Prop RPM during the approach.

[FlyingOfficerKite]

It all seems to be about 'safety' and standardised SOPs insofar as training for the CPL/IR is concerned - aimed at making sure you don't forget as a number (?) of trainees would probably do if required to go around in those circumstances.

The technique I was taught was to leave the props in the 'approach' setting (typically 2400 rpm initally depending on aircraft type) and then at 500 feet agl carry out the Reds/Blues/Greens finals check.

I have never noticed an increase in prop RPM at that stage of the approach with the normal (say 13" manifold) power settings. Never noticed the speed of the props to be fair - too intent on flying the approach.

This seems to combine the 'safety' issue and the 'care of the propellor' considerations without any trauma.

KR

FOK

[DFC]

and then at 500 feet agl carry out the Reds/Blues/Greens finals check.

To take this back to the original reason for the question - How often when you do this "check" at 500ft do you find that the actions have not yet been carried out?

If what you intended to say is that you carry out the Reds/Blues/Greens actions (flow) at 500ft, when do you do the check that the actions have been completed or is that check not done?

-----

Chuck,

If the POH does not specify at what power setting one should select a higher RPM before landing how do you determine when to increase RPM with regard to the power setting at the time you select the higher RPM?

For instance if you are using a power setting that will result in the RPM surging due to the power being high enough to cause surging of the governor is that O.K.?

Taking the Piper Arrow as an example. This operator's handbook says set 2600 RPM (100 below red line).

If the propeller is out of the governed range then how can one set 2600?

I do not think that anyone approves of shoving the prop lever to the max while at cruise power and resulting in the Max RPM being exceeded while the govenor plays catch-up.

But, smoothly and carefully moving the RPM from 2100 (cruise setting) to 2600 (fine setting) as per the POH can not be done on short final.

[S-Works]

My props go full forward to 1900rpm at about 3000ft.

[Always Moving]

Full Forward For Me

I put them forward after dumping the gear and reducing power FAF or downwind and if you do it slowly you do not hear any noise (and I would think the RPM are out of range already) and hardly ever, a power change is needed (I am talking cabin class twins)

Somebody mention FADEC's I guess they did not listen to the prop going from high pitch to low pitch to high pitch again! (and the first time giving you a heart attack too!LOL the RPM-power curve looks like a drag curve)

I do not like hearing people jamming the RPM indeed CHUCK!

[maxred]

Think I will try that

Looking over BPF post, looks like he is stating that on the downwind, 1000' drop gear, some flap, turn base, mine has Continental IO-470-N, set MP at 15, turn final at say 500', reds/blues greens check, with the prop set at climb - I climb out at 25 squared, therefore should look like 13.5/25. Assuming speed over the hedge is ok, 85kts, then leave the prop alone - i.e it should sort itself out. Have I missed something, or is this a recognised (taught) process?

[S-Works]

I think you have to realise that it has to be horses for courses rather than a dogmatic only 1 way will do approach.

At work, I set flight idle around 3000ft, props full forward to 1900rpm. Maintain flight idle to circuit height then set 18% torque which give me 100kts in the circuit. Turn final, back to flight idle then fly beta which I hold until touch down before full ground beta. You can't put beta in without the props being forward or you will bend the control rods on the engines.

On my Cessna I put the prop forward when I have taken off the power on final as at idle or very low RPM it is outside the governing range so makes no difference but it is one less job to do in the event of a go around.

[Chuck Ellsworth]

DFC somehow you and I are on the wrong page with this conversation so allow me to try and explain what my position is on this subject.

First off if the POH has a requirement for increasing prop RPM on a given airplane then one should follow the procedure as outlined.

Where I stand on this subject is I often see pilots select climb or even worse full RPM when doing their initial landing checks such as downwind for instance resulting in a surge of RPM due to the power setting being high enough to result in the prop changing to fine pitch. Not only is this annoying noise wise it results in unneeded wear on the engine parts.

It has been thirty nine years since I flew a Piper Arrow and can not remember what was in the POH.

Does the POH for the Piper Arrow state at what point in the approach the increase in RPM be performed?

And last but most puzzling to me is why do you think you can't select a higher RPM on short final?

I never had any problem doing that.

[SNS3Guppy]

Turn final, back to flight idle then fly beta which I hold until touch down before full ground beta. You can't put beta in without the props being forward or you will bend the control rods on the engines.

To which powerplants do you refer?

You appear to refer to a turbopropeller motor. What turboprop engine can't be reversed or put in beta with the speed lever or condition lever not forward?

[FlyingOfficerKite]

DFC

In answer to your query - never!

That's one reason I have never landed 'gear up' and the one reason I (hopefully) never will.

KR

FOK

[S-Works]

To which powerplants do you refer?

You appear to refer to a turbopropeller motor. What turboprop engine can't be reversed or put in beta with the speed lever or condition lever not forward?

Walter M601 D-2 Turboprop engines as installed in the DO28 G92 and SMG92.

[DFC]

I asked;

How often when you do this "check" at 500ft do you find that the actions have not yet been carried out?

and FlyingOfficerKite said;

In answer to your query - never!

Which leads me to ask, where then do you do the action of moving the prop to fine so that at 500ft "check" you always find it to be in that position?

-----------

Chuck,

And last but most puzzling to me is why do you think you can't select a higher RPM on short final?

I never had any problem doing that.

If the prop is out of the governed range it is impossible to set a specific RPM unless perhaps one has a gated prop lever.

The whole idea about instructing and examining is not to sit there and think "I never had any problem doing that." because it is about the student / candidate and not about you.

Many of your examples seem to me to show that you like showing your students what you can do with the aircraft rather than teaching them what they need to do with the aircraft. Are you an instructor or a demo pilot?

The fact that you never had a problem with something is irrelevant when it comes to teaching the student / PPL.

[Centaurus]

Gentlemen, I totally agree with you. PUF check was the one I was taught (which amounts to the same thing ; I'm sure there're others):

Ah Yes! The good old Aussie flying school "PUF" check. Except one school goes beyond that and does "PPUFFF" check on short final which means and don't laugh but this is exactly what the poor bloody students are taught by their "professional" instructors.
Pitch - Power Poles - Undercarriage - Flaps - Furry Friends" -and that is for a fixed pitch prop and fixed landing gear type like the Cessna 150...

[Mach E Avelli]

Seems we can summarise all this into:

1. Basic light aircraft, normally aspirated engine with CSU - doesn't matter much when you select fine pitch 'cos it won't damage anything - but select it early enough not to get all crossed-up on short finals and so as not to forget it in the event of a go-around. Because usually those flying this type of machine are in the learning stages, so we don't need to complicate matters.
2. More advanced twins with geared, turbo or supercharged engines and larger radials - keep the M.A.P. up with cruise RPM, adding drag progressively with gear and flaps and leave the props alone until in the flare - in the event of a missed approach; RPM up, power up - GENTLY. Pilots entrusted to this level of aeroplane should be able to cope with the additional complexity of pushing a couple of levers up at the flare or making a smooth transition to a go-around.
3. Turboprops - strictly in accordance with the POH or AFM - which usually requires condition levers to 100% sometime on the approach. Pilots flying at this level will probably be bound by a checklist and company SOP that says so.
4. If it is a rental aeroplane - whatever the owner/operator requires. It's their engine overhaul cost.

[Chuck Ellsworth]

Finally after five pages of opinions, ideas, guesses and I fly this way because that is how I was taught someone has pretty well summed it up fairly accurately..

Now Mach E Avelli all we need is for you to jump over to another thread I started and sum up what a flight instructor is.

[SNS3Guppy]

3. Turboprops - strictly in accordance with the POH or AFM - which usually requires condition levers to 100% sometime on the approach. Pilots flying at this level will probably be bound by a checklist and company SOP that says so.

Most turboprop engines have no need to be advanced on the approach, or even after landing, or in beta or reverse. One may do so, but there's no specific need in the case of most turbopropeller powerplants and installations.

[Mach E Avelli]

The RR Dart is one engine that you can not advance RPM without a corresponding power increase in flight, because it is a single lever throttle/prop control. However, once on the ground and in ground fine pitch, if you can develop the technique of advancing the RPM back up from idle (about 7500 rpm I recall) to a bee's dick under 10,000 it does two things - increases windmilling drag slightly (prop stays at zero degrees blade angle) and allows the engine to run cooler. Never seen it published anywhere, but you can certainly see the result on the TGT gauges.

[Big Pistons Forever]

Originally Posted by Chuck Ellsworth

Finally after five pages of opinions, ideas, guesses and I fly this way because that is how I was taught someone has pretty well summed it up fairly accurately..

Now Mach E Avelli all we need is for you to jump over to another thread I started and sum up what a flight instructor is.

I second Chucks comments. An excellent and sensible summary of the issue by Mache E Avelli's

So Chuck does this mean you now agree with point one of Mach E Avelli's post. That is for low time pilots advancing the prop to a higher RPM well in advance of the flare is:

1) Not going to damage the engine in any way, and

2) Desirable in that it recognizes that it is reasonable to stagger tasks so as to avoid overloading low time pilots in high workload phases of flights

[Centaurus]

If it is a rental aeroplane - whatever the owner/operator requires. It's their engine overhaul cost.

Careful, here. I have seen owners that paste little notices in the cockpit of the aircraft they are hiring out, that purport to be the good gen engine handling perceived by the owner - but which in fact are totally contrary to good airmanship. The pilot in command decides how he will fly that aircraft - not the owner. Just ask the lawyers.

[MungoP]

What we teach is that (PT6) we need the props forward to achieve full power in event of a late go-around...

Engine produces rated 1279HP achieved by formula
HP = Prop RPM.Torque/5252 (engineering constant)

in this case 1700 x 3950 / 5252 = 1279

If props remain at cruise setting say 1550 we achieve less HP... if I get a comment about the extra noise suffered from bringing the props to 1700 I generally point out that it's nothing compared to the noise of the a/c impacting a catering truck that entered the runway by mistake.

[Chuck Ellsworth]

The PT6 is a turbine, they do not have the same problems that piston engines have due to the simple fact they are turbines.

I was referring to piston engines when I started this thread.