Wowser! That is certainly concerning.fatsportpilot wrote:Also things like this https://www.aviation.govt.nz/assets/Upl ... ations.pdf
The website states that they have 105 "saves" since they started back in 1984 (36 years ago), or just under 3 "saves" per year. That's good, but there is absolutely no way to know how many of those "saves" might have survived, with or without minor injuries, had they NOT had the chute. And many of those saves were likely ultralight type vehicles (to use the FAA term) with questionable (to me) structural integrity, flown by "pilots" with little to no training.Warmi wrote:GRS chutes descent at about 14 mph arriving as if dropped from a height of 1.8 m and are designed to have the plane land horizontally using landing gear as its cushion ( which is the only structural part of a typical LSA designed to actually absorb large impact forces )
Sufficient to say, as far as available data indicates, there has never been a deployment that resulted in a serious injury due to a successful chute deployment.
The technical data on their website shows the LSA-rated chutes descend at vertical speeds between 7.1 and 7.5 meters per second at 600 kilos (1320 lbs). That translates to roughly 1400-1475 fpm (15.9 to 16.8 mph). The claim that their chutes are designed to land with the plane touching down horizontally using the landing gear as its cushion is ludicrous. The chutes are round, and there are no "steering lines" for the pilot to control. The airplane attachment bridle connects to the chute bridle at a single point, therefore the only force acting to "align" anything in that equation would be the aerodynamics of the airplane, causing it to eventually align with the prevailing wind. Thus any "horizontal" component will be minimal, and basically wind-directed. There is no way to predict whether the plane will land perfectly vertically (thin odds) or be drifting right/left/forward/back at the time of impact.
With a 10-mph wind, you'd be dealing with both the vertical component and the horizontal component, thus the total angular velocity at impact using the average of 16.3 mph vertical component (7.3 m/s) would be approximately 19.1 mph (simple Pythagorean principle math: square root of (16.3 squared + 10 squared). Aside from that, GRS' technical data also shows that it requires 6 seconds from the time you pull the trigger before you would have a fully deployed chute. Their diagrams (and videos of actual chute deployments) show significant pendular action would result from a chute deployment. If you're low when you deploy, that pendular action could either decrease or increase the horizontal component of the forces, depending on whether you impact the ground swinging into or away from the drift direction. Of course, if the wind is blowing perpendicular to the "swing", you've got yet another force component to be dealt with. How good is the side impact protection on your airplane (or ANY airplane, for that matter)?
Obviously, the higher you deploy the chute, the less a factor that 6-second delay and the "swing factor" become, but "holding off as long as possible" before deploying the Cirrus "CAPS" system was leading to a LOT of injuries and fatalities in Cirrus airplanes. Their accident / fatality record was significantly higher than expected (higher than Cessna's for single-engine planes, for instance). They started a massive educational campaign with specialized training focused on using the CAPS properly (pull high and early), and insurance companies began requiring that training before they would insure or renew policies. They eventually got it turned around, and now their record is somewhat better than the rest of the fleet.
But that's the whole point of Bob Hoover's advise to "Fly the airplane as far into the crash as possible." You're never out of options as long as you have some degree of control. There have been literally thousands of people who've experienced engine failures in flight in single-engined airplanes. Their accident survival rate is actually higher than that of twin-engined aircraft that also have a single engine fail in flight. (That's a twin-engine pilot training issue, but let's not go there right now.) Selecting the best crash site, and flying the aircraft to that site under control, using whatever aerodynamic and mechanical braking available before impacting that "immovable object" leads to surprisingly low injury and fatality rates. Yes, you may initially touch down at 35-45 mph, but if you're flying the airplane under control, you shouldn't hit anything hard at that speed. By using maximum braking action (or aiming the airplane between smaller trees) you can reduce the G-forces of the deceleration if/when you finally do hit something immovable.Warmi wrote:Personally ,if given enough reasonably clear space to land, I would always opt for a normal emergency landing but ... if you are out of options, even most skillfully executed emergency landing will result in about 35-45 mph forward velocity impact which is much more likely to result in a serious injury than the chute based 14 mph vertical descent alternative.
I'm a big proponent of "keeping things simple" in aviation. The fewer decisions that must be made in an emergency situation, the better the odds I'll get it right. Most studies show that it takes 6 seconds after an engine failure for the pilot to get over the shock and react. Hopefully, that reaction is pushing the nose over to roughly "max glide" speed, then selecting and turning towards the best available emergency landing spot (critical!). Then we run the engine failure emergency checklist (fuel and magnetos are the major items, right?). So we're maybe 20-30 seconds after the engine quit, and we've lost probably 500-800 ft of altitude (and possibly a lot more). So, how long can I hold off the decision to pull the chute, before I'm too low to do any good with it? The GRS tech data says minimum deployment height is roughly 110 meters (360 ft), so I gotta pull above that altitude or I've just made matters worse. If I was 1500 AGL when the engine quit, I might have <5 seconds between "stabilized at Vg, heading toward my selected landing spot" and the minimum altitude to pull the chute. Not much time to think through the variables and come to an educated decision...
If you elect to go with a chute, PLEASE think through these scenarios ahead of time, and establish FIRM parameters on where and when you WILL pull the chute. Don't be like those early Cirrus pilots, and put it off until it can no longer help you! Better to pull early, and have the insurance company's airplane destroyed than to pull too late.