Originally Posted by Sunfish
What is to stop you retracting flap to extend your glide?
Nothing, as long as you adjust your speed (and trim) to correspond with the configuration. If you forget to trim, under the pump the aircraft will move away from the best L/D speed for that configuration, and you will have not achieved your aim.
I think most pilots would be better served by going straight for the carby heat if on short finals at YMMB if the engine splutters and dies, historically carby icing is the real issue, not how much flap one has selected or the size/shape of circuit flown.
Off field, what should have been taught is that first, if you are looking short, is to reduce the distance to touchdown by turning towards the aim point earlier, i.e. making crosswind, downwind, base shorter. Flap selection should be restricted to leave as much variation of control as possible over the angle and rate of descent.
Originally Posted by Sunfish
I've never seen this discussed, let alone demonstrated or taught.
That would surprise me, when doing glide approaches in the circuit, or PFLs in the training area/NAVs, it is a standard consideration given in the briefing. I would find it hard to believe that at no stage this was covered. What you may have had is a recent light bulb moment and actually connected the dots and reinvented the wheel.
Originally Posted by The Green Goblin
First of all, you should not have 'full flap' in a C172 at 500 feet.
Blanket statement like that are not useful.
The CASA standard that is expected to be taught is "turn onto final at about 500FT and select landing flap when rolled out on final", that is straight from their instructor manual. In reality if you turn onto final at 500 ft, and select full flap when rolled out, you will be just below 500 feet, but not by much.
Originally Posted by The Green Goblin
It may be okay at a GAAP (class D) aerodrome where everyone is doing the same thing, if you fly in the real world and do this with an RPT aeroplane up your behind, you could become an accident waiting to happen - especially if you were not making the required radio calls (which has happened to me on occasion).
That would be poor airmanship on the part of the RPT aircraft. Too often I see pilots of light twins like the SF34 think they are the skygods at regional airports. Airmanship also applies to RPT aircraft, and they should fit into the local traffic pattern, not the other way around.
Airmanship and situational awareness is a two way street.
Originally Posted by The Green Goblin
Energy management is a crucial aspect of airmanship which is not taught.
It is, every GFPT holder must be able to do a PFL, glide, and flapless approach.
Originally Posted by The Green Goblin
A well known ex Kununurra CP used to demonstrate a turn back after take-off and expect his boys to be competent at the maneuver ( manoeuvre ).
Turn backs used to be taught around the world, the procedures comes from high performance (i.e. low drag) aircraft, they work in a glider, PC-9 or PC-12, but not in C152 unless you have enough energy to start with. The procedure is not suited to most GA light singles as pilots do not have the data at which height they will have enough energy to return. Once on crosswind, a 90 degree turn towards the runway become far more possible.
A turn back in a C172 would require a 45 degree AoB turn, which places the aircraft at the stall speed at low altitude in an emergency. The altitude loss for a 180 degree turn in "test pilot" conditions is 200-300 ft. A PPL holder being hit with an engine failure, and then a subsequent stall warning would not fair so well.
In a paper presented to the AIAA, 28 pilots with experience levels from 40 hrs to 5000 hrs were put in a simulator and told to expect and emergency at some stage.
They were given a takeoff clearance to climb straight ahead to 3000'. At 500 ft they were given an engine failure, 85% of pilots landed straight ahead, no crashes, of the 15% that attempted a turn back, 2/3 crashed from steep bank/stall.
Then they were repositioned for takeoff, pilots were told to expect engine failure at 500’, and they could handle it any way they wish. 90% of the pilots landed straight ahead, no crashes. Of the 10% that turned back, 50% crashed.
They were then repositioned again for takeoff. Pilots were told to attempt 180 turn upon engine failure, only 43% of them were successful. 85% of failures involved bank exceeding 55 degrees which is a low level stall/spin entry.
It is far safer to land in area that would require smaller angles of bank to maximise the stall buffer. This become even more pronounced in low visibility and at night, and with low experience.
Turn backs in GA aircraft at low altitude in my view are right up there with going past a perfectly good airport if you have a problem to save your boss a few bills, or not closing the second throttle on a light twin when not achieving some climb performance.
Originally Posted by The Green Goblin
Something like a PC12, a turnback after takeoff is a QRH maneuver ( manoeuvre ).
You must have flown a different PC-12 than I have. The RFDS does teach turn back when above a certain altitude, they also teach an IMC cloud break procedure which gets you over the runway at 400ft/Vne if engine out in IMC, similar to what the RAAF do in the PC-9. They are not manufacturers procedures and I would not recommend either to anyone not having been taught them conducting them in anger.
Originally Posted by RadioSaigon
WHY oh why are you even discussing a "stabilised" approach??? It's an inappropriate notion when discussing the average GA airframe -up to & including most twins!!!
Stabilised approaches need to be taught as people without much experience need a consistent picture to hang their hat on. They do not have the experience or judgement to fly a circuit as efficiently say a pilot that has done 1000 hrs of bungles joy flights.
The majority of people I have taught went on to fly other aircraft apart from GA singles. Even in a GA single, conducting an instrument approach requires the aircraft to be stabilised from the FAF/FAP. The earlier this concept is taught, the easier it is to move from the known (VFR) to the unknown (NVFR/IMC) training. Night training should also involve stable consistent approaches.
Originally Posted by ForkTailedDrKiller
What is the problem with overshooting with 40o flap?
Nothing at all, as long as the correct procedure is applied.