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My Mooney is too fast.


Glen Davis

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Today I flew from Central Maine to an airport in the New York City area. I was IFR on top of a solid cloud deck at 6000 feet. I asked for lower as I was getting close to my destinations airport, in the class bravo, and I was planning my approach but ATC could not give me lower when asked. Finally, about 15 miles prior to the initial approach fix they gave me 3000. I lowered the nose to give a 500 ft./min. descent and as expected the indicated airspeed increased to approximately 165 knots.  I was in the soup and getting bounced around and wanted to slow down closer to maneuvering speed. I reduced the manifold pressure 13 inches and brought the prop back to 2200. Still I was too fast for the rough ride I was experiencing. Other than leveling off and letting the indicated airspeed bleed off to gear extension speed, then lower the gear, what else can one do to slow down  when in turbulence and on a dissent. I don’t have those funny things that pop out of the wings to help.  Glen

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Next time slow first and then lower gear and just fly it like a 172, or tell approach “unable” explain that you can’t descend that steep and let the vector you, they will be pleased. but don’t let them put you into a unsafe situation

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Next time, slow down before starting your descent.  It's a math game. At 165kts and 500fpm, you will travel just under 3 miles a minute. You'd need ~17 miles to lose 3000' at that speed.  At 100kts, you'd only need about 10. Pull the power back. Slow down. It happens quickly. First notch of flaps and gear, you'll be coming down quickly while covering minimum distance.

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My thought is the same, should have slowed way down in cruise, knowing how close you were getting. I sometimes  let ATC distract me too, but I think the idea of thinking in front of the airplane and the system, would have warranted pulling power way back once you understand you’re about to get a slam dunk. 165 ias descent in the soup is no bueno, for me. 

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Ways to slow a Mooney down…

All work….

1) pull back power… maintain CHTs if it is super cold out…

2) push in prop… exactly like grabbing a lower gear, without the unnecessary skidding tail slide…

3) lower gear… gear operating speeds apply

4) increase to gear down speed…. Gear down is a giant speed brake.   Everyone here has a set.

 

5) use speed brakes if you have them… good to deploy up to Vne…. Check your POH…

 

6) Methods people use when discussing E-descents…. Works the same when trying to slow 

7) These all have one thing in common…. They are methods of turning kinetic energy into waste by using friction….

8) Pulling the prop back?  No need to waste energy in a pseudo efficient manner… :)

9) Continue to monitor your engine…. So you don’t become overly concerned about OWTs like driving the engine with the prop… or super cooling your cylinders….

10) When you have done all that and still can’t slow down….  Key word is ‘unable’

11) Planning in advance… knowing your plane… communicating your needs with ATC before they become an emergency… is better than just saying unable…

Pp thoughts only not a CFI…

Best regards,

-a-

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I don't have speed brakes on my 310.  It's slick like the Mooney. I can push the nose over and easily get 220kts indicated. I don't have speed brakes and I can't put flaps in until 158kts. In a descent, that's essentially never going to happen. I usually cruise in the teens, so I have to plan descents.  I know when I *have* to start down and if ATC hasn't started me down by 10+ miles before that, I start slowing.  Going slower buys time.  Be ahead of the plane. 

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Now that’s the first time I’ve ever heard anyone complain about our Mooneys being too fast!  :) 

I have speed brakes, but landing gear are much more effective in slowing down than speed brakes are. They also help stabilize the airplane in turbulence.  Add flaps in a descent and you have a very controlled descent airspeed. If I know I’m about to get a huge descent (as I often do around my airport being around a class bravo shelf I.e. vectored abeam airport at 8,000 feet agl!)I slow down gradually well before then, being ahead of the airplane with power below gear speed, drop gear, then when I get the descent, I’m ready. Sure speed brakes help do this faster but I can do it with gear and power without much difficulty planning ahead. 

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Welcome to NYC!  Often coming from the south to KFRG they'll keep you high until you pass JFK, then suddenly dump you.

As others have said when coming into NYC area (or any metro area) where they're keeping you high, I've always started slowly pulling the power and I just keep slowly pulling it as I get closer.  I just keep looking at where I am and how much power I'd want to descend from HERE.  Eventually, like V1 @ 4-6000 over JFK, you can only pull back so far.  But then you're plenty slow enough (for you) to use your speed brakes and for me to drop the gear.

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Coming from the East to 39N…

Energy management from above the NYC Class B is key…

About 30nm to get rid of the 8k’ of altitude…

Depending on who is deciding on your altitude assignments…

Around your own home drome… you get to learn some key waypoints and altitudes you want to be at before wasting the excess energy…

Bumps and maneuvering speeds add to the challenge…

PP thoughts only, not a CFI…

Best regards,

-a-

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You can just decrease your descent rate to 1-200 fpm momentarily and that should let you get to gear speed  

Another option is that big old rudder can help slow you down. Enter a forward slip and pull the nose up slightly.  You will slow quickly to gear speed. You’re using the entire side of the fuselage as a speed brake. 
 

Prop coarse will decrease drag.  But your robbing Peter to pay Paul in some respect- most folks would not advocate for fine pitch and low MP such that the prop is driving the engine - esp if it’s a counterweighted engine.  
 

As others have mentioned the best advice is be ahead of the airplane.  New York approach controllers are literally the best out there.  They don’t do slam dunk approaches.  They also appreciate you telling them what you need and if you’re unable to do what they want, “unable”.   But NY are like sharks in a way - you hesitate or stumble on the radio and they sense a struggling fish and will bite.  Know - exactly - what you want, fit in with the cadence of the frequency, and you’ll get it if it can be accommodated. 
 

“New York, Mooney 123, needs to slow for turbulence, unable XYZ IAF at 3000, request a short vector for descent.”  

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My problem every summer descent.  I'm well into the yellow when I start hitting the bumps, not much I can do to get back in the green short of level off and drop the gear.  I'm in a Mooney, I'm not spending time flying like a Skyhawk unless I have to.  I suspect my Mooney has been doing this for a LOT of years.  Damn things are built stout. I just keep going.

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Vle on the acclaim is 164 KIAS.  Yours should be similar.

speed brakes shed approx 20KIAS everything else constant. Gear extended is about the same I think.

so next time, try to get to Vlo, drop the gear, pull the power, and pitch for Vle.

-dan 

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Some great advice. Thanks all.  Dropping the gear before I start the descent is a great idea and then increasing to Vle would probably work perfectly. Also, asking the controllers for a vector because I am unable to descend due to turbulence is another great idea. But flying my Mooney in the yellow arch while in turbulence is not for me, as “stout” as it is. I feel that’s tempting fate. Call me a coward!

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Maybe it’s just me, but I think operating anything right at max allowable speed as possibly causing more stress and wear than is necessary. In a similar vein to operating cyl head temp at 400, I think most understand why that’s not a good idea, well extrapolate that out to all of the other limits.

‘I think we are a CAR 3 airplane, and in CAR 3 there is no accounting for age and fatigue.

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Maybe it’s just me, but I think operating anything right at max allowable speed as possibly causing more stress and wear than is necessary. In a similar vein to operating cyl head temp at 400, I think most understand why that’s not a good idea, well extrapolate that out to all of the other limits.
‘I think we are a CAR 3 airplane, and in CAR 3 there is no accounting for age and fatigue.

I think the gear limit is about stress on the gear doors and associated hardware. I think our gear is robust enough to handle any speed below yellow.
But I agree, I try not to test the limits.
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On 6/27/2021 at 5:57 PM, Glen Davis said:

 Finally, about 15 miles prior to the initial approach fix they gave me 3000. I lowered the nose to give a 500 ft./min. descent and as expected the indicated airspeed increased to approximately 165 knots.  I was in the soup and getting bounced around and wanted to slow down closer to maneuvering speed. I reduced the manifold pressure 13 inches and brought the prop back to 2200.

Keep the prop full forward.  This will provide more drag in the descent.

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