GUMPS checks called before the DH/MAP.

Now, after this training, I am trying to use the recommended settings, but besides messing up my previous GUMPS callouts, I have to mess with the Governor to FULL FINE only on reaching DH/MAP (or visual acquisition whichever comes first) and dropping the gear ONLY at the FAF still throws my anchors out into the wind well before the DH/MAP (still don't like what it does to my GUMPS callouts).

Not yet fully in muscle memory yet. 

But to answer the question - not at or before the FAF for flaps and only two pumps when runway acquired.

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On 1/26/2019 at 12:21 PM, Ned Gravel said:

From the MAPA PPP last September, the book MAP and RPM for the FAF were taught to us to be about 2350 RPM (just out of the yellow line for my 65 E model) and about 15" MAP.  Those setting put the speed about 120 MPH.  My flap limit is 100 MPH so, no go there.  As well, the book stipulates the gear as Down at the FAF - (or, for me, on the downwind if a VFR approach).

I tried this Sunday.  The O360 in the C won't turn the prop at 2350 rpm with 15" of MAP.   It took something like 17", which resulted in about 85-90 kt with gear down while on the final descent.

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