# Escaping a falling helicopter **URL:** \ **Category:** Factual Questions\ **Created:** [May 7, 2003, 9:11pm UTC](https://boards.straightdope.com/t/escaping-a-falling-helicopter/173763 "2003-05-07T21:11:56Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![criminalcatalog](https://avatars.discourse-cdn.com/v4/letter/c/e68b1a/32.png) [@criminalcatalog](https://boards.straightdope.com/u/criminalcatalog)\ **Post date:** [May 7, 2003, 9:11pm UTC](https://boards.straightdope.com/t/escaping-a-falling-helicopter/173763/1 "2003-05-07T21:11:56Z")
Okay, so a jet pilot can eject from a falling plane vertically. So, from high altitudes, and assuming the rotors are still going full speed, how does a helicopter pilot escape? Can they jump out the side without having to worry about the blades above them? ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [May 7, 2003, 9:24pm UTC](https://boards.straightdope.com/t/escaping-a-falling-helicopter/173763/2 "2003-05-07T21:24:52Z")
I don’t know for certain but here are some thoughts. All objects fall at the same speed regardless of theri weight. Theoretically if your helicopter is falling like a rock then you are too. If you jump outside the helicopter you should retain a position right next to the helicopter. Of course, the real world is a bit different. However, chances are the helicopter is not falling like a rock…especially if the rotors are spinning as suggested in the OP. Therefore you should be able to fall faster than the helicopter as its rotors are still providing some lift. Just be sure to jump out and down rather than jumping up into the rotors (shoud go without saying). Also realize that even if the helicopter loses all power helicopters are capable of something called autorotation. As the helicopter falls downward wind passing the rotors causes them to spin and provide lift. IIRC this can be sufficient to land some helicopters safely even if all power is lost (lookup info on an autogyro which uses this principle almost exclusively). Even if the fall rate is too high for a safe landing it still means your helicopter will have some lift such that you should be able to fall away from it quicker than it is falling and avoid getting diced by the rotor blades. ---
**Author:** ![bernse](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@bernse](https://boards.straightdope.com/u/bernse)\ **Post date:** [May 7, 2003, 9:44pm UTC](https://boards.straightdope.com/t/escaping-a-falling-helicopter/173763/3 "2003-05-07T21:44:53Z")
Some helicopters (the Hokum for example) have ejection seats. They have explosive charges that go off slightly before ejection to seperate the blades off of the rotor shaft. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [May 7, 2003, 10:02pm UTC](https://boards.straightdope.com/t/escaping-a-falling-helicopter/173763/4 "2003-05-07T22:02:13Z")
Helicopters are inherently unstable. That’s why you _never_ let go of the cyclic stick in a helicopter. (Note: A few helis have autopilots, and others can fly for a little bit with the cyclic friction on – but generally speaking: Don’t let go.) If you release the cyclic you never know which direction the helicopter will “fall off”. You might roll, or you might get a boom chop. So if you try to bail out of a helicopter, you’re taking a chance that you’ll go through the food processor. In case of a power failure you do what **Whack-a-Mole** said and autorotate to a landing. If you’re over water, then autorotate down and when the skids hit the water roll the helicopter to stop the rotors. (If you have partial power, hover to let any passengers off, then fly off a safe distance and “land” and roll as above.) Sometimes you don’t have that option. I posted on the boards about the POH for the Robinson R-22. It actually uses the word “doomed”. I have seen video footage of an R-22 that lost rotor RPM. (Pilot error.) It just fell out of the sky. ---
**Author:** ![DiLLiGaF](https://avatars.discourse-cdn.com/v4/letter/d/45deac/32.png) [@DiLLiGaF](https://boards.straightdope.com/u/DiLLiGaF)\ **Post date:** [May 7, 2003, 10:03pm UTC](https://boards.straightdope.com/t/escaping-a-falling-helicopter/173763/5 "2003-05-07T22:03:56Z")
> [@](#): > > \*Originally posted by Whack-a-Mole \* > \*\*Therefore you should be able to fall faster than the helicopter as its rotors are still providing some lift. \*\* I sure would hate to have to test that theory! ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [May 7, 2003, 10:06pm UTC](https://boards.straightdope.com/t/escaping-a-falling-helicopter/173763/6 "2003-05-07T22:06:21Z")
**bernse** : I was going to mention that, but I got side-tracked by an Easytrieve. 😉 ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [May 7, 2003, 10:26pm UTC](https://boards.straightdope.com/t/escaping-a-falling-helicopter/173763/7 "2003-05-07T22:26:07Z")
> [@](#): > > \*Originally posted by DiLLiGaF \* > \*\*I sure would hate to have to test that theory! \*\* Me too! Still, if your option is certain death in a crashing helicopter (say you’re in the R-22 mentioned by **Johnny L.A.** ) then why not take your chances? This assumes of course that you have a parachute and are sufficiently high enough to make use of it. Your chances may be slim but slim is better than none at all. ---
**Author:** ![Nanoda](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Nanoda](https://boards.straightdope.com/u/Nanoda)\ **Post date:** [May 7, 2003, 10:28pm UTC](https://boards.straightdope.com/t/escaping-a-falling-helicopter/173763/8 "2003-05-07T22:28:22Z")
There are several ways to eject from a helicopter. Plain old “bailing out” is so passe. 😉 Do they even give you a parachute as a non-ejection pilot? Usually, you have explosive bolts on the blades, like bernse sez. Blow them, and rotation means they’re gone. Then you want to jettison the canopy and use a mostly-regular ejection seat. If rigging exploding bolts is too much of a chore, there’s always out the side. I personally find the thought of extreme lateral acceleration to be bad for you, spinally speaking, but it’s better than nothing. I’m almost sure someone’s used this, but I can’t find a site to cite. Out the bottom! Now, I don’t know of any helicopter that does this, but several airplanes and many large bombers have/had this feature. (B-52, for example) I suppose there was less in the way, or something. Of course, usually when you _need_ to eject, you’re usually low and right-side up. But if it doesn’t work for you, are you gonna complain? 😉 ---
**Author:** ![MonkeyMensch](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@MonkeyMensch](https://boards.straightdope.com/u/MonkeyMensch)\ **Post date:** [May 7, 2003, 10:47pm UTC](https://boards.straightdope.com/t/escaping-a-falling-helicopter/173763/9 "2003-05-07T22:47:09Z")
Goddamn **Johnny L.A.**! can I caome get a ride with you some time? 😉 I was out at the air field at Pendleton where a friend of mine flies frogs (CH-46 Marine helos). I chanced to be there on a day when some squadron mates were doing autorotation parctice. Now I have a pretty good understanding of aerodynamics and all but I had always assumed that autorotation was like gliding. You know: rotary wings, the wings are still there, we’ll just glide back in to the field. I couldn’t believe it! I looks like the pilot cuts power, throws the collective on the floor and only yanks it back when there’s a hundred feet or so of air left. ( **Johnny L.A.** please come back to this thread and tell about autorotation practice and qualifying) ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [May 7, 2003, 11:02pm UTC](https://boards.straightdope.com/t/escaping-a-falling-helicopter/173763/10 "2003-05-07T23:02:11Z")
**MonkeyMensch** : I’m not current at the moment. I’ll need to get up for some refresher training and Biennial Flight Review. But once I’m current, if you happen to be in the area on a flying day I almost always have an empty seat. Autorotations are _fun!_ It’s like your own personal roller coaster a thousand feet in the air. In the little helicopters I fly, we start to flare at about 40 feet. There’s actually a lot going on. You need to keep your rotor RPM in the green arc (too slow and you fall out of the sky, too fast and you can damage it). You need to adjust your glide with your cyclic and watch the speed with the collective. Of course moving the cyclic fore or aft changes the rotor speed, so you have to adjust the collective. If you’re soming into a power recovery (instead of touching down, you add power and come into a hover), you need to be ready on the pedals because you’ll need to counteract torque as soon as you add any power. As I said, it’s a blast! 🙂 Private pilots do not need to demonstrate an autorotation to full-touchdown; only to a power recovery. The place where I rent the heli prohibits autorotations unless an instructor is on board. (They also prohibit over-water flights. Insurance issues.) One time I showed up for a lesson and the heli was overdue. Turns out they were doing a full-touchdown auto and snagged a rock at the last instant. Rolled the aircraft into a ball. I rented a Cessna that day, and went up in a different heli the following week. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [May 7, 2003, 11:10pm UTC](https://boards.straightdope.com/t/escaping-a-falling-helicopter/173763/11 "2003-05-07T23:10:11Z")
> [@](#): > > \*Originally posted by Johnny L.A. \* > _Turns out they were doing a full-touchdown auto and snagged a rock at the last instant. Rolled the aircraft into a ball._ > > **…I almost always have an empty seat.** And this is surprising how? 😉 ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [May 7, 2003, 11:47pm UTC](https://boards.straightdope.com/t/escaping-a-falling-helicopter/173763/12 "2003-05-07T23:47:16Z")
> [@](#): > > \*Originally posted by Johnny L.A. \* > \*\*Sometimes you don’t have that option. I posted on the boards about the POH for the Robinson R-22. It actually uses the word “doomed”. I have seen video footage of an R-22 that lost rotor RPM. (Pilot error.) It just fell out of the sky. \*\* My ex woud get a kick out of that as he used to insure Robinsons. His agency eventually stopped insuring the things as they kept falling out of the sky, and their surviving customers couldn’t afford the rising premiums. The big “gotcha” on Robinsons is the rotor is, compared to other helicopters, ultralight, and has little rotational inertia by design. In case of engine failure, you’ve got roughly one second to grab whatever collective you can and hope to autorotate. Otherwise, the rotor stops spinning about a second after power loss and you’re in an expensive rock. And doomed? Oh my… :eek: > [@](#): > > SAFETY NOTICE SN-24 (clipped and paraphrased) > > LOW RPM ROTOR STALL CAN BE FATAL > > Rotor stall can occur at any airspeed and when it does, the rotor stops producing the lift required to support the helicopter and the aircraft literally falls out of the sky. > > When the rotor stalls, it does not do so symmetrically because any forward airspeed of the helicopter will produce a higher airflow on the advancing blade than on the retreating blade. This causes the retreating blade to stall first, allowing it to dive as it goes aft wile the advancing blade is still climbing as it goes forward. The resulting low aft blade and high forward blade become a rapid tilting of the rotor disc sometimes referred to as “Rotor Blow-back.” Also, as the helicopter begins to fall, the upward flow of air under the tail surfaces tends to pitch the aircraft nose-down. These two effects, combined with aft cyclic by the pilot attempting to keep the nose from dropping, will frequently allow the rotor blades to blow back and chop off the tailboom as the stalled helicopter falls. > > Due to the magnitude of the forces involved and the flexibility of rotor blades, rotor teeter stops will not prevent the boom chop. The resulting boom chop, however, is academic, as the aircraft and its occupants are already DOOMED by the stalled rotor before the chop occurs. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [May 8, 2003, 12:38am UTC](https://boards.straightdope.com/t/escaping-a-falling-helicopter/173763/13 "2003-05-08T00:38:04Z")
> [@](#): > > In case of engine failure, you’ve got roughly one second [to lower the collective] No you don’t. 😛 Actually, you have to get the collective down _immediately_. (Or as near to “immediately as possible”.) 😉 [quote] The big “gotcha” on Robinsons is the rotor is, compared to other helicopters, ultralight, and has little rotational inertia by design. [quote] I think the low-inertia rotor system (or “ **no** -inertia” as we like to say) is more a product of the aircraft’s size than that Frank Robinson was out to design a low-inertia rotor system. I normally fly a Schweizer 300CB, and it also has a low-inertia rotor system – but it has more than the Robbo. While having a low-inertia rotor system is something of which you certainly must be aware, I think the main reason why R-22s crash is because they are training aircraft. Flying a helicopter takes a certain amount of care, and low-time pilots can get into trouble when they lack experience. You can get into a negative-g situation or retreating-blade stall in a Bell JetRanger just as easily, but it rarely happens because JetRanger pilots have more experience. Also, many helicopter pilots are airplane pilots first (as was I) and some things you would do in a fixed-wing are exactly the wrong things to do in a helicopter. For example, a fixed-wing pilot might push the nose down abruptly in a nose-high situation. If you do that in a helicopter with a semi-rigid rotor system, you may cause a mast-bumping incident. A severe mast-bumping incident can cause the rotor system to depart the aircraft. This would not be a good thing. One good thing about helicopters is that they are relatively safe to crash in. Four of the helicopters I’ve flown – all R-22s – were crashed by other people. No injuries aside from some bumps and bruises. I nearly bought a Hughes 269A a couple of years ago, but the insurance was a deal-breaker. I just can’t afford $1,000/month for insurance! Heck, at those rates, in three and a half years I could have bought another helicopter! Oh, in fairness, the word “doomed” isn’t actually capitalized in the POH. 😉😃 ---
**Author:** ![MonkeyMensch](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@MonkeyMensch](https://boards.straightdope.com/u/MonkeyMensch)\ **Post date:** [May 8, 2003, 12:45am UTC](https://boards.straightdope.com/t/escaping-a-falling-helicopter/173763/14 "2003-05-08T00:45:09Z")
And these previous three posts are a perfect example of why I post on the SDMB. **Johnny L.A.** I hope you’re not kidding about that empty seat. I also have a line with my buddy at Continental about a ride in the flight deck. Oh, please, oh, please. (Friggin’ terrorists!) ---
**Author:** ![Klaatu](https://avatars.discourse-cdn.com/v4/letter/k/e0b2c6/32.png) [@Klaatu](https://boards.straightdope.com/u/Klaatu)\ **Post date:** [May 8, 2003, 4:19am UTC](https://boards.straightdope.com/t/escaping-a-falling-helicopter/173763/15 "2003-05-08T04:19:28Z")
From **Johnny L.A.** > [@](#): > > A severe mast-bumping incident can cause the rotor system to depart the aircraft. This would not be a good thing. That cracked me up! I used to fly puddle jumpers back in the 70’s and 80’s, and yes it would not be a good day to see various bits “departing” the aircraft. ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [May 8, 2003, 5:46am UTC](https://boards.straightdope.com/t/escaping-a-falling-helicopter/173763/16 "2003-05-08T05:46:04Z")
“Our rotors have departed the aircraft so we’ll be landing ahead of schedule.”