Interesting to read that Heathrow is trialling aircraft selecting gear down much later in the approach because of the significant improvement in noise pollution.
So when do you select gear and why?
AC Type: Piper Arrow
On an instrument approach, I usually drop the gear at 3-4 miles, i.e. not at the FAF / glideslope intercept, but somewhat later.
On a VFR approach I drop the gear at the mid or end of downwind point. The tricky ones are direct or semi direct approaches, where, there being no such thing as a mid-downwind point, the risk of forgetting the gear is higher. To solve this, I try to figure out an “equivalent” downwind leg distance, i.e. usually when on a 2-3 mile base or final.
However, regarding noise, the time of gear down in SEPs is not a huge factor in my opinion (sure, with the gear down you need more power…), but what is important is when you select the prop full forward. I usually do that on very short final (essentially over the fence). Before that, I actually pull back on the prop lever (at least when the approach is over a noise sensitive area) to give me something like 2100 RPM only.
Unfortunately, I see very few people doing this. Many just select full RPM way early in the approach and then come in (depending on how steep the approach is) at close to redline RPM…
boscomantico wrote:
Many just select full RPM way early in the approach and then come in (depending on how steep the approach is) at close to redline RPM…
That was indeed what I was taught when first using aircraft with constant-speed prop (1986)…
What do you do on an instrument approach? Wouldn’t you want to have the prop fully forward before the DA, which would mean actually moving the lever even earlier (before the FAF?) to avoid destabilising the approach?
I lower the gear on downwind at the latest or on an IFR approach before commencing final descent. I tell this to my students as well but I also tell them that it is better to lower the gear when you are thinking about it before entering the traffic pattern. It is doesn’t really matter if you fly with it out as you are approaching an airfield.
I push the prop to fully forward on my final check. I guess it does not have anything to do with speed but where I got my license we used to say that you can select prop fully forward when you are below 100 kts, this was in C172RG and same goes for PA28 Arrow. This works pretty good but of course the important thing is to have a low manifold pressure to avoid the extra noise. I often refer to the blue one as the “noise-setting” rather than the RPM setting. ;)
I lower the gear on GS intercept as It gives me the correct decent rate without touching anything else.
Prop full forward when crossing the fence both due to noise and because the brake effect will limit the Mooney float.
Whenever i fly RG, not often anymore, i do the gear and flaps at GS intercept, or turning final VFR. I leave the prop where it is to avoid too much noise and i usually forwarded it with the mixture at the time of “Final Check”: LG down, three greens, mixture, prop, landing light on. If i HAD an RG i’d probably leave the prop alone until i need it for a go-around.
VFR – downwind (when flying a proper pattern)
IFR – before FAF. Perhaps too early for someone but I prefere that.
and agree with prop statement above to limit noise. there is not reason to advance prop control 10 mins before landing, there is a lot of noise sensitive areas.
boscomantico wrote:
AC Type: Piper Arrow
…
However, regarding noise, the time of gear down in SEPs is not a huge factor in my opinion (sure, with the gear down you need more power…),
Well, in the case of an Arrow, they make a very distinctive whistling noise with the wheels down :-)
In the ST10 (in most aspects comparable to a PA28R) I use the following flow under IFR:
LOC moving / established on FAT = flaps 1
GS moving / before starting final descent = gear down
400 ft above minimums = flaps 2, prop full forward
Under VFR, it’s roughly the same with flaps 2 (quite a lot of drag) timed as necessary.
On short final, I always do a final check (gear down green light, mixture, prop).
What do you do on an instrument approach? Wouldn’t you want to have the prop fully forward before the DA, which would mean actually moving the lever even earlier (before the FAF?) to avoid destabilising the approach?
Yes and no. I agree in that on an IAP, it should be advanced before reaching the minimums.
But I will not do that at or before the FAF. Doing it during the approach (say at the 1000-foot point), does not destabilize anything for me.
