Ducking under helicopter blades - why?

[jhfozzy]

mikal83 said:

illmonkey said:

So why not start it when everyone is on board. I'm sure there is a reasonable explanation!

IF there should be an emergency, say a fire.......

This, I only really have experience of Lynx and Gazelle (Ex-REME), but there is a lot involved in starting them up, including a tech climbing up the side of the helicopter whilst its burning and turning to peer into little ports to check for fire in the engines, making sure there's no undue vibration from the gearboxes and drivetrain, etc.

We only then allow the passengers to embark.

[CB2152]

Example of solving ground resonance. This is during the opening sequence of an episode of "Macgyver".

http://youtu.be/6vICf8l-KV0

[tuffer]

I was in Croatia in about 94/95 and some Army types disembarked a Lynx, a WRAC ran into the tail rotor......End of.

[RobbyJ]

I've always ducked a bit personally. Would you stand with your toes touching the edge of the train platform when it's coming past at 100mph? You most likely won't get hit by the train but why risk your life. Just duck a bit under rotor blades and reduce the risk. The OP mentioned Chinooks, have you seen how low the blades are to the ground at the front of the aircraft. You approach one of these from the front when the blades are moving slowly in anything other than a full limbo then you're getting chopped in half!

[Super Slo Mo]

illmonkey said:

Clearly you are! (I suppose me too...)

Yes yes, lots of things do. It can't be nice for any involved, and to save 30 seconds it seemed a fair option.

It takes quite a lot longer than 30 seconds for a turbine helicopter, although you make a valid point.
There are plenty of situations though where it's not really feasible to shut down while a person or people are alongside. I've had to stand beside a heli trying to fix a sodding camera attached to it, while the engines were running, as the fault only became apparent on start up and would disappear when the engines shut off.

I've also been involved in situations where we had to load people on board when the aircraft was running, it's safe enough if the proper procedures are followed, and the aircraft we were using didn't have massive blade sag. The procedures are in place to mitigate the risk as much as possible, and generally accidents only happen when people fail to adhere to the procedures.

Approaching from the rear is generally a no-no, as firstly the pilot can't see you and he might think it's clear to take off, and you definitely don't want to be alongside when that happens, in case the tail needs to come around. The other problem with approaching from the rear is the tail rotor, which is invisible at normal rotating speeds.

Personally I wouldn't go near the darned things if I could possibly avoid it, they're fairly intimidating to be up close to, and the percussion effects on your body when standing right next to a fully powered up aircraft have to be experienced to be believed.

So yes, you make a valid point, but unfortunately, it's not always feasible to have the engines off. To be fair, it's probably not a great deal more dangerous than actually flying in one anyway.

[pete]

I used to fly on an S61N on a regular basis to and from St Mary's in the Isles of Scilly. I don't remember ever boarding or disembarking *without* the rotors turning; as stated previously, I watched the startup process many times and it looked pretty involved.

Even with the vast size of an S61 (think Sea King if you've never seen one) I always found myself ducking while in the queue to board due to the noise, percussive effects, and heat from the exhausts. It was just a plain unpleasant environment to spend any time wandering around surveying the scenery, and that's from a die hard aero geek!

Pete

[Hainey]

The more times I have to start it, the more chance I have of a 'hot start'. Thats 60k per engine per feck up.

You lot can stick to getting in when she's running!

[soad]

Made me think of The Sopranos!



Tony, Furio, and other members of the crew visit a Native American-owned casino in Connecticut. While most of the others carouse, Furio stands aloof. Later, as the drunken crew prepares to board the casino's helicopter for the flight home, Furio grabs Tony by the shirt front and appears barely able to restrain himself from shoving Tony into the spinning tail rotor. Furio tells the baffled Tony he was standing too close to the blades.

[wokkadriver]

Hainey said:

The ducking thing is something I always brief any pax about. That and never, ever approach from the rear, always the front. Those are my two golden rules at the pre flight briefing.

Except in a chinook. The front is a bad thing….

[wokkadriver]

Hainey said:

The ducking thing is something I always brief any pax about. That and never, ever approach from the rear, always the front. Those are my two golden rules at the pre flight briefing.

Except in a chinook. The front is a bad thing….

[Ilovejapcrap]

P-Jay said:

when I'm getting on a chopper

Is it Saturday already

[kev b]

Does anyone else remember a while back, 20 yrs or more iirc, a wealthy bloke arrived home by helicopter, his wife and young child were awaiting his arrival.

The youngster ran to her dad and he swept her up straight into the rotors, my children were the same age at the time and my blood still runs cold thinking about it.

[Rich_W]

iambeowulf said:

I remember when Noel Edmunds used to fly around in his helicopter when he lived in Buckinghamshire.
I often imagined him getting his head chopped off. (Not Mr Blobby's though)

Sadly he's still annoying us.

He's worse than annoying!

https://www.youtube.com/watch?v=EGtdsXhXiEM

[Vipers]

wokkadriver said:

Hainey said:

The ducking thing is something I always brief any pax about. That and never, ever approach from the rear, always the front. Those are my two golden rules at the pre flight briefing.

Except in a chinook. The front is a bad thing….

Always told you approached towards the door, not the front, especially an S76, that's the one took the HLO's head off on the DSV Mayo I believe.

Edited by Vipers on Friday 3rd April 16:48

[Testaburger]

P-Jay said:

What a brilliant picture!

[Mave]

Vipers said:

Always told you approached towards the door, not the front, especially an S76, that's the one took the HLO's head off on the DSV Mayo I believe.

Edited by Vipers on Friday 3rd April 16:48

Out of interest, why not the front? Is that because if the pilot hadn't spotted you and was taking off he'd dip the front of the rotor circle downwards to accelerate? Assuming he landed into wind, would wind gusts make the rotors lift more at the front than the sides?

[Vipers]

H

Mave said:

Vipers said:

Always told you approached towards the door, not the front, especially an S76, that's the one took the HLO's head off on the DSV Mayo I believe.

Edited by Vipers on Friday 3rd April 16:48

Out of interest, why not the front? Is that because if the pilot hadn't spotted you and was taking off he'd dip the front of the rotor circle downwards to accelerate? Assuming he landed into wind, would wind gusts make the rotors lift more at the front than the sides?

I have absolutely no idea, I was only the passenger. But on the S76 which the disc is low in front anyway I think, if the vessel dips, although the angle of the deck and chopper changes, the disc remains in the same plane, resulting in the distance from disc to deck decreases.

Then again I could be talking out of my backside.

http://www.alpineheliski.com/resources/file/helico...

Then again

http://www.careflite.org/cfimg/landingzone/lz-3.gi...

Maybe different choppers have different approach procedures.

Edited by Vipers on Friday 3rd April 20:34

Edited by Vipers on Friday 3rd April 20:37

Edited by Vipers on Friday 3rd April 20:41

[Mave]

Vipers said:

I have absolutely no idea, I was only the passenger. But on the S76 which the disc is low in front anyway I think, if the vessel dips, although the angle of the deck and chopper changes, the disc remains in the same plane, resulting in the distance from disc to deck decreases.

Then again I could be talking out of my backside.

http://www.alpineheliski.com/resources/file/helico...

Then again

http://www.careflite.org/cfimg/landingzone/lz-3.gi...

Maybe different choppers have different approach procedures.

Edited by Vipers on Friday 3rd April 20:34

Edited by Vipers on Friday 3rd April 20:37

Edited by Vipers on Friday 3rd April 20:41

See, that safety briefing makes sense to me, in that the rotor should be horizontal when the helicopter is just sitting on the ground- and if the pilot has landed / is taking off into wind, then gusts will cause the rotor to dip at the back, rather than the front...

[HD Adam]

Here's a good video of an S76 starting up and idling.

https://www.youtube.com/watch?v=AQ0oSGlT0so

See how the rotor is angled downwards towards the front?

I've had to grab people a few times who were oblivious to this and started to wander towards the blades.

[Mave]

Good video, thanks.
Any idea why it's set up like that? Reduce ground resonance by putting a bit of forward load on the helicopter? Is that actually the "neutral" point on the cyclic, so you get more total range in the forward direction than the rear? I guess a high speed helicopter is limited by the articulation of the hinges, so maybe they're biased towards forwards flight? I couldn't see from the film, is the rotor shaft inclined forward?