Stabilized approach... IFR...flaps????

Possum

Possum

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Question on a stabilized approach, IFR, and the use of flaps and the airspeed. If you are on an ILS approach do you use flaps while on the approach or add them when you reach the DA or have the runway in sight? So, when do you apply the flaps on a stabilized approach? Second, at what airspeed would you fly the stabilized approach in a Cessna 172 while on the glideslope? Finally, while on your IFR check ride and you exceed your stabilized approach airspeed by 10+ knots, is it a bust?
 
Depends a bit on whether precision or non-precision approach.

In any situation the last notch of flap goes in only after I know I can make the runway (assuming I want to make a full flap landing)

First flap normally in at the IF. Gear down on GS intercept non-precision, or just before FAF on a precision approach.
 
I would fly 10 degrees of flaps about 10 or 15 knots below the top of the white arc, and then transition to full flaps during the visual segment below DA if it was a short enough runway to require it. The stabilized approach criteria in the ACS could be read as excluding that technique, however. I’d suggest contacting your examiner to find out whether whatever technique you decide on meets his interpretation.

As far as unsatisfactory performance, Appendix 5 says this (emphasis mine):
• Consistently exceeding tolerances stated in the skill elements of the Task.
• Failure to take prompt corrective action when tolerances are exceeded.
 
Possum said:
Question on a stabilized approach, IFR, and the use of flaps and the airspeed. If you are on an ILS approach do you use flaps while on the approach or add them when you reach the DA or have the runway in sight? So, when do you apply the flaps on a stabilized approach? Second, at what airspeed would you fly the stabilized approach in a Cessna 172 while on the glideslope? Finally, while on your IFR check ride and you exceed your stabilized approach airspeed by 10+ knots, is it a bust?
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In the PA28 I was taught 1 notch and 90 knots just before the FAF, IE, about 1 minute before the FAF. From there, leave that config until you break out and have visual with the runway. I was told not to keep messing with flaps and airspeed while in the clouds on a sensitive ILS approach as it can mess up your LOC/Glideslope

To date, I've come out at minimums (in PA28) and not had an issue getting the last few notches of flaps in and slowing down as needed

In something faster, like the SR22, I do one notch and 110 knots just before the FAF. I have, in this plane, when very stabilized, slowed to 90 and put in the next notch of flaps (2 of 2). Otherwise I'm not sure I'd be able to maintain a stable approach from 200' in the air slowing down and getting the last notch in so close to the ground/runway
 
I teach my students to add 10 degrees and have airspeed of 80 to 90 about a mile prior to FAF.
 
A lot depends on what aircraft you are flying. In a 172 with the 110k 10 degree limit, I'd certainly hang out 10 degrees. On the Navion, if I'm trying to keep my speed up, the flaps MUST stay up (87 knot Vfe).
 
flyingron said:
A lot depends on what aircraft you are flying. In a 172 with the 110k 10 degree limit, I'd certainly hang out 10 degrees. On the Navion, if I'm trying to keep my speed up, the flaps MUST stay up (87 knot Vfe).
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This. In my Mooney, I don’t use flaps until I have runway in sight. Gear doesn’t even go down until faf. Gear and flap speeds are way too slow to do it earlier. Also makes going missed less adventurous.
 
Greatly airplane dependent. No flaps for me, 90 knots on the approach. On breakout, full flaps and decelerate to normal landing speed of 75-80 mph. Otherwise I'm ready for the miss.. I'll never be out of runway with this plane operating this way on an ILS or LPV. YMMV.
 
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In a 172, 1-2 miles before FAF, flaps 10, 90kts is good. Every approach is different but in a perfect world, this is a good baseline. If ATC needs you to go faster and you’re not comfortable just say “unable.” Either they’ll break you off or break the guy behind you off.
 
My CFI has me set the plane up at just about 1/2 dot above GS intercept by dropping gear and adding first flap setting. Then it’s down to DA or MDA or transition to visual. I fly a Comanche 250 so speed is about 90 Knots on final. A bit faster as I reach GS intercept so the gear and flaps slow me down and I get configured to land.


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Cirrus teaches 120kts until 2 miles before faf for non precision, or when GS starts indicating (full diamond) for precision. At this point 50% (first notch) flaps, slow to 100 kts. Maintain 100knts down the gs or during the descent. If you see the runway before you reach 500 agl you can add full flaps, if not, land with 50% flaps. This is for the 22, 22T and 20.
 
There's also the question of whether it makes sense to fly our light pistons as if they were large jets. A 3° approach slope is perfect for a large, clean aircraft — the only struggle is to get rid of the extra airspeed so that you don't overshoot.

For our light pistons, though, a 3° approach slope means dragging our planes in under power, and landing short in the trees if anything goes wrong. There's no choice, really, for a precision IFR approach, but in any other situation, it makes more sense for us to come in at around a 6° approach slope (where we can glide to the runway, just like a big jet can on a 3° slope), to do a gradual roundout in the last 100 ft AGL (instead of staying on a constant slope), and to wait to add most flaps until near the end — those are "unstable approaches" according to recent FAA and Transport Canada training and testing guidelines, but they're safe and natural ways to fly our light piston aircraft (which have less inertia and respond quickly to configuration changes, unlike transport aircraft with heavy wing loading).

tl;dr - not every light-aircraft pilot plans to go on to an airline job, so why make us pretend our Cessnas and Pipers are airliners?
 
flyingron said:
A lot depends on what aircraft you are flying.
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Absolutely. There is no one universal answer. It's a combination of aircraft, IAP, selected approach speed and, ultimately, pilot preference. Pilot A might fly a 172 approach with no flaps until breaking out. Pilot B might always use 10° of flaps. Pilot C might use 10° flaps except when keeping speed up when requested by ATC.

I've flown about 30 different type of singles. There are only 4 (5 if the runway is short) in which I use any approach flaps. Someone else's numbers might be very different.

If I've seen one commonality, it's limiting flap deployment to the first (approach) flap setting until breaking out, to limit missed approach workload.
 
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Possum said:
when do you apply the flaps on a stabilized approach?
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Again, it depends. In all but one of the airplanes where I use flaps, it's part of the "go down" process when crossing the FAF, similar to the "gear down/go down" most retract pilots use. I the other it's before the intercept.
 
When flying a high wing CESSNA with retractable gear, 210’s & Cardinal RG’s, approach the FAF at 90 knots and when the glide slope needle starts to center drop the gear and 10 degrees of flaps simultaneously you will have minimized needed trim and power adjustments. This technique will make it easier to transition to the required descent configuration for the glide slope with minimum pilot workload. I like to be as consistent as possible with all CESSNA airplane approaches and for that reason I always drop 10 degrees of flaps with fixed gear models also when the glide slope centers even though the benefit of balancing out trim adjustments is not there without adding the drag of the gear change. If you think you will start flying high wing retractables at some point in the future I suggest getting in the habit of using this technique. It will make the transition to these higher performance models easier to adapt to.
 
Still in training, a few more flights from checkride.

182
90 kts
2 miles from FAF I was taught Flaps 10

Sometimes I add flaps 20 after acquiring visual, sometimes not.
 
MauleSkinner said:
From what point can a jet glide to the runway on a 3-degree slope?
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Right — I just did the math, and a B-747 would need roughly a 4° glide slope no-wind with its 15:1 glide ratio. But if they're still shedding speed as well while they're coming down (rather than starting at best glide), then I think they'd have a chance at 3° for a few miles with the extra inertial energy.

Our light pistons tend to have around a 10:1 glide ratio and much less inertia, so we really need that 6° glide slope when we can get it, and are using a lot of power to maintain an airliner-style 3° slope (typically about 1,900 rpm clean in my fixed-pitch PA-28).
 
midlifeflyer said:
A question: Are you recommending not following the glideslope/path on an ILS/APV?
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This part of my original post, which you cut out when quoting it, answered your question:
…There's no choice, really, for a precision IFR approach, but in any other situation, it makes more sense for us to come in at around a 6° approach slope…
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David Megginson said:
Right — I just did the math, and a B-747 would need roughly a 4° glide slope no-wind with its 15:1 glide ratio. But if they're still shedding speed as well while they're coming down (rather than starting at best glide), then I think they'd have a chance at 3° for a few miles with the extra inertial energy.
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747s and other jets don’t fly the final portion of the approach clean while shedding energy.
 
David Megginson said:
This part of my original post, which you cut out when quoting it, answered your question:
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I guess that's what confused me since we are talking about instrument approaches.
Yes, I learned the "dive and drive" technique too when I did my instrument training back in the day. But I learned pretty quickly it was unnecessary in all but a very few situations. While you are certainly welcome to I'm not coming in on a 6° slope (900 FPM at a common light single 90 KTS instrument approach speed) through the clouds to the MDA even on a nonprecision approach unless the plate tells me it's extra special. Good example would be the VOR/DME-A at Kremmling, Colorado (20V) where, if you wanted to fly a 3° glidepath to the runway, including a god VDP, you'd have to be at MDA before you crossed the FAF!
upload_2020-10-18_13-18-21.png
 
David Megginson said:
Right — I just did the math, and a B-747 would need roughly a 4° glide slope no-wind with its 15:1 glide ratio. But if they're still shedding speed as well while they're coming down (rather than starting at best glide), then I think they'd have a chance at 3° for a few miles with the extra inertial energy.
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Wow! 15:1 with gear and flaps hanging out? What’s the glide ratio clean at the proper speed?
 
midlifeflyer said:
I guess that's what confused me since we are talking about instrument approaches.
Yes, I learned the "dive and drive" technique too when I did my instrument training back in the day. But I learned pretty quickly it was unnecessary in all but a very few situations. While you are certainly welcome to I'm not coming in on a 6° slope (900 FPM at a common light single 90 KTS instrument approach speed) through the clouds to the MDA even on a nonprecision approach unless the plate tells me it's extra special. Good example would be the VOR/DME-A at Kremmling, Colorado (20V) where, if you wanted to fly a 3° glidepath to the runway, including a god VDP, you'd have to be at MDA before you crossed the FAF!
View attachment 91139
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6° is for the final approach when you're in visual contact with the runway and maybe 500–1,000 ft up. No point doing that at 2,000 or 3,000 ft AGL. A lot of light pistons use that as their enroute cruising altitude when they're VFR.

As I mentioned earlier, my beef is with the new guidance that you have to continue that 3° glide slope right down to the runway, VFR or IFR, or you don't count as "stabilized". That's not a great way to fly a short final in a piston aircraft, in my opinion, and I suspect the motivation was to prevent student pilots who were going to go on to the airlines from developing "bad habits" for their hypothetical future big iron, not actually to make us better light piston pilots.
 
David Megginson said:
That's its clean glide ratio — someone asked how a 747 could glide on a 3° glide slope.
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That someone was referring to your post that implied that a 747 that was actually on a 3-degree glide slope (and therefore configure for the approach) could glide to the runway.
 
gear down....10 deg of flaps....till we see the runway....then we slow below approach speed and add more flaps.
 
David Megginson said:
As I mentioned earlier, my beef is with the new guidance that you have to continue that 3° glide slope right down to the runway, VFR or IFR, or you don't count as "stabilized". That's not a great way to fly a short final in a piston aircraft, in my opinion, and I suspect the motivation was to prevent student pilots who were going to go on to the airlines from developing "bad habits" for their hypothetical future big iron, not actually to make us better light piston pilots.
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What was the old guidance?

What current guidance are you referring to that mandates a 3-degree glide slope when VFR?
 
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David Megginson said:
6° is for the final approach when you're in visual contact with the runway and maybe 500–1,000 ft up. No point doing that at 2,000 or 3,000 ft AGL. A lot of light pistons use that as their enroute cruising altitude when they're VFR.
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I still don't. I fly an approx. 3 degree glide path (that PAPI/VASI thing) on final unless terrain or runway length (or my misjudgment) requires a steeper descent, in which case it's typically 4.5.
 
David Megginson said:
6° is for the final approach when you're in visual contact with the runway and maybe 500–1,000 ft up.
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So are you saying you want the approach to be built so that the last 500’ requires a 6°GS, the entire approach to be 6°, or that you just want the ability to establish a 6° GS for the final portion of the approach? I’m not quite following what you think should be changed.
 
Boone said:
So are you saying you want the approach to be built so that the last 500’ requires a 6°GS, the entire approach to be 6°, or that you just want the ability to establish a 6° GS for the final portion of the approach? I’m not quite following what you think should be changed.
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I suspect he wants more approaches on an instrument checkride...the ones that are there to evaluate a pilot’s ability to fly to minimums, and additional approaches to evaluate the pilot’s ability to fly approaches in various levels of VMC.
 
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midlifeflyer said:
I guess that's what confused me since we are talking about instrument approaches.
Yes, I learned the "dive and drive" technique too when I did my instrument training back in the day. But I learned pretty quickly it was unnecessary in all but a very few situations. While you are certainly welcome to I'm not coming in on a 6° slope (900 FPM at a common light single 90 KTS instrument approach speed) through the clouds to the MDA even on a nonprecision approach unless the plate tells me it's extra special. Good example would be the VOR/DME-A at Kremmling, Colorado (20V) where, if you wanted to fly a 3° glidepath to the runway, including a god VDP, you'd have to be at MDA before you crossed the FAF!
View attachment 91139
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Speaking of excessively high DAs, take a looksee at KMSO ILS Y RWY 12... Have not seen a lot of ILS approaches with no LOC minimums, let alone better-than-basic-VFR weather requirements.

Screenshot_20200905-080529_Pilot.jpg
 
smv said:
Speaking of excessively high DAs, take a looksee at KMSO ILS Y RWY 12... Have not seen a lot of ILS approaches with no LOC minimums, let alone better-than-basic-VFR weather requirements.

View attachment 91155
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I believe the other ILS to 12 is lower, but requires a higher-than-standard missed approach climb gradient.
 
MauleSkinner said:
I believe the other ILS to 12 is lower, but requires a higher-than-standard missed approach climb gradient.
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Indeed. ILS Z is a "normal" ILS (still sans LOC minimums) down to 211' AGL but requires 410' per NM to 9800' on the missed... Lots of pointy rocks in that area.
 
in my mighty 150hp c172L I don't put the flaps in until I break out. my descent is 90kts no flaps. the second I pull power to land I am with in flap speed and she slows right down. I am new to the IFR game and thats the only training I have received. Maybe after I punch my ticket I'll try flaps at the FAF on some practice approaches... until then I will do what feels comfortable and is safe.
 
1SGBrokePilot said:
in my mighty 150hp c172L I don't put the flaps in until I break out. my descent is 90kts no flaps. the second I pull power to land I am with in flap speed and she slows right down. I am new to the IFR game and thats the only training I have received. Maybe after I punch my ticket I'll try flaps at the FAF on some practice approaches... until then I will do what feels comfortable and is safe.
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Do it the way you learned it. When you move to faster, get a thorough check out.
 
A lot of variables. If doing a true approach to minimums, I don’t see how one wants to do any configuration changes at a few 100’ AGL. The deal is to see the approach environment & land, not reach for a flap handle. I’d be configuring back a ways.

Also, much of the time one doesn’t need ‘full flaps’, I’ll often take a little less.
 
1SGBrokePilot said:
in my mighty 150hp c172L I don't put the flaps in until I break out. my descent is 90kts no flaps. the second I pull power to land I am with in flap speed and she slows right down. I am new to the IFR game and thats the only training I have received. Maybe after I punch my ticket I'll try flaps at the FAF on some practice approaches... until then I will do what feels comfortable and is safe.
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In a 172, if that's how you learned it, stick with it. It works and really, the one experience most report not running into later is being asked to keep speed up. That's when some pilots who learned flapped approaches in a 172 can have a problem if they haven't done it withou them. (The one time I flew an approach at 120 KIAS in a 172 was a lot of fun)
 
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