There are accelerate stop charts in the PA31 POH.
One I prepared for one of our aircraft – T7-NAV Accelerate Stop
Piper publishes ASDA (perhaps not for the Apache), Cessna and also Beechcraft.
Beechtalk has a topic on ASDA comparison between the 58P and 601P, so one of your types published this chart.
Curiosity compels me: Exactly which twins are you guys flying where there even is a balanced/start/stop field length published in POH? None of the ones I’ve ever owned have had that…
Fuji_Abound wrote:
I’d fly faster if the flight manual presented such a procedure.Please can you expand?
I like the idea of carrying extra speed after takeoff, it’s stored energy in case of an engine failure. I do it as appropriate in singles whenever I can. However, in the case of a twin, with gear and flaps down, or in transit, and a prop yet to be feathered, you’re carrying extra drag. As I said, drag increases as a square of the speed, so if you’re going faster than you need to be, you’re carrying that much extra drag you don’t need to be. I was trained to fly twins at the book speeds, unless there is a reference to “X speed. or faster” in the flight manual. Some flight manuals do provide faster climb speeds than Vy, and if that’s appropriate to the operating, great! Otherwise, “making up” new speeds or procedures can introduce unintended consequences.
Some operations tolerate risks beyond those we would normally allow (military operations as an example). I was trained in the Twin Otter to fly minimum speed, 30 degree flap takeoffs. It will do it, but if an engine fails, you’ll be lucky to even get back to the ground under control, from high ground effect, much less if you climbed away at such slow speeds. That maneuver is in the “STOL” operations description, but not within the civil flight manual. A DHC test pilot trained me, just ‘cause he used to demonstrate the aircraft that way. It’s so technique sensitive that it has little value compared to risk in civil operations. As the Twin Otter, and a few other turbines I have flown, have auto feather, that changes things a little, as the time spent with a failed engine at Vyse while the prop is not yet feathered will be brief.
I don’t have a multi rating, is doing complicated stuff while on MEP failures that dead easy?
I think accelerating fast and shallow climb is the simple upfront “cash option” (crash ahead or don’t fly if you can’t afford), if you can’t pay upfront you will have to pay one day using the complex “debt collection” with load of “interests” (collection of body after stall/spin), my feeling this work for everything one can fly: zero engine, one engine, two engines, full/partial power…
My apologies I should have omitted the agl after the 1000 ft for the water tower.
The point I was trying to make is the thinking behind your pre take off briefing can be different for each airport or even each runway. @Pilot_DAR suggested waiting for conditions to change such as perhaps being able to use the reciprocal rwy, that would work as there are no obstacles at the end of the rwy. One could accept the risk that you are unlikely to have an engine failure at the worst possible moment. You might improve your chances by taking off flapless and having decreased drag in the event of an EFATO. I am not sure that adding speed to your Vr would serve any useful purpose unless the POH quotes Vmc as higher than your normal Vr.I am also not sure why you would stall or need thinking time if you have properly briefed yourself. Whether I am in a twin or a single if the engine fails immediately after Vr and before wheels up (in a twin) I close throttles nose down and put the aircraft back on the ground and stop, praying that I don’t hit anything in the process. Its automatic and is drilled into my brain for the aircraft I fly.
Also as suggested I would as part of my brief at Sarlat have calculated a point on the rwy where I should be at a certain speed which if not achieved would be an immediate abort.
That is a very big water tower
It would have to be, in the Netherlands.
yep know that, thus the wording energy/performance point of view, not safety. It does not give room to much of a startle effect either even above Vmca. The point was that carry excess speed on the climb out will cost performance. Seeing the OP data it looked that it was within the envelope for a normal take off but a bit tight.
For some MEPs Vx is below Vmc/Vtoss.
mcrdriver wrote:
From an energy point of view accelerating past Vx until clear of obstacles is a waste
Actually climbing at Vy minimizes energy but evn that energy gain (vs climb at Vx) is worthless as it will only translate to 3 extra seconds of flying in the case of total engine failure bellow 1000ft, depending how “sharp pilot population” we are talking about that does not give much flying or options neither
IMO, if you get an total/partial engine failure at Vx on lift off say bellow 200ft you will stall irrespective of what you fly (e.g. Gliders, SEP, MEP…) or how you would manipulate controls as you don’t have any energy to accelerate or flare (with stress that means +/-10kts on ASI and +/-20 degres on bank angles), so better accelerate to whatever V you think appropriate for your aircraft in the next show (e.g. Vs0, Vms, Vg, Vmca…)
