How to fly below the Va if you have to

[hazek]

Simple question. My plane doesn't fly below max Va at the lowest possible power setting before the gear horn of 20" and 2200RPM and that's just with me in it. I was doing about 135 KIAS at that power setting with gear retracted. But with just me the Va is lower, possibly towards the lower end:

On my last flight I was at around 1315kg and to be below 117 I had to put down the gear and throttle even further back to around 18". Is that what I'm supposed to do in turbulence?? Am I supposed to put the speed brakes out rather than gear and fly like that?

POH in the topic:

I mean sure, slow down. But how if the plane just wont? I mean it could if I throw down the gear or use speed brakes but that seems excessive.

Any input appreciated!

[N201MKTurbo]

I think you need to adjust your gear horn. 20” seems kind of high.

[hazek]

Ha, you're right:

I'll check this. Thanks.

[hazek]

Ok one other question then. On my last flight I started getting the horn (at least I think this is the gear warning horn right?: peep peep peep peep..) as I was about to level off after my descent at 20" 2000RPM and Peak TIT for entry to traffic pattern. I started to enrichen the mixture and I started getting the peep peep warning and then I increased RPM and finally increased the MP by just an inch, maybe not even that, and the horn stopped.

How could enriching the mixture cause the horn to trigger. Per the service manual it's tied to a MP setting. I recorded my flight with a GoPro so I'm 100% sure about what I'm saying. I started enriching and mid way through the peeping started. Then I increased RPM to 2200, I can see the MP drops by one inch or so at this point and then I increased the throttle by a smidge, somewhere between one turn and half turn, and the peeping stopped. Does going richer from peak TIT somehow decrease MP? I guess if I enriched past best power to the richer side, power reduces and so less suction means lower MP? Is that what happened? Looking at this:

I would have needed to go basically full rich to be at a lower power output mixture than peak TIT. This is really confusing to me.
If someone can confirm that peeping is the gear horn, and how enriching can trigger it that would be great.

[N201MKTurbo]

I’m not very familiar with the Bravo, but from the POH statement, I suspect it uses a throttle switch. So nothing matters except your throttle position.

[Rick Junkin]

35 minutes ago, N201MKTurbo said:

I’m not very familiar with the Bravo, but from the POH statement, I suspect it uses a throttle switch. So nothing matters except your throttle position.

This is correct. The gear warning horn should be either on or off and not changing unless you change the throttle position. It sounds like the bracket that the throttle position micro switch is mounted to is loose and floating around a bit, or something is interfering with it when you make other adjustments.

[Rick Junkin]

37 minutes ago, Rick Junkin said:

This is correct. The gear warning horn should be either on or off and not changing unless you change the throttle position. It sounds like the bracket that the throttle position micro switch is mounted to is loose and floating around a bit, or something is interfering with it when you make other adjustments.

Here’s a picture of the bracket. The microswitch is mounted to the back of the bracket, and you can see the wheel of the microswitch that rides on the throttle cable in the red circle.

There is a second microswitch in the same area that turns on the boost pump at full throttle. Don’t confuse the two. The boost pump switch does NOT ride on the throttle cable.

The bracket is located on the bottom right side of the rear of the engine beneath the oil cooler and air ducting.

[Rick Junkin]

5 hours ago, hazek said:

Simple question. My plane doesn't fly below max Va at the lowest possible power setting before the gear horn of 20" and 2200RPM and that's just with me in it. I was doing about 135 KIAS at that power setting with gear retracted. But with just me the Va is lower, possibly towards the lower end:

On my last flight I was at around 1315kg and to be below 117 I had to put down the gear and throttle even further back to around 18". Is that what I'm supposed to do in turbulence?? Am I supposed to put the speed brakes out rather than gear and fly like that?

POH in the topic:

I mean sure, slow down. But how if the plane just wont? I mean it could if I throw down the gear or use speed brakes but that seems excessive.

Any input appreciated!

In answer to your primary question, my technique is to deploy speed brakes at minimum power for conditions and slow to Va, then retract brakes and adjust power to hold the desired airspeed.

Once you get your gear warning switch properly adjusted you will be able to get down to 18” or less without triggering the gear warning.

Now I have a question . 135KIAS at 20”/2200 in level flight sounds fast. That’s my power setting for pattern entry and I get about 115-120KIAS in level flight, LOP. Have you had your airspeed calibrated recently? Or cross-checked it with calculation against GPS ground speed? I’m not saying it’s wrong but if correct then your airplane is way slipperier than mine!

[hazek]

2 hours ago, Rick Junkin said:

This is correct.

Ok found it:

But it's not depicted here or is it the encircled part?

Plus based on this I don't see how me changing the mixture could have changed anything.

Oh and the MP gauge under reads by about 1 in. so perhaps I was at 21-22" and 2200 RPM doing 135.

 

Edited February 25 by hazek

[hazek]

From the parts catalog:

That doesn't look like the same schematic. Hmm

[Rick Junkin]

 

1 hour ago, hazek said:

Ok found it:

But it's not depicted here or is it the encircled part?

Plus based on this I don't see how me changing the mixture could have changed anything.

Oh and the MP gauge under reads by about 1 in. so perhaps I was at 21-22" and 2200 RPM doing 135.

 

The part you have circled is the throttle position microswitch for the gear warning. Here are the appropriate pages from the IPC. The bracket is #8, the microswitch assembly is #13.

My guess is that either the bracket/switch is loose and moving around, or there's possibly interference with the throttle cable from something else that's moving and causing the throttle cable to flex. From your description it sounds like the switch, bracket, or throttle cable position need to be adjusted so that the switch is actuated 1/4" from the throttle idle position. Once you are able to get that right it may remove any other issue that's causing the switch to actuate.

My gear warning stopped working because the roller on the microswitch arm had developed a flat spot and didn't have enough throw to actuate the switch. That's something else to look at that could be causing variability in your system.

 

[hazek]

Alright, thank you! I think I have my answers.

[Fritz1]

my gear warning comes on at about 19", this feels about right, I will not go below that power setting in a descent unless gear is down, you want to avoid the engine driving the propeller, the gear warning is a good reminder, at 19" the engine is still putting power into the propeller in a 500-750 ft/min descent with the gear up

[hazek]

8 hours ago, Fritz1 said:

my gear warning comes on at about 19", this feels about right, I will not go below that power setting in a descent unless gear is down, you want to avoid the engine driving the propeller, the gear warning is a good reminder, at 19" the engine is still putting power into the propeller in a 500-750 ft/min descent with the gear up

Yes sure, for that it makes sense.  I too don't go below 20"/2000 in a descent and for the same reason. But then how would you answer my original question?

[Fritz1]

speed brakes are simple and effective, once your speed is where you want it to be retract them or put the gear down, my airplane has TKS and will not reach Va at 20/20 in horizontal flight, yours is exceptionally fast 

[jetdriven]

On 2/25/2025 at 6:06 AM, hazek said:

Simple question. My plane doesn't fly below max Va at the lowest possible power setting before the gear horn of 20" and 2200RPM and that's just with me in it. I was doing about 135 KIAS at that power setting with gear retracted. But with just me the Va is lower, possibly towards the lower end:

On my last flight I was at around 1315kg and to be below 117 I had to put down the gear and throttle even further back to around 18". Is that what I'm supposed to do in turbulence?? Am I supposed to put the speed brakes out rather than gear and fly like that?

POH in the topic:

I mean sure, slow down. But how if the plane just wont? I mean it could if I throw down the gear or use speed brakes but that seems excessive.

Any input appreciated!

VA doesn’t have much to do with turbulence, that’s the maximum speed you can input any single control input without damaging the airframe. The top of the green arc relates to turbulence. And the Mooney is very strongly built, so keep it out of the yellow in rough turbulent air. 
Don’t make any full control inputs  above VA.

[hazek]

19 hours ago, jetdriven said:

VA doesn’t have much to do with turbulence, that’s the maximum speed you can input any single control input without damaging the airframe. The top of the green arc relates to turbulence.

All the sources I could find say this not to be correct. Example:
https://www.avweb.com/flight-safety/technique/turbulence-v-speeds/