But by reading the list of incidents and particularly their causes and number of fatalities you can get a pretty good idea of the risks associated with some machines.
Crab, it's pretty hard to disagree with that statement, but I'll try!
Seriously, I really don't disagree that you can come to some conclusions by looking at the accident data, but there are a lot of factors to think about. People have always pointed out that one of the reasons Robinson helicopters crash so much is because they're flown by so many inexperienced pilots. So, when a low time pilot bumps the mast is that a failure of the pilot or of the machine? As you yourself said:
why the hell not? It makes a laughing stock of the certification process which is supposed to ensure the aircraft is airworthy.
So, why are we allowing new aircraft (R66, Bell 505) to continue to be certified with teetering systems?
Originally Posted by
aa777888
And I've done that with the FAA data.
I did a similar search, looking at fatal accidents that occurred in cruise flight. Not unsurprisingly, a lot of them are iIMC/weather and CFIT types of accidents. People have been drilling that into us for years (and yet we still keep doing it). But as aa777888 says, all the teetering systems are represented: Bell, Robison, Hiller. It's actually a bit chilling how many of them there are. So, should the FAA still be certifying teetering systems? I must admit I was a little disappointed when Bell used the L4 rotor system for the 505. I was hoping for a mini-407 rotor system for that aircraft. Maybe you just can't get a machine with 4 blades to compete price wise with a 2 bladed machine like the R66.
Originally Posted by
gator2
I fly a 44 because its all I can afford. I've been in some awfully rough air, and just slowed down. I have, however, been pretty damn scared a couple of times when a passenger has bumped the cyclic, trying to take a picture, or get to their cell phone or whatever. If I'd had a little looser grip on the pole I think I'd be dead. I wonder how many of the inexplicable smooth clear air disintegrations are due to that?
It's an interesting question. For the first 10 years I taught, we were required to teach low gee pushovers (by my school, and then later by the FAA in SFAR 73). It takes a pretty good cyclic push or some pretty turbulent air to start getting right rolls. When I've been flying in 30G45 I'll get some gentle right rolls and it's pretty obvious to anyone trained in teetering systems that it's time to slow down in those conditions. As for the push, if someone shoves your cyclic by mistake, yeah, it's a concern, but as long as it doesn't pop out of your hand I think it's unlikely that you'll go low gee - your reaction to put the cyclic back where it was is probably fast enough to avoid mast bumping (unless, I dunno, they manage to make it go full deflection?). In any case, I think that holding the cyclic with your fist rather than two fingers in cruise is probably not a terrible idea.
Like most people, I'm not in love with the Robinson T-bar cyclic. Most people don't know, but the first 2-3 R22s had narrower cockpits. I've got lots of time in the #2 R22 (the FAA crashed #1) and the cockpit was so narrow that it was difficult to do hovering autos from the left seat - trying to get your wrist around the throttle enough so that you'd be able to roll it all the way off, your hand/wrist would hit the door. They widened the cockpit a bit on the production aircraft (so, when Frank was designing the T-Bar, there was even less room than there is today).
The R44 and R66 don't have that excuse; there's plenty of room for a conventional cyclic and this would reduce a couple kinds of problems:
The first is what was mentioned above - the fact that the push-pull tube for the cyclic is mounted on the aircraft centerline, and that even with the left hand cyclic grip removed there is a small stub sticking out to the left, it's quite easy for a passenger to inadvertently hit the cyclic in flight. Photographers and females with handbags always arouse my suspicion
The other problem is that if an instructor is guarding the cyclic from the left seat while the student pilot is flying from the right, the instructor's cyclic grip is something like 6-12 inches in the air (because of the way the cyclic teeters on the central control rod). When the student moves the cyclic, they can move it in pitch and roll, but they can also move it in "teeter" which means the CFI has a 3 dimensional problem of trying to keep his hand near the cyclic grip... if the student does a quick move including moving his hand up or down it can be difficult for the CFI to retain control of the cyclic. It's not an huge problem for the CFI, but it does make it more difficult. I would be totally happy if Robinson installed conventional cyclic controls in the R44 and R66.
The recent caution range for the Robinson airspeed indicator is an interesting development. The amount of cyclic push you need to get below 0.5 gees is directly related to your speed... At 120 knots a pretty gentle push will get you light in your seat... At 60 knots it takes a pretty aggressive push. We could change the R22/44/66 Vne to 60 knots when a non-rated pilot is at the controls... That would put you in Schweitzer/Bell-47 territory for speed, but arguably there's no reason for a student pilot to be going all that fast. It might also provide an incentive for Robinson to change their head design to one less influenced by low gee...