Vfe/Vfo for 10 degrees?

[dkkim73]

Hi all,

I looked for, but did not find POH guidance on whether the first notch of flaps can be extended above the top of the white arc on the Acclaim. 

All of the verbiage talks about full flaps. 

I'm trying to work out reference power settings and a "dirtying-up" protocol for different approach phases, and would appreciate any guidance here. 

Thank you,

David

[FoxMike]

Years ago one of Mooney's top salesman told me an unpublished number for deploying 10d flaps was 137Kts indicated.  At the time I was on a demo flight in a TN.    I do not use 137 in my Bravo but 120/125 seems to e OK.  I find dropping the gear slows the airplane adequately.  Somewhere around 100/110 I feel the need for the 10d of flaps.  Personal choice in my opinion.  

[M20TN_Driver]

My acclaim is placarded at 110kts for flaps

[dkkim73]

That 137 KIAS number feels familiar. I kind of remember a "best speed to the FAF" approach in my transition training (we did it at 170KIAS), and I think I remember dropping the first notch of flaps not far below gear speed Vlo(down). However I can't find a good reference. 

Experimenting with approach reference speeds of 90 or 120 inside the FAF, as the math works well. With the trim change that flaps entail, I'm looking for a good rhythm that doesn't invove a lot of changes getting near minimums (ok in VMC but in IMC I'd rather front-load the config changes)... While the AP seems to do a good job of staying on GS/GP during changes, it doesn't feel as compartmentalized as getting "approach flaps" in earlier. And manually flying involves some juggling with the nose-down moment. 

And of course it's good to be able to fly the approach faster or slow based on need. It's not that I "need" to keep fast inside the FAF most of the time, but definitely times it is useful. 

Thx for the quick responses!
David

[PeteMc]

Check you POH again.  My guess is it says FULL FLAPS for the Max speed.  I've been told by multiple high time instructors that if you want to put a little bit of flaps in for drag or whatever reason, it is NOT prohibited.

 

[FoxMike]

I used to own a T210.  The M model allowed 10d of flaps below 140Kts.  

[Shadrach]

12 hours ago, M20TN_Driver said:

My acclaim is placarded at 110kts for flaps

And that agrees with the TCDS. Which is the final authority on the subject. 

There is no approved higher speed for partial flap deployment. Logic would dictate that one could deploy partial flaps at some speed above Vfe without generating the aerodynamic loads encountered at max extension at Vfe, nevertheless, anyone doing so is playing test pilot though the stakes are quite low compared to other stupid pilot adventures.  To be clear, I think most airplanes have exceeded Vfe at some point in their lives though likely not intentionally, but accidentally during busy, single pilot operations.

[PeteMc]

3 hours ago, Shadrach said:

There is no approved higher speed for partial flap deployment.

I just happened to search through one of the PPP manuals and it has a section that states "...Some M20J/205s allow higher speeds for up to 15dgr flap extension."

So as I had said, check your POH for your specific plane. 

 

[Shadrach]

16 minutes ago, PeteMc said:

I just happened to search through one of the PPP manuals and it has a section that states "...Some M20J/205s allow higher speeds for up to 15dgr flap extension."

So as I had said, check your POH for your specific plane. 

 

It is listed in that models section of the TCDS.  I don't have all the POHs in my files and don't need them as it is clear in TCDS 2A3 that M20Js with Serial Number 24-3000 thru 24-3078 are approved to deploy 15° flaps at 145 m.p.h. (126 knots) IAS.  As far as I know it is the only Mooney model ever certified with an increased Vfe for partial flap deployment.

[kortopates]

It is listed in that models section of the TCDS.  I don't have all the POHs in my files and don't need them as it is clear in TCDS 2A3 that M20Js with Serial Number 24-3000 thru 24-3078 are approved to deploy 15° flaps at 145 m.p.h. (126 knots) IAS.  As far as I know it is the only Mooney model ever certified with an increased Vfe for partial flap deployment.

That’s correct, it was approved for a small number of J’s and then Mooney went back to not providing a higher v-speed for partial flaps in the latest J models.

But it’s a great example that if there was an approved higher v-speed for partial flaps then it would be listed in the TCDS and POH as it is for those J models.
The argument that the POH specifies a Vfr for “full flaps” must imply a faster speed for partial flaps is a hollow one.

This has come up 3 or 4 times probably in the last 5 years often with hundreds of posts which merely proves pilots will continue to interpret their POH however they want.


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[Danb]

Our POH’s should be clear and explicit my Acclaim POH is detailed in performance aspect but lacks in other areas. I’ve had 1977 J 1988 j 2005 M and now a 2016 TN the POH is ambiguous at best in many ateas

[dkkim73]

1 hour ago, kortopates said:

The argument that the POH specifies a Vfr for “full flaps” must imply a faster speed for partial flaps is a hollow one.

This has come up 3 or 4 times probably in the last 5 years often with hundreds of posts which merely proves pilots will continue to interpret their POH however they want.

I will say it's an inviting ambiguity in the POH (how hard would it be to say "no flap deployment above 110KIAS is permitted"?), but the lack of specific guidance gave me pause. Wishful thinking is the siren song of aviation. 

I will rely on the dive brakes and gear above the white arc...

[Shadrach]

1 hour ago, kortopates said:

But it’s a great example that if there was an approved higher v-speed for partial flaps then it would be listed in the TCDS and POH as it is for those J models.
The argument that the POH specifies a Vfr for “full flaps” must imply a faster speed for partial flaps is a hollow one.

It's a hollow argument from a regulatory standpoint which is all that matters. There is a physics argument to be made but it's navel gazing from an operations standpoint unless one is willing to make up their own rules and disregard certificate limitations.

[Shadrach]

32 minutes ago, dkkim73 said:

I will say it's an inviting ambiguity in the POH (how hard would it be to say "no flap deployment above 110KIAS is permitted"?), but the lack of specific guidance gave me pause. Wishful thinking is the siren song of aviation. 

I will rely on the dive brakes and gear above the white arc...

Cry me a river...my Vle is 120mias and Vfe is 100mias. 

[dkkim73]

53 minutes ago, Shadrach said:

Cry me a river...my Vle is 120mias and Vfe is 100mias. 

Are you in a Sopwith Camel?  Or.... an Arrow? 

I would have assumed from your prior posts you could just bend the laws of physics or fabricate a workaround. I'll stop whining now. 

[Shadrach]

31 minutes ago, dkkim73 said:

Are you in a Sopwith Camel?  Or.... an Arrow? 

I would have assumed from your prior posts you could just bend the laws of physics or fabricate a workaround. I'll stop whining now. 

I operate well within the laws of physics. The edges make me nervous…

Those of us in vintage birds have to developed work arounds. I had never done an ascending forward slip until I started flying Mooney.

With no speed brakes cross controlling is a regular part of my flying around small dromes with smaller patterns and shortish runways.