Very good idea. Throw out the raft before ditching.
Here is a picture after I ditched in my Cirrus. OK, I admit it. Iwas a bit over gross weight.
I was wondering why the plane wouldn’t get off the ground and ran off the runway.
In reply to:
frankly, I’d be tempted to toss the raft out on the way down, yanking the inflate cord as it went out the door.
If I remember correctly from a survival course I attended, this would be a particularly bad idea. Even in a nearly ideal ditching, with the raft deployed after the aircraft is stable in the water, it was recommended that the life raft’s umbilical rope be held so that the raft remains very near the airplane, to prevent it from drifting away. If it’s done correctly, it may be possible to step from the wing directly into the raft. On the other hand, it’s no fun to be swimming after a drifiting life raft. I imagine that the problem would be much worse if the raft were deployed before splashdown!
Disclaimer: I’m no expert, and my memory is often faulty, so I could be completely wrong.
- Mike.
In reply to:
Funny you should raise this. I have wondered for some time why aircraft manufacturers do not fill the empty spaces in wings, lower fuselage etc with a light buoyant material. I even discussed this with Ian Bentley earlier this year and we thought about the possibility of filling the spaces with bags of ping pong balls! The additional weight is negligible, but certainly considerable buoyancy can be achieved. I recently played with some lightweight porous plastic cylinders in a swimming pool and from the way they were able to support my own weight I worked out that something like 10-15 cylinders of the stuff each of a length of about 1 metre and diameter 10 cms should be easily enough to support 3000lbs in water. Even if one did not achieve full floatability, anything of this sort added in the lower parts of the aircraft would help.
Mike,
Thank you for not letting me think I am crazy. I have seen what modern foam can do to avoid boats sinking, even when they are FULL of water (Large Catamarans). Maybe in the future someone will design a brilhant idea like the CAPS to maintain the Cirrus floating. I always learned that the raft is our LAST option in boats. Never abandon your boat before it abandon you…
All the best and thanks to everyone that brought some light to my question.
Homero
In reply to:
Also, attach the lanyard to the airplane BEFORE you take off. You have no idea what the crash, er landing, uh…impact sequence will be, nor do you know if you will remember to attach it before you throw it! If the raft doesn’t have a water activation device, it will sink.
The Winslow Island Flyer life raft that is sold in the Cirrus Store and demonstrated at both of the Cirrus Migrations does not have a water activation device but does float, even if uninflated.
Cheers
Rick
Dennis,
That was too interesting NOT to pursue… here’s what I found at a site about PanAm accidents:
Clipper Sovereign of the Sky 10/16/1956
Boeing Stratocruiser(N90943)
Location: Over the Pacific Ocean
Route: San Francisco - Honolulu
31 Aboard / 0 Fatal
The aircraft ditched into the Pacific Ocean while on a flight from San Francisco to Honolulu after losing the No. 1 and then the No. 4 engine. The aircraft circled around and landed in the water near a USCG weather ship.
Interesting that the report mentions the loss of the #1 and #4 engines - the photo seems to show that #4 is the only engine running?
- Mike.
Oh and one more thing: I make all right and rear seat occupants close their eyes and open the door and find the handle to pull themselves up prior to engine start. If the cabin is flooded or something causes them to lose their sight, they know how to egress.
I also do something on the MFD that many are starting to incoporate: On the checklist page prior to takeoff, I place the engine out checklist on the page. In case of a brain freeze, its right there.
[quote]
Oh and one more thing: I make all right and rear seat occupants close their eyes and open the door and find the handle to pull themselves up prior to engine start. If the cabin is flooded or something causes them to lose their sight, they know how to egress.
quote]
Most Excellent! If one has not considered the disorienting effects of being inverted and submerged, you probably won’t make it out. Most fatalities in ditching situations come from being trapped in the aircraft and unable to egress. The first time that dunker hit the water and rolled it took 2 divers a few tense moments to help some very humbled pilots out and to the surface. (Then we put blackout goggles on to simulate night or deep submersion and THAT was a B----! The key is to find a handheld landmark and realize which way you’re going to egress in relation to the handhold. here is more info.
[quote]
The Winslow Island Flyer life raft that is sold in the Cirrus Store and demonstrated at both of the Cirrus Migrations does not have a water activation device but does float, even if uninflated."
and that’s a great feature! That particular raft is highly rated and once again Cirrus gets kudos for safety in choosing well! I still recommend attaching the lanyard before takeoff if at all possible. At any rate, the lanyard should be attached before deploying, so high winds or current do not take the raft. You can’t swim fast enough to catch it, esp if injured. You can also follow the mooring line to the raft, and it usually ends up at the boarding point.
Being familiar with the operation and contents of your raft (or any survival equipment) before you go is vital. I have spoken with many, who do not even realize there is a lanyard or know how to manually inflate the raft.
If you jump off a bridge, I think you would agree that hitting water from any significant height is similar to hitting the ground.
Since no one has dropped a Cirrus into water, your question does not have an exact answer. Given the total mass of the airplane versus the relative mass of the gear, and given the fact that hitting water DOES offer significant resistance, I am not convinced the differences between a water and land chute landing are THAT significant.
Given the fact that a chute landing is at 18 mph and a ditch would be at 70 mph, I’ll take the chute any day.
In reply to:
If you jump off a bridge, I think you would agree that hitting water from any significant height is similar to hitting the ground.
Since no one has dropped a Cirrus into water, your question does not have an exact answer. Given the total mass of the airplane versus the relative mass of the gear, and given the fact that hitting water DOES offer significant resistance, I am not convinced the differences between a water and land chute landing are THAT significant.
Given the fact that a chute landing is at 18 mph and a ditch would be at 70 mph, I’ll take the chute any day.
My understanding is that the landing gear and the seat absorb some of that 18mph impact.
In a water landing, the gear would absorb none of the impact, and we both agree that the impact is roughly just as hard on water as on land.
The seat will not absorb more impact, so your body would be absorbing the extra impact that the gear is not absorbing (because the gear would not crush as it hits the water in the same way it would as it hits hard land).
Or am I wrong?
I am not sure tat is correct. The landing gear still WILL absorb impact hitting water. MAYBE not as much as on land, but there is still a tremendous resistance when the gear hits the water at 18 MPH so the energy of impact will transmit to the gear to some degree.
As far as the seats are concerned, the Cirrus seat is designed to absorb 26 G’s of energy. The chute will not causethat much of an impact on land or water so that point is moot.
Would you fear a drop into a swimming pool from 12 feet? Probably not. (The equivalent drop height for the impact velocity is about 12 feet.) How about from 100 feet? Of course. Water doesn’t take on cement-like qualities unless you impact it with missile-like velocities. Picture a 12 foot dead drop of the airplane into a swimming pool. This would be more “wheeee!” than “whoa!”
Unless there is significant lateral velocity due to surface winds exceeding 30 knots, my opinion is that CAPS is a no-brainer when it comes to ditching the airplane. An 18 knot event is almost always going to be better than a 70 knot event.
If you’d join COPA you’d find many very interesting threads in the Members Forum, including some by noted, published, Physicists.