I am planning a (first) skydive, a tandem jump with an instructor. However, I have not picked which school I will use yet.
I am convinced about the safety of the jump itself, but cannot find reliable data on accidents that have occurred during the actual flight.
How safe are aircraft that are used for skydives? What are the statistics compared to commercial aviation?
You didn't mention any particular country, but for the US I found an NTSB report called On the Safety of Parachute Jump Operations. It's from 2008 so some of it may be dated, but it says that no reliable data exist (emphasis mine):
According to USPA safety records, from 1992 through 2007, about 30 parachutists per year were killed in jumping mishaps. Safety Board accident data show that, for the same time frame, about five parachutist fatalities per year resulted from accidents involving parachute operations aircraft. Direct comparisons of associated risk are difficult to calculate due to the likelihood of multiple parachutists being carried on each flight and a lack of departure data for parachute jump operations. The Safety Board notes that the FAA does not have data on the number of parachute jump operators or the number and type of aircraft used in parachute jump operations in the U.S. The absence of these data precludes any calculations of safety statistics for parachute jump operations, including accidents rates.
Based on that information, you have 5 fatalities per year related to aircraft, and 25 that are not. So the aircraft should be the least of your worries.
Here are some key points from the rest of the report:
a segment of U.S. general aviation operations, which, according to data compiled by the United States Parachute Association (USPA),[1]transports parachutists on 2.16 to 3 million jumps annually.[2]
[...]
Since 1980, 32 accidents involving parachute operations aircraft have killed 172 people; [6]most of whom were parachutists.
[...]
The investigation identified maintenance discrepancies on the airplane and deficiencies with the pilot's performance of emergency procedures; these issues prompted the Safety Board to examine accident reports for parachute operations to determine if such safety issues may be widespread. The results, discussed in this investigation report, show that these issues were present in many accidents
[...]
The Safety Board's review of parachute operations accidents since 1980 identified the following recurring safety issues:
- Inadequate aircraft inspection and maintenance;
- Pilot performance deficiencies in basic airmanship tasks, such as preflight inspections, weight and balance calculations, and emergency and recovery procedures; and
- Inadequate FAA oversight and direct surveillance of parachute operations.
Anecdotally, skydiving is indeed associated with poor maintenance and hiring low-time commercial pilots. It's one of the few commercial activities that doesn't require an air operator certificate (see 14 CFR 119.1(e)(6)) so it can operate under part 91, without the more stringent rules and requirements of part 135. That also means there are no minimum hours required for the pilot as long as he holds a commercial certificate, and it's a very sought-after job for commercial pilots who want to build hours without instructing.
However, anecdotes tell you nothing useful at all about the overall safety of the industry, or about the safety of an individual skydiving operation. Some research is good and I think you can look for some common sense things that you might look for in any business: professional location, good customer service, good online presence, good reviews etc. But trying to quantify the risk in a meaningful way is extremely difficult, and you still have to balance it against the reward and against the risks of whatever else you would do that day instead of skydiving.
I'm an ex jumper and I'd say the two major risks in a skydiving airplane ride are engine failure on take off or while too low to bail out, and a canopy deployment out an open door while in flight.
If you're in a piston engine Cessna 206 and the engine quits at 200 feet and there isn't lots of runway still out front, it's gonna hurt. If you're in a piston twin like a Seneca and an engine quits and you're heavily loaded, usually the good engine succeeds only in taking you directly to the scene of the crash (piston twins at gross weight are so marginal that it's safer to treat them as a single engine with a really flat glide).
Single engine turbine like a Caravan, much better because the engine is way more reliable than something like a 6 cylinder IO-540. If it's a turbine twin machine like a King Air or Twin Otter, with turbine reliability and the single engine performance is adequate, this would be the safest.
Really though, the same applies to any airplane ride, but in a jump plane you're more exposed by not being strapped into a seat.
The other risk, canopy deployments, is mitigated by having a jump door and the deployment risk is only in the couple minutes at altitude where you're in the open door. If no jump door, it takes intense vigilance by the jump master to prevent someone's pilot chute from coming loose on the entire ride up.
So if I had to choose between a skydiving center where I have to ride up in a single engine piston like a 206, or one that used a Caravan, I'd go with the Caravan. And if another one used a Twin Otter, I'd go with that one. All other factors being equal of course. And I wouldn't go in one without a jump door (although I doubt anybody flies with without them these days).
I think the way you ask the question is wrong and the comments are here on spot. However, I get your concerns; after all it would be better to die due to a malfunctioning parachute rather than a plane crash, right?
To answer your question first we need to know the type of aircraft. I will take two examples here. (if you need any other type you can check it on aviation-safety.net)
Hull-losses: 222
Hull-loss accidents: 211 with a total of 446 fatalities
Criminal occurrences (hull-losses, excl. hijackings): 0 with a total of 0 fatalities
Hijackings: 6 with a total of 1 fatalities
Survival rate: 28.8% of all occupants survived fatal accidents
Stats for Beechcraft King Air:
Hull-losses: 218
Hull-loss accidents: 188 with a total of 503 fatalities
Criminal occurrences (hull-losses, excl. hijackings): 5 with a total of 2 fatalities
Hijackings: 1 with a total of 0 fatalities
Survival rate: 8.7% of all occupants survived fatal accidents
