Approach - prop full forward: when?

[lithium366]

Ok so this is probably not a very Mooney specific question but what I found is that CFIs that transitioned me to complex and Mooney didn’t seem to care about this aspect and surprisingly I can’t find any information about the subject

Context: M20E on approach. What I do is reducing MP / RPM to 17.5”-19” at 1950RPM in a terminal area or when it is time to slow down (normally 2000 ft above the pattern altitude or 5 mins prior to reaching FAF. I read that a lot of pilots keep RPM at 2400-2500 but I found that reducing it keeps an engine warmer per Zef article and also keeps the bird quieter. Then I drop the gear and half flaps and that gives me 90MPH with settings I mentioned. Electric pump, mixture - rich, start pushing the prop (well, actively rotate, as I being told that I should avoid pushing it forward too fast) and... wow, RPM is increasing, passengers have no clue what’s going on, kind of awkward for RPM to increase on final. Unless I reduce MP below 15” in advance so governor can’t longer maintain required speed. 

How do you guys manage prop speed on final? How do you avoid an RPM increase (following Zef technique) and when exactly you prefer to push prop forward considering safety when you might need to promptly increase power:  1. In the pattern 2. On a precision approach?

[jetdriven]

When I detect the prop is no longer governing at the set speed then I push it forward..  also then set the mixture as well. 

[gsengle]

Short final. Part of final gear down check. You push it forward in case of go around... that’s my flow.


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[Captnmack]

So the thinking is that you do not want to be that pilot who makes noise when the pitch changes so my suggestion is to go to full when you have the least amount of throttle . That way the sound profile is reduced....

[Immelman]

+1 to jetdriven's technique.

Once out of the governing range... pushing it forward will have no effect, unless you add a bunch of power.

[carusoam]

Full rpm is...

1) a braking mechanism. (Like downshifting in a car...)

2) a get ready mechanism. (Like getting ready for a go around...)

3) Part of gumps check...

4) The rpm is set slow-ish for descent by many Mooney Pilots... it improves glide efficiency, lowers drag...  when the need for efficiency is completed, increase the rpm for the next phase of flight...

Use high rpm when warranted...

PP thoughts only, not a CFI...

Best regards,

-a-

[lithium366]

Your answers make me thing that I was trying to push prop forward too early... somewhere in a downwind to base turn when I still want more power 

[McMooney]

2300 and 18 to 20 mp between iaf and faf

half flaps about halfway to faf

just prior to FAF,  gear down, prop full in , flaps,  mixture full in, gear down, gear down.

after FAF only worry about landing or going missed. 

if guaranteed landing may add more flaps but that's the only real config change I will make after the faf

 

 

 

Edited August 3, 2019 by McMooney

[lithium366]

Just now, McMooney said:

2300 and 18 to 20 mp between iaf and faf

half flaps about halfway to faf

just prior to FAF,  gear down, prop full in , flaps,  mixture full in, gear down, gear down.

after FAF only thing I do is worry bout landing or going missed. 

if guaranteed landing may add more flaps but that's the only real config change I will make after the faf

 

 

 

That’s what my thinking is - do everything in advance and stay ahead in a critical phase of flight. But looks like you not concerned with the RPM increase prior landing? I am new to complex and as I said that RPM increase prior to landing looks awkward to me. I feel like by increasing a gap between MP and RPM i’m cooling the engine more that I need to

[McMooney]

on an approach, the plane is still making power until idled on final and runway is made.

don't think it'll get overly cool.

[Andy95W]

15 minutes ago, McMooney said:

 

just prior to FAF,  gear down, prop full in , flaps,  mixture full in, gear down, gear down.

after FAF only thing I do is worry bout landing or going missed. 

 

You can fly your airplane any way that you want for whatever reasons you feel are important.  But if you fly exactly like McMooney said above, then you can fly with any professional pilot in the world and they won't second guess your technique or your reasons.

(If you fly a vintage Mooney like mine with a flap speed of 100mph, you'll probably stick with zero flaps.)

[lithium366]

Thank you guys. I feel way more confident now after your advises. The fact that my vintage POH is about 20 pages makes me a bit nervous at times. Especially because there is not much info in the checklists, emergency procedures, take-off and landing performance information

[lithium366]

13 minutes ago, Andy95W said:

You can fly your airplane any way that you want for whatever reasons you feel are important.  But if you fly exactly like McMooney said above, then you can fly with any professional pilot in the world and they won't second guess your technique or your reasons.

(If you fly a vintage Mooney like mine with a flap speed of 100mph, you'll probably stick with zero flaps.)

I found it hard to slow down below 100mph with no flaps unless idling. What is your power setting / descent rate for no flaps landing?

[carusoam]

Ilya,

For the lack of info challenge...

1) Get the most recent version of the POH for your M20E... is is probably dated 1977... and applies directly to all M20Es... the POH just got more complete every year...

2) To get a feeling for how much info is missing... Find the most recent POH for an M20J... of course the info is not directly related to the M20E... but some things you can adapt for yourself...

3) The OM for the M20C was like 40 pages... the M20R got 300 not including supplements... so there are about 200+ More pages of info that a modern M20C would get...

4) For IFR procedures get the MAPA training manual, attend a MAPA event... and enjoy the insurance discount...

PP thoughts only, not a CFI...

Best regards,

-a-

[Andy95W]

I'm normally about 17"/2400 rpm at midfield downwind or just prior to FAF.  That gives about 115 mph so I can drop the gear.  After gear down, I go prop full forward like McMooney said.  Don't worry about your passengers. They're probably freaking out anyway because they can't see the ground and they can tell you're keyed up for the approach.  After that not much adjustment is needed on throttle to hold 110 or so down the ILS glideslope, flaps up of course (100 mph flap speed).  I use whatever power setting I need to hold glideslope and 100-110 mph.

I don't get too wrapped around the axle about exact power settings because it'll vary depending on headwind.  Your trim will set your speed, your throttle will keep you on glideslope.

[Bob - S50]

I'm like many others here except I don't really do a "GUMPS" check.  Instead, I do a GFP check (gear, flaps, prop) as I've already selected my fuel tank approaching the field and I leave the mixture lean during approach and landing.

So that means I'm checking the prop full forward after I've got full flaps.  I'm almost always at a very low power at that point anyway so prop speed is being controlled by the throttle rather than the prop control.  That being the case I can shove the control forward as quickly as I like.  The way I fly my VFR patterns that means I'm usually doing that just before I turn base.  During instrument approaches I usually fly about 75 - 90 KIAS and half flaps.  Once I'm below the weather and as low as minimums I'll go to idle and add full flaps while I slow to final speed.  That's when I push the prop and do my GFP check.

[PT20J]

The only reason for advancing the prop control is to have full power available for a go around. So, any point before going around is OK. Pick a low workload time.

To avoid rpm surges and noise, it’s best to push the prop control forward when the prop is out of the governing range and against the low pitch stops. This is a function of throttle setting and airspeed. A little experimenting will determine this.

If you are out of the governing range, it doesn’t matter how fast you push the control forward since it doesn’t have any effect on the prop. It’s generally not a good idea to screw vernier controls all the way into the stop as you can put the cable in compression. 

Skip

[midlifeflyer]

1 hour ago, PT20J said:

The only reason for advancing the prop control is to have full power available for a go around. So, any point before going around is OK. Pick a low workload time.

To avoid rpm surges and noise, it’s best to push the prop control forward when the prop is out of the governing range and against the low pitch stops. This is a function of throttle setting and airspeed. A little experimenting will determine this.

If you are out of the governing range, it doesn’t matter how fast you push the control forward since it doesn’t have any effect on the prop. It’s generally not a good idea to screw vernier controls all the way into the stop as you can put the cable in compression. 

Skip

Exactly.

 

13 hours ago, lithium366 said:

probably not a very Mooney specific question

Also true. VFR, my normal descent from pattern altitude with a constant speed prop (even without retractable gear) is to reduce power, hold altitude to slow to my target airspeed, deploy initial flaps, and, since that reduction is typically out of the governing range, push the prop full forward. .

[Immelman]

On 8/2/2019 at 9:56 PM, lithium366 said:

I found it hard to slow down below 100mph with no flaps unless idling. What is your power setting / descent rate for no flaps landing?

Fly straight and level and play with it. You will see you need much more than idle to maintain altitude and 100mph.

However the prop maybe against the low pitch / high RPM stop (out of the governing range) and thus the RPM somewhere less than commanded....but above windmilling.

Therefore, the selected prop RPM doesn't really matter. As someone said above, its a "get ready" setting in case you need to add a bunch of power or go around.

[Yetti]

pull the throttle back on decent.  You have x amount of energy at threshold.   The goal is to manage that decreasing energy to touch down.   You have throttle, flaps, and gear and maybe speedbrakes.   I was taught to never touch the governor from cruise to touch down.    Shove everything forward if you need a go around.   If the wind is blowing hard then I might use a tinesy bit of power to make the runway.