Originally posted by Chairboy
One theory I had about the Cirrus crashes relates to slow flight. Here's my assumptions:
1. Cirrus states that a spin is to be recovered via CAPS.
2. Spins are hard to start, but happen primarily in slow flight.
3. Use of CAPS essentially destroys the aircraft.
With this in mind, I figure that:
Cirrus pilots are much less likely than other pilots to spend time in slow flight because #2 and they are trained that a spin will result in #3, the plane potentially being written off. Less slow flight, fewer stalls, less familiarity with that part of the performance envelope and can't respond as ably when crap goes down.
If any of those assumptions are wrong, let me know. It's just a theory I've been playing with to try and figure this out. It's a fine aircraft, just some bad accident figures.
1. It states the Approved method is via CAPS. Consider that 90% of the stall spin accidents happen in the traffic pattern at less then 1000 feet - its kind of a moot point at that altitude - normal recovery or parachute.
With choice #2 you might have a chance - choice #1 ain't gonna happen.
The parachute was a core element of the airplane based on Alan K's mid air life saving experience in an ultralight.
The parachute was there before any wings were designed, any elevator travel limits considered etc.
The requirements to PROVE spin recovery are very expensive and Cirrus simply made an argument to the FAA that the presence of a parachute was equal or superior to proving spin recovery so the expensive testing was not required.
I understand that the aircraft was indeed spun by test pilots and it recovered normally and within certification limits, otherwise it would not have been certified under the Normal category.
2. You really gotta **** up to spin the thing. Any plane will spin if you give it enough yaw. Hell a snap roll is essentially a spin in the horizontal plane. Simply, you either gotta get distracted from what you are doing (such as with the guy having his door fly open while he's in slow flight), or really force the plane to do something it does not want to do. I mean, i've flown Extra 300's with Ramzey and if you sneeze your looking at the world from another perspective. And a lot of GA planes - I'd venture most certified since the 50s are going to give you a lot of cues ahead of time before that plane gets away from you.
Lets take the wing design with the cuffs on the outboard leading edge having a different airfoil - so when the inside of the wing is stalled you still have roll control through the stall because the outside of the wing is still not stalled. Now you keep ****ing with it and go over that edge and you are out of coordinated flight - do something stupid like kick in full rudder at high AOA and zero airspeed - you'll find out quickly the timing wasn't right for that.
3. Not necessarily - but thats why you have insurance. Your not interested in salvaging the plane when you think you are going to die. Although, there have been a few that were rebuild after landing in trees or soft terrain. Mostly what you endup replacing are the landing gear and probably the main spar since it would absorb a majority of the impact energy.
The thing about Statistics Chair - the 172 has been around 50 years and through about 15 variants. So your stats pool isn't really pure since they are some franking boxes still in service.
