Thanks, had never heard of that one.
Stabilised approaches are a massive thing in the airline world. This tends to mean on track, on profile, on speed and in the correct configuration by a specific point, this may be 500ft, 1000ft or whatever else the AOC holder decides. One could quite readily lose ones job for ‘busting’ this rule and continuing to land when not fully ‘stable’ at the required point (in theory if you recognised you messed up and went around then this is not a problem). As such this is the way that many commercial schools teach, which is basically to be right back at final approach speed quite early on. This isn’t even a bad idea when completing a manual flown IFR approach down to 200’, as changing the speed and/or configuration could upset the approach.
It becomes more of an issue when operating light aircraft into generous strips, particularly in pleasant weather. I imagine the vast majority of GA aircraft fly a 3 degree approach with power on, so there is no reason (type dependant) why you cannot fly a large portion of the approach at cruise speed or something higher than approach speed and then slow down closer in, but as long as this would be a ‘bad habit’ in the commercial world, schools that have students aspiring to commerical roles will not want to teach this bad habit, which means your C152 joining a 10 mile final at 3000’ is taught to do so at ~60kts or whatever Vapp is.
I find this to be much less of a problem in flying clubs who do no commercial training, and are happy to teach common sense and airmanship, appropriate to the situation.
This seems plausible, but it seems a bit of a shame that potentially ppl intruction from the “commercial stepping stone” focused outfit will be poorer than a normal GA flying school.
However having seen some airline pilots flying light GA I could find reasons to agree.
It is a shame, but there is a a thought process, the validty of which I can not confirm, that suggests if School ABC consistently spits out fresh CPLs who fly ‘against the grain’, then ‘the airlines’ will be less likely to hire from them in future, which in turn puts prospective students off, which reduces revenue.
Aside from PPL syllabus, I find it was worth getting some flying with 6kh crop duster in Stearman and 10kh airline captain in DA40, the first one covered ASI and asked for “stable approach”, the latter wanted ASI nailed at 81kts as per POH for weight as asked for “stable approach”, as far as I am concerned the two approach & landing were identical, so maybe this concept of “stable approach” only matters for aircrafts with huge inertia and low maneouvrability?
For VFR, you can fly by relying only on the picture, or even do what you wish: when I get bored and no one around, I come a bit higher and fly the whole approach with stick only going faster/slower around it’s low drag speed depending if I am high/low on slope, I still need to glance at ASI to do this but I really have no specific value in my mind as low as 60kts and as high as 100kts initially then freeze it near 70kts at the end
For IFR, I try to stick to airline style of flying faster and on glide path, after an ILS runway has a legal length minima of 5000ft, sometimes long enough to land with VNE if you wish
Now where people get it wrong is when they fly “VFR style in IFR envirement” (neddles, bank, speed are all over the place) or “IFR style in VFR envirenemnt” (clocking 100kts and doing rate 1 turns while trying to put it in 1000ft grass runway)
Pirho wrote:
Stabilised approaches are a massive thing in the airline world. This tends to mean on track, on profile, on speed and in the correct configuration by a specific point
I find that I can fly a very pleasing stabilized approach to a precise landing. The altitude loss from the end of downwind will be stable to the beginning of the flare, the rate of heading change through 180 degrees will be stable from downwind to short final will be be stable, and the rate of speed reduction will be stable from downwind to short final will be stable. The altitude, heading and speed will constantly be changing throughout the approach – but it will be stable. On short final, I will be flying at the appropriate approach speed, configured, with landing flap extended.
As for airspeed indication, it’s really nice to have for reference. I was wishing for it through six flights with my flying boat. Five of those flights were to see if the inspection and repair of the pitot system had worked (for four of them, it had not). Would you believe that a small leak in the diaphragm of the MT Propeller interlock pressure switch constituted the pitot system leak! Not where I’d have thought to look first! I would expect a pilot with a few hours on type recently to be able to fly an approach between 1.3 Vs, and 1.5 Vs without a working airspeed indicator.
Pirho wrote:
I imagine the vast majority of GA aircraft fly a 3 degree approach with power on, so there is no reason (type dependant)
“type dependent” is the key here: You need to know your ride. In my Malibu it is no problem at all (in good weather) to fly 160 indicated on the ILS until 3 miles final. Lowering gear feels like pulling a chute and it’s no issue to reduce the speed to final approach speed within 2 miles.
If you try this with an SR22 even a space shuttle type of runway might not be long enough to get it below flying speed.
For me the key is the weather: In plenty VMC I don’t care too much about stabilized approach and it’s fine to be stabilized (on slope, on path, on speed, on configuration) at one mile. In IMC I aim to be stabilized at least 5 miles out
Peter wrote:
They are telling someone with a C152 to fly the whole final leg at, say, 65kt.A couple of problems with this. First, the serious one that you will be turning base to final at 65kt and it’s a good way to stall and spin.
I don’t have a C152 POH handy, but according to lionel Vref would be about 55 kt which sounds reasonable. In that case even with a 45° bank 65 kt in the base turn would give the same stall margin (30%) as flying the final at 55 kt. Clearly, with a TB20 or even a C172 it would be a different story.
Ibra wrote:
maybe this concept of “stable approach” only matters for aircrafts with huge inertia and low maneouvrability?
I believe that is the case, yes. Particularly with turbojet/fan engine aircraft as such engines have a noticeable lag on applying power. But also since such aircraft virtually always land according to IFR and for instrument approaches I believe stabilised approaches make sense even with low inertia aircraft.
If it did matter for light aircraft VFR, we would see any number of landing accidents.
Pirho wrote:
I imagine the vast majority of GA aircraft fly a 3 degree approach with power on,
You would be imagining incorrectly then…. Why would you EVER drag in a 3deg approach VFR?
I cant remember the last time I flew anything resembling a 3 deg approach.
Regards, SD..
