Instrument approach speeds and manifold settings for J owners

[DonMuncy]

3 minutes ago, carusoam said:

Don,

I think your post got misplaced...?  

Sounds like an answer to the O2 tank leak somewhere in a different thread...  

Best regards,

-a-

Thanks. Of course you are right. I tried to correct it, and moved it to the correct place.

[jaylw314]

On ‎1‎/‎15‎/‎2017 at 9:01 AM, teejayevans said:

At 2000 rpm and 17" I would be doing 113 knots in level flight, y'all must be pulling back power to get such slow approach speeds. I prefer 100 knots at FAF, it's more responsive and gives me a greater margin of error in case of wind shear. Only after breaking out do I slow it down for landing. I've had the stall horn squawk once on in IMC while getting bumped around, now I keep my speed up.

I shoot for 90 knots at the FAF.  One benefit is that it's easier to do mental math for a timed MAP--If the time for 60 kts is 6:00 min and 120 kts is 3:00 min, the time for 90 knots is 4:00 min.

[xcrmckenna]

This Saturday I am scheduled to fly with a CFII to start my IR training. Ive been practicing approaches into my home Airport for the past year and still have trouble slowing the plane down from VECUC to the MAP.

 

It’s a long ways down from 8000’ msl. I’ve gotten into the habit of just dropping the gear at VECUC and that normally keeps me at 90KIAS and I hit the LPV glide slope just a little low or right on it depending on head wind. I was wondering if that is a reasonable technique for this approach or should I slow the plane down with the gear up till I get to the FAF?

 

Ive wrote down everyone’s engine settings and we will try them out this weekend. 

[carusoam]

XCR...

Are you familiar with the MAPA PPP training?

Their Manual is a really nice document for engine settings for all phases of Mooney flight.

Makes a great weekend of training.

Best regards,

-a-

[PTK]

I wouldn’t obsess about airspeed so much. I understand you’re doing it because you drop the gear so early. Try decsending at a somewhat constant slope while slowing down aiming to be at gear speed by the faf. Use speed brakes if you have them. Then at faf gear and then flaps prn.

For a 3° slope a good rule of thumb is to multiply GS by 5 to get fpm descent required. eg. 100 knot GS requires ~500 fpm.

[jetdriven]

One thing I learned from BT was to never add any flaps until the gear is lowered. Half flaps is a similar pitch and drag profile as gear down and it adds risk for a gear up landing.  Especially if you go full flaps.  Then it gets even easier. 

[xcrmckenna]

6 hours ago, carusoam said:

XCR...

Are you familiar with the MAPA PPP training?

Their Manual is a really nice document for engine settings for all phases of Mooney flight.

Makes a great weekend of training.

Best regards,

-a-

I am but the ability to go to one hasn’t came up yet :/ Maybe next year I’ll have the time. 

[smccray]

My plan wouldn’t be to lower the gear VECUC. Depending on ground speeds I would just reduce manifold pressure and maintain attitude to descend. The profile certainly isn’t as easy to fly as a 5 mile level path between the initial and the final approach fix, but that doesn’t look that difficult. If you keep your ias below gear speed you always have the option to drop the gear.

I usually targeted 100 kias. Gear down, intermediate flaps, 12” and 2500 rpm would give me a stable 1000 fpm descent for a non-precision approach. Gear up certainly isn’t going to bring 1000 fpm, but you have 4 miles to get down to 6800, then another 2 miles to get down to 6300 which isn’t that challenging. The profile shows a constant 3.4 degree approach angle all the way from the initial.  If I were going to extend the gear at the initial I would just fly the glide slope all the way down rather than flying step downs to the FAF. 

Edited June 27, 2018 by smccray

[Mooney in Oz]

I think what you are already doing by using the gear to control speed on the way down is the right way to start an approach followed by a constant slope.  Have the aircraft configured and checklist out of the way before the FAF so you can just fly the most critical sector that is between the FAF and MAP.  In my view you are asking for trouble selecting the gear at the FAF followed by configuration and checklist completion as you may have to also deal with other traffic or anything else that can suddenly happen and steal your attention while flying this sector even if it is 7.1 miles.

The best advice I have had is when conducting any type of instrument approach is that I should be bored with everything out of the way giving me plenty of headspace when flying between the FAF and MAP.

[Bike_rider]

Everyone's methods in this post are excellent.  My suggestion is to pick one that works for your situation and "chair fly" it as much as possible.  You may find that you can more easily remember one particular way versus another.  Ensure that it is repeatable and again, practice as much as possible before getting into IMC.  I like to use X-Plane to chair fly my approaches and tweak my technique.  Once you have chosen a method, practiced it, and made it repeatable, then you can apply it in the real world.  Definitely fly in VMC with a safety pilot and work out any variations to make it better for you.  Then you will have the confidence to apply your techniques in IMC.  Also practice a lot of "what if's".  Remember, in the real world, things don't always go as planned.  Good luck!

[Jerry 5TJ]

Flying the RNAV GPS 9 into KGCD in my C or E with their low 120 mph gear limits I believe I would drop the gear at or before VECUC while in level flight.  Otherwise I doubt I could get below 120 to extend the gear while on the 3 degree LPV glideslope.  

[Marauder]

This thread reminds of the attempt to keep a fat lady happy. Should I buy cheeseburgers or will a Philly Cheesesteak do the trick?

 

I would start with the basics. If your instructor hasn’t done so already, make sure you know the power settings that will give you a predictable performance. X MP and X RPM will equal X KIAS. This should include climbs and descents. It also should include a dirty configuration. You should also understand your slowdown power settings to get to your approach speed. Most Mooney owners I know who have issues with stabilized approaches have a hard time making the correct timing decision to slow down, either from a descent to the approach or are flying the legs from the IAF too fast and don’t know how long it takes the plane to slow down.

 

As bike_rider pointed out, although these planes are similar there is some performance differences. Knowing the power settings/configurations for your plane (like carusoam mentioned from the Mooney PPP) is key to flying a stabilized approach.

 

Older models like Jerry’s C/E and my F are different beasts. I have a 109 KIAS VFo/VFe speed and a 104 KIAS VLo/VLe. I don’t have the luxury of dropping gear at 120 KIAS. And I don’t have speed brakes to aid in the descent.

 

Get the airspeed performance nailed down and then determine what configuration/order of deployment makes sense for your plane.

 

On my F, with a higher flap than gear speed, I find the plane is much more stable and likely to stay near my target 100 KIAS approach speed if I deploy them first. At the FAF, I do drop gear and between my known descent profile due to the gear drag and minor MP adjustments I make, I can keep on the 100 KIAS approach speed. If I am flying out to the boondocks and with a known shorter runway, I may go to plan B and further reduce MP to do the final approach at 90 KIAS.

 

 

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[xcrmckenna]

This thread reminds of the attempt to keep a fat lady happy. Should I buy cheeseburgers or will a Philly Cheesesteak do the trick?
 
I would start with the basics. If your instructor hasn’t done so already, make sure you know the power settings that will give you a predictable performance. X MP and X RPM will equal X KIAS. This should include climbs and descents. It also should include a dirty configuration. You should also understand your slowdown power settings to get to your approach speed. Most Mooney owners I know who have issues with stabilized approaches have a hard time making the correct timing decision to slow down, either from a descent to the approach or are flying the legs from the IAF too fast and don’t know how long it takes the plane to slow down.
 
As bike_rider pointed out, although these planes are similar there is some performance differences. Knowing the power settings/configurations for your plane (like carusoam mentioned from the Mooney PPP) is key to flying a stabilized approach.
 
Older models like Jerry’s C/E and my F are different beasts. I have a 109 KIAS VFo/VFe speed and a 104 KIAS VLo/VLe. I don’t have the luxury of dropping gear at 120 KIAS. And I don’t have speed brakes to aid in the descent.
 
Get the airspeed performance nailed down and then determine what configuration/order of deployment makes sense for your plane.
 
On my F, with a higher flap than gear speed, I find the plane is much more stable and likely to stay near my target 100 KIAS approach speed if I deploy them first. At the FAF, I do drop gear and between my known descent profile due to the gear drag and minor MP adjustments I make, I can keep on the 100 KIAS approach speed. If I am flying out to the boondocks and with a known shorter runway, I may go to plan B and further reduce MP to do the final approach at 90 KIAS.
 
 
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You know you are buying a cheeseburger, a Philly cheesesteak, and probably a cheesecake.....


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[Stephen]

On 6/27/2018 at 10:20 AM, Marauder said:

Should I buy cheeseburgers or will a Philly Cheesesteak do the trick?

Assuming no Chili on the burgers, I'd go Philly, but that is just me....