C172L flap switch
I agree, but it's interesting just how many flight schools won't allow use of 40 flaps in C150s and C172s as if there is something dangerous about them. Similarly some schools have a prohibition on sideslipping with full flaps, for (probably) equally spurious reasons.
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In my opinion it falls under the same category as encouraging 'flat' approaches because it's 'too hard' to land off a steeper approach. If you're going to allow the required handling skills to degrade to the point where that's an issue, then something's going very wrong.
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I was always led to believe (bear in mind I'm a beginner) that anything over 20 degrees was just extra drag and added little if anything to the lift coefficient. So if you're using a long runway (like me) there's little point in dragging it in with 40 degrees of flap and then taxiing 4,000 ft to the turn off. However today I flew to a smallish grass strip and used 40 degrees. Because the circumstances warranted it.
I do find personally that I seem to land better with only 20 degrees of flap. Don't know why. My landings with 40 degrees are perfectly fine, I just find there's a better feel with 20 degrees. My 40 degree ones tend to be arrivals, not clonking on but a nice firm 'yes the tires are on the grass' which is what you want on a short strip whereas my 20 degree ones are the sweetest brushing of Dunlop on mother concrete. Allowance for artistic license.
But then no doubt someone will be along to tell me that my 40 degree landings should be like that too. Reminds me of those flying videos you see on YouTube, you watch what seems to be a perfectly fine approach and landing and nod in approval. Then you read the comments and someone will always be along to say 'You were 6 inches to the left of the centerline and came in 1 knot too fast plus your flare was started 11 microseconds too late.'
I mean I actually bounced about 2 inches landing on my grass strip today. Back to the drawing board for me then.
I do find personally that I seem to land better with only 20 degrees of flap. Don't know why. My landings with 40 degrees are perfectly fine, I just find there's a better feel with 20 degrees. My 40 degree ones tend to be arrivals, not clonking on but a nice firm 'yes the tires are on the grass' which is what you want on a short strip whereas my 20 degree ones are the sweetest brushing of Dunlop on mother concrete. Allowance for artistic license.
But then no doubt someone will be along to tell me that my 40 degree landings should be like that too. Reminds me of those flying videos you see on YouTube, you watch what seems to be a perfectly fine approach and landing and nod in approval. Then you read the comments and someone will always be along to say 'You were 6 inches to the left of the centerline and came in 1 knot too fast plus your flare was started 11 microseconds too late.'
I mean I actually bounced about 2 inches landing on my grass strip today. Back to the drawing board for me then.
Last edited by thing; 31st Aug 2011 at 17:51.
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In my opinion it falls under the same category as encouraging 'flat' approaches because it's 'too hard' to land off a steeper approach. If you're going to allow the required handling skills to degrade to the point where that's an issue, then something's going very wrong.
a) be able to control your a/c in all configurations
b) use the above skill to adjust to the circumstances
The a) above obviously includes 40deg flap landings!
Re the sideslipping prohibition - some Cessnas are placarded as such.
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At the risk of being beset upon by a throng of angry instructors, it has been said on PPRuNe, and I am tending to agree, that the training organizations are building upon a "heritage of inexperience". When the capabilities designed into the aircraft, are being supressed and under utilized during training, those who come to conduct training (new instructors) will do so based upon that diluted training, which they themselves received. This will continue that heritage to the generations of pilot to come.
I am frequently amazed to experience what training is comprized of now, relative to what I was formally taught 35 years ago. Flap use and sideslipping are certainly two of these things. Pilots seem to be scared of flap use, for no reason I can see. If flying with fully extended flaps requires more skill, then learn and practice that skill! I have certainly demonstrated full flap techinques to newer pilots, sometimes coupled with STOL kits, and have literally left them speachless. These were not dramatic demonstrations, those newer pilots were just unfamiliar with what to expect. I have had air traffic controllers ask if the plane I just landed had a STOL kit, and often I would reply "no", just the regular version. They obviously did not see them landed short very often.
Soft field landing techniques tend toward less wear and tear on the plane, lower speeds (= less risk), and require greater flap settings. Short field landings are similarly the latter two, though can be a bit rougher on the plane sometimes. I cannot think of a good reason that most landings a pilot would do, where he/she had the option of type of landing, would not be a practice soft or short field technique. Perhaps it is just the exmple which has been set for them during training.
Not "Prohibited", just "Avoid". In the certification world there is a difference. If "prohibited" were required becasue of the way the plane handled in that configuration, it would not be certified at all. It is not possible to "prohibit" away a certification requirement, and sideslips in all configurations are a certification requirement.
Thing,
The 40 flap landing in a Cessna will result in a shorter length of time in the flare, before either you settle to the ground (gently, or "arrival"), or have to add some power. Next time you have lots of runway, and you are comfortale with full flaps for the conditions, try easing some power back in as you begin your flare. It will prolong the flare a little, and soften your contact with the ground. Once your main wheels touch, hold the attitude so the nose wheel stays off as you close the throttle. Keep holding the nosewheel off for the whole rollout. You'll still have a gentle, and pleasing landing, and it will be happily short too!
I am frequently amazed to experience what training is comprized of now, relative to what I was formally taught 35 years ago. Flap use and sideslipping are certainly two of these things. Pilots seem to be scared of flap use, for no reason I can see. If flying with fully extended flaps requires more skill, then learn and practice that skill! I have certainly demonstrated full flap techinques to newer pilots, sometimes coupled with STOL kits, and have literally left them speachless. These were not dramatic demonstrations, those newer pilots were just unfamiliar with what to expect. I have had air traffic controllers ask if the plane I just landed had a STOL kit, and often I would reply "no", just the regular version. They obviously did not see them landed short very often.
Soft field landing techniques tend toward less wear and tear on the plane, lower speeds (= less risk), and require greater flap settings. Short field landings are similarly the latter two, though can be a bit rougher on the plane sometimes. I cannot think of a good reason that most landings a pilot would do, where he/she had the option of type of landing, would not be a practice soft or short field technique. Perhaps it is just the exmple which has been set for them during training.
Re the sideslipping prohibition - some Cessnas are placarded as such
Thing,
The 40 flap landing in a Cessna will result in a shorter length of time in the flare, before either you settle to the ground (gently, or "arrival"), or have to add some power. Next time you have lots of runway, and you are comfortale with full flaps for the conditions, try easing some power back in as you begin your flare. It will prolong the flare a little, and soften your contact with the ground. Once your main wheels touch, hold the attitude so the nose wheel stays off as you close the throttle. Keep holding the nosewheel off for the whole rollout. You'll still have a gentle, and pleasing landing, and it will be happily short too!
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OK PilotDAR, I will give you my theory on why some pilots find a 40 degree flap landing in a C172 to be "unnatural" - it's all about the PAPI and ILS.
I routinely land a C172 with 40 degrees of flap, and the resulting approach angle (even if we are carrying some power) is MUCH steeper than 3 degrees. If you are landing at a small grass strip, that is both good practice, and great fun. But, on a large runway with a PAPI at the side, you have to agree that the glideslope indications - and the "feel" of looking steeply at the first hundred feet of another two miles of runway is somehow contra indicated. So, people who learn to fly on those runways are in the habit of dragging the C172 down a long 3 degree glideslope with 20 degrees of flap and a lot of power.
Tha's my theory anyway....
I routinely land a C172 with 40 degrees of flap, and the resulting approach angle (even if we are carrying some power) is MUCH steeper than 3 degrees. If you are landing at a small grass strip, that is both good practice, and great fun. But, on a large runway with a PAPI at the side, you have to agree that the glideslope indications - and the "feel" of looking steeply at the first hundred feet of another two miles of runway is somehow contra indicated. So, people who learn to fly on those runways are in the habit of dragging the C172 down a long 3 degree glideslope with 20 degrees of flap and a lot of power.
Tha's my theory anyway....
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Pull what - I don't believe it. However, I've been told many times that power off approaches are not a good idea because the steep angle makes the flare difficult to judge. Personally I consider that absolute rubbish, but there we go..
I'm very much in agreement with PilotDAR wrt training, and I think CJ driver has a point about 3 degree glide slopes - but I can't for the life of me see why you need to fly a 3 degree slope in a 172, nor, if you must, why you can't wind the rest of the flap out somewhat later on final.
As for long runways, one can adjust the aim/touchdown point to finish up somewhere near a turnoff. Probably another howling at offence (runway behind you being useless and all that)
I'm very much in agreement with PilotDAR wrt training, and I think CJ driver has a point about 3 degree glide slopes - but I can't for the life of me see why you need to fly a 3 degree slope in a 172, nor, if you must, why you can't wind the rest of the flap out somewhat later on final.
As for long runways, one can adjust the aim/touchdown point to finish up somewhere near a turnoff. Probably another howling at offence (runway behind you being useless and all that)
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Not at all. I fly from a military airfield and our 'threshold' is the RHAG. Otherwise they have to put the traffic lights on red for the major road that runs past the real threshold. However there is still 590 metres of runway from one end and 810 from the other until the turn off. More than enough for a 20 degree flap landing and no brakes.
I can't see what the argument is here, 20 degrees is fine for the runway I land on most of the time. 40 degrees is fine for grass strips etc. Surely you use your own judgement. I'm lucky that the instructors at my club are vastly experienced, some ex CFS instructors, and teach you not to fly by rote but to fly to the conditions.
Edit: DAR being as you are one of the people whose opinions I respect I'll give that a go next time around. Thanks for the tip. I will also add that I do like to keep my skills up regarding flapless, short field etc even on the 9000 foot or so I have to play with. I must be the odd one out in that I actually enjoy doing the variations of circuit, especially glide ccts. As a glider jock I feel it beholden to me to be able to plonk a spamcan down withing 100 ft of my chosen touchdown point.
I can't see what the argument is here, 20 degrees is fine for the runway I land on most of the time. 40 degrees is fine for grass strips etc. Surely you use your own judgement. I'm lucky that the instructors at my club are vastly experienced, some ex CFS instructors, and teach you not to fly by rote but to fly to the conditions.
Edit: DAR being as you are one of the people whose opinions I respect I'll give that a go next time around. Thanks for the tip. I will also add that I do like to keep my skills up regarding flapless, short field etc even on the 9000 foot or so I have to play with. I must be the odd one out in that I actually enjoy doing the variations of circuit, especially glide ccts. As a glider jock I feel it beholden to me to be able to plonk a spamcan down withing 100 ft of my chosen touchdown point.
Last edited by thing; 31st Aug 2011 at 22:50.
My opinion is along the lines of DAR's. Power off approaches must be routinely practiced to prepare you for the day that you have to do one for real. By limiting your experience you limit your options. We are fortunate enough to fly a 172 which is quite forgiving and has such a large flight envelope you'll surprise yourself at what you can get it to do once you know how. Once you fly other types you'll appreciate this even more.
