5 ms·
Also not a pilot but my understanding is that spins in multiengine aircraft are generally considered extremely dangerous, to the extent that they aren't even sp
by caconym_ 5y ago
Also not a pilot but my understanding is that spins in multiengine aircraft are generally considered extremely dangerous, to the extent that they aren't even spun in testing/certification. From here^[1]:
> No multiengine airplane is approved for spins, and their spin recovery characteristics are generally very poor. It is therefore necessary to practice spin avoidance and maintain a high awareness of situations that can result in an inadvertent spin.
In something like a Caravan this might not be such a big deal (though I don't know about their stall-spin characteristics) but deliberately courting stall-spin in a big twin like a King Air by using asymmetrical thrust so close to stall seems extraordinarily dangerous bordering on reckless, even if you aren't counting the presence of skydivers near the out-of-control aircraft. The fact that it's established practice doesn't mean it's safe; it can just as easily be a "normalization of deviance" sort of thing.
As other commenters have mentioned, I think bringing both engines back to low power or idle, and accepting a moderate sink rate during the jump, would be much safer. That way, even if you do stall, you at least aren't doing it in an asymmetrical thrust condition.
^[1] https://www.flightliteracy.com/stalls-in-multiengine-aircraft/ https://www.flightliteracy.com/stalls-in-multiengine-aircraf...
- lazide 5y agoIf there is a sizable sink rate, or higher speeds, the odds of a jumper hitting the elevator or other parts of the plane are higher. We used to have to watch out even on little Cessna 182s - in the right conditions someone could easily hit it and rip it off, then everyone is in a world of hurt.
- caconym_ 5y agoRegarding higher airspeed, I'm not suggesting that they go any faster—only that they burn altitude to maintain airspeed instead of flying level on asymmetrical thrust. Regarding sink rate, in the absence of a definitive source I don't really buy that a moderate sink rate (again, with the same low airspeed) is going to significantly increase the risk of somebody hitting the tailplane. In the absurd extreme of a vertical dive, I guess a skydiver would probably be outpaced by the aircraft due to their different terminal velocities, but a shallow dive is a very different picture.
- lazide 5y agoIt’s not uncommon to be a foot from the elevator on some models of jump planes - when flying level, and without ‘floating’ out the door like some folks are prone to do. As with many things, ‘it depends’. Most jumpers aren’t going to be happy burning the altitude they just bought with their jump ticket so the pilot can be a little lazier though.
- caconym_ 5y agoMost jumpers probably have no idea how dangerous it is to spin a multiengine aircraft, and anybody who would classify as "lazy" a pilot's avoidance of an asymmetrical thrust condition a hair above stall with a large, draggy mass hanging off the opposite side of the aircraft is, frankly, not really qualified to opine on the subject. Spinning a King Air is, from an aviation safety point of view, unacceptable. Accidents happen, but the point is that great pains must be taken to prevent them from happening again; and if the skydiving community wants to convince the aviation community at large that this procedure is perfectly safe, they really need to show that what happened here was a freak accident rather than a totally predictable one. That will be a tall order, because it was a totally predictable accident. Safety needs to take precedence over convenience. If the King Air can't run skydiving operations safely and conveniently, maybe it should not be used for skydiving operations.
- Aeolun 5y agoI think there are enough skydives that we’d notice if this caused issues regularly?
- caconym_ 5y agoHow many skydives out of twins using this procedure or similar?