Now you lose your head!

March 25, 2008 9:52 AM

Do you really need to duck when getting in/out of a helicopter?

You see it all the time in movies and while I haven't been in a helicopter since childhood (air shows) I thought a helicopter was high enough off the ground not to chop your head off.

Is decapitation a real concern or do people do this just because we see it on TV?

posted by doorsfan to Grab Bag (24 answers total)

No, you don't, the main rotor is high enough. But the main rotor create an impressive downwash and most people have the reflex to duck because of that downwash.
posted by racingjs at 9:58 AM on March 25, 2008

This is mostly a problem if the helicopter is powering down after landing; not so much if they're maintaining rotor head speed to lift off again.

Helicopter blades are very flexible (and those that aren't have engineered "feathering" hinges built into them to replicate the flexibility). As the blades spin down, they have less centrifugal force on them, and they begin to droop. They can easily droop enough to take off a head.

Even if they didn't droop, I still think that I'd duck away from them as far as I could.
posted by Netzapper at 10:00 AM on March 25, 2008

I do it because there's a huge whirling blade not too far above my head. A huge, whirling, flexible blade attached to an extremely light chassis that is subject to gusts of wind.

That said, I've never been in a Chinook or any of the other big helicopters. I might not feel the need to duck there.
posted by tkolar at 10:00 AM on March 25, 2008 [1 favorite]

I did it while getting off in the Marines because those things are scary as hell when they are whizzing over your head. It's the same reaction a pitcher has when a batter lines a ball five feet over his head.

Also, when you exit off the back and they say make sure you turn right because if you turn left you will die when you walk into the rear rotor I can guarantee you that it is physically impossible to turn left. Your brain won't let you.
posted by zzazazz at 10:03 AM on March 25, 2008 [1 favorite]

Not strictly apropos, but Rotor Blades Are Expensive.
posted by tkolar at 10:03 AM on March 25, 2008 [6 favorites]

I jumped in and out of helicopters a few times while in the Territorials in the UK, from small Gazelles up to big old Chinooks. When the rotors are spinning down, they definitely feel like they could chop your head off. It's kind of instinctive to be honest - the whomp whomp whomp of the blades is really loud when you're right under them.
posted by Happy Dave at 10:10 AM on March 25, 2008

Possibly of interest: Philip Greenspun's Helicopter Passenger Safety Card: Don't put your trust in God or the pilot: remain in the helicopter until all blades have stopped spinning. If this is not practical, approach or exit the helicopter while ducking slightly.
posted by Mapes at 10:19 AM on March 25, 2008

Helicopter blades are very flexible (and those that aren't have engineered "feathering" hinges built into them to replicate the flexibility).

Those would be "flap" hinges, feathering is along the axis of the blade.
posted by Chuckles at 10:30 AM on March 25, 2008

Here in the northwest, we had someone in the news recently for getting killed by chopper blades being lower on one side, because the chopper had landed on a slight slope, as I recall, but reports say tail rotor, so not exactly your scenario.
posted by nomisxid at 10:30 AM on March 25, 2008

There's a great scene in the West Wing where President Bartlett and Charlie have a fight over whether you have to duck when you get on a helicopter. I'm trying to find a clip or a link to the dialogue, it was great...
posted by ThePinkSuperhero at 10:35 AM on March 25, 2008 [2 favorites]

I jumped out of Hueys, Blackhawks and Chinooks, and ducked when boarding them every single time. The few times I walked out of them I ducked, too. It may not have been absolutely necessary, but the downwash from the blades feels so close that, like a lot of the previous answerers said, it felt like it would be really dangerous not to.
posted by cog_nate at 10:36 AM on March 25, 2008

I worked at the local airport while I was in high school. I was exposed to a few different types of helicopter and had to do some "hot" fueling (while the engine is on and blades are spinning), so here's my two cents:

Training helicopters like Robinson R22s and R44s have the rotor high enough up that it's just about impossible to hit your head on them, even when nothing's spinning and the blades are drooping. However, the filler caps for the fuel tanks are on top of the fuselage, requiring a ladder to get to, so I wouldn't recommend going up there until everything has stopped moving. The blades are heavy - a couple hundred pounds each, I believe, so even if they're freewheeling (which they do for quite awhile after the engine is cut off) you could get pretty banged up if you hit one.

Bell Jet Rangers seemed pretty benign to me. These are popular with news channels. The rotor plane is parallel to the ground, so you can walk under it no problem.

Larger craft like the Bell 206 or the Augustas actually have the rotor plane at an angle to the ground, so the tips of the blades are closer to the ground at the front of the helicopter. You will definitely lose body parts if you walk towards the helicopter from the front while the rotor is spinning. Some of them (I think the 206 has it) have a hand brake to stop the rotor while the engine is still running, but if the pilot lets go of the brake you will get hit by the rotor. I was always told to approach from the side on those. When switching sides (they have fuel ports on both sides), walk all the way out from under the rotor disk, go all the way around the front, then approach again from the other side.

It's really hard to tell where the rotor disk ends when the rotor is spinning, so if you're going to park a vehicle nearby (say, a tanker truck filled with thousands of gallons of jet fuel), stay well clear. You do get used to it, eventually, and even though I tended to stoop a little near them it was mostly to keep flying debris out of my face.
posted by backseatpilot at 10:37 AM on March 25, 2008 [3 favorites]

I am quite shocked by the stuff that a search for "helicopter decapitation" will turn up - wouldn't there be a design requirement to keep the blades at safe heights when operating?
posted by themel at 10:38 AM on March 25, 2008

wouldn't there be a design requirement to keep the blades at safe heights when operating?

My mom dated a rotorhead for a while and from what I remember, the blades can't be too rigid or the helicopter won't fly well (if at all). On landing, the blades are moving pretty slow and they "droop." As Dasein said, you've got to be most careful near the ends of the blades, yest ye get a haircut you'll never forget.
posted by Nelsormensch at 11:05 AM on March 25, 2008

yest ye get a haircut you'll never forget

Or, will forget immediately.
posted by nicwolff at 11:24 AM on March 25, 2008 [3 favorites]

A wildlife biologist was killed in Washington State last year by walking into moving helicopter blades (link). According to this article:

Spencer was hit by the rotating blades of a helicopter when he got out of the chopper in the Yakima River canyon north of Yakima. Officials said the helicopter landed on a slope, causing the blades to point downward more than usual.
posted by Forktine at 11:30 AM on March 25, 2008

friend of brother was decapitated. it happens.
posted by randomstriker at 11:37 AM on March 25, 2008

Transported offshore for 6 years in various helicopters from SuperPumas, Bell, Augusta, Dauphins in all kinds of bad weather.

You duck your head as a matter of course. Like others have said, on some choppers the blades may pitch down at the front, and you don't want to be heading back towards the tail rotor. Walk straight out at 90 degrees from the side of the chopper and follow the deck crew instructions and you're ok.

Absolutely do not stop and take photos of your mates coming off the chopper whilst the blades are turning. As some poor woman learnt on a Norwegian platform a few years ago, this is is a fatal mistake.
posted by arcticseal at 11:54 AM on March 25, 2008

I've entered and exited Sea Kings while they were rotating and while the rotors are high enough they're not going to chop your head off, just try NOT ducking.

Bonus anecdote: we were filming with the Royal Navy once and had to land a camera crew on a destroyer coming back into Portsmouth from the Azores. It was part of a film about Naval discipline and policing and we wanted to film a drug-raid. The film was not exactly popular with the Fleet and we were fighting a continual battle to keep the access open. Anyway, we were told that the Sea King was too big to land on the helo deck of the ship in question, so we had to be winched out in the middle of a storm. I was wearing a suit, which is what we had to do since we were considered officers for the duration. When we landed on the heaving deck and were escorted, soaking and dizzy, into the wardroom, the XO asked why they'd winched us on board.

"Because the Sea Kings are too big too land", I told him knowledgeably.

"No they aren't", he said. "We land them all the time".

There were a lot of smirks on a lot of Naval faces when we got back to Portsmouth.
posted by unSane at 11:57 AM on March 25, 2008 [2 favorites]

wouldn't there be a design requirement to keep the blades at safe heights when operating?

There are no strict design requirement according to Federal regulation regarding safe rotor height. This is what I could find in the FAR :

This one is obvious :

Sec. 27.661 - Rotor blade clearance :
There must be enough clearance between the rotor blades and other parts of the structure to prevent the blades from striking any part of the structure during any operating condition.

This one is laconic :

Sec. 27.783 - Doors :
Each external door must be located where persons using it will not be endangered by the rotors, propellers, engine intakes, and exhausts when appropriate operating procedures are used. If opening procedures are required, they must be marked inside, on or adjacent to the door opening device.

The requirements for the tail rotor are a bit more stringent :

Sec. 27.1565 - Tail rotor
Each tail rotor must be marked so that its disc is conspicuous under normal daylight ground conditions.
posted by racingjs at 2:40 PM on March 25, 2008

Also, you want to get away quickly, in case this happens.
posted by you're a kitty! at 2:48 PM on March 25, 2008

There's always the Pan Am disaster, which killed five people including horror director Michael Findlay, when a landing gear strut failed during boarding. Not a nominal condition, though.

The Encyclopedia of Occupational Health and Safety has a chapter on helicopters, but while they mention the danger of rotors and the importance of briefing, they don't specifically say that you should duck while walking under the main rotor. They are more concerned about the pilots being aware of the positioning of the tail rotor when possible away from passenger entry or egress paths.

On the other hand, First Responder: Your First Response in Emergency Care points out that main rotors can sweep as low as 4 feet off the ground, and one of their five safety points is "Keep low when you approach the helicopter."
posted by dhartung at 3:08 PM on March 25, 2008

I was taught that in a forward taxi attitude the front rotor of a CH-47, Chinook, is about 4 feet above the ground. The rotor of the Bell Jet Ranger/Huey group, 204...214, can dip to one side if hit by an unexpected side wind while they're shutting down. The guidance we got was to exit directly away from the side of the Bells and the Hughes 500 and to always stay well clear of the tail rotor area. And reflexively I almost always always crouched or ducked when exiting after landing anywhere other than an airfield.

I was present at the scene of an incident where a UH-1 with battle damage made a hard landing at Cu Chi. As one of the flight crew was evacuating, the skid on his side of the ship collapsed and he was struck and killed by the rotor. It's an awful memory. Don't know if ducking would have made any difference in his case.
posted by X4ster at 3:43 PM on March 25, 2008

USFS Firefighters are trained to duck when approaching or exiting helicopters. We always boarded wearing full gear, with leather gloves, long sleeves buttoned, hard hats on, etc, while ducking down. I'm pretty short and wasn't exempt.

Ditto for Search and Rescue training- our heli-rap crew always boarded the aircraft ducking.

A few times I've been on fires as the helicopter was arriving or departing, or we were getting out, or they were doing bucket drops- it seems like the tuck in addition to being instinctive is also sort of common sense. There is often small debris flying through the air, better it strike the hard hat than your face.
posted by arnicae at 6:59 PM on March 25, 2008