a VERY close call....who'd be deck crew? [Archive]

JohnO

February 20th 07, 07:04 PM

On Feb 21, 5:13 am, "Andrew Crane" > wrote:
> "Nick" > wrote in message
>
> ...
>
> > Thought you guys might be interested
>
> >http://www.videosift.com/video/Helicopter-Madness-A-Close-Call
>
> > But why wouldn't he have kept some negative collective to keep it nailed
> to
> > the deck?.... how far would the tips 'dished' down?.....not enough to
> cause
> > the crew more worries than they already had??
>
> I think you dreamed "negative collective".
>
> > It seemed very light on the skids on the previous couple of swells??
>
> The chap took off. It didn't do this by itself.
>
> Regards
> Andrew

If the collective was not full down the chopper would be light on the
skids, The ship dropping in the swell would be enough for it to lift
off the deck.

Don W

February 20th 07, 10:32 PM

Nick wrote:
> Thought you guys might be interested
>
> http://www.videosift.com/video/Helicopter-Madness-A-Close-Call
>
> But why wouldn't he have kept some negative collective to keep it nailed to
> the deck?.... how far would the tips 'dished' down?.....not enough to cause
> the crew more worries than they already had??
>
> It seemed very light on the skids on the previous couple of swells??

Wow! He was lucky to get it back down on the deck
in one piece with no tail rotor. It could have
just as easily easily gone over the side.

That video is a good lesson on why hot shots get
in trouble sometimes.

Don W.

Elzee36

February 21st 07, 02:57 PM

On Feb 20, 5:32ï¿½pm, Don W >
wrote:

> Wow! *He was lucky to get it back down on the deck
> in one piece with no tail rotor.

No the lucky one is the ground crew guy who was in the rear when the
copter started
to spin. Whoa!!

Don W

February 21st 07, 07:03 PM

Elzee36 wrote:
> On Feb 20, 5:32ï¿½pm, Don W >
> wrote:
>
>
>>Wow! ?He was lucky to get it back down on the deck
>>in one piece with no tail rotor.
>
>
> No the lucky one is the ground crew guy who was in the rear when the
> copter started
> to spin. Whoa!!

Yes, He was lucky too.

Don W.

Andrew Crane

February 22nd 07, 03:25 PM

"JohnO" > wrote in message
oups.com...
> On Feb 21, 5:13 am, "Andrew Crane" > wrote:
> > "Nick" > wrote in message
> >
> > ...
> >
> > > Thought you guys might be interested
> >
> > >http://www.videosift.com/video/Helicopter-Madness-A-Close-Call
> >
> > > But why wouldn't he have kept some negative collective to keep it
nailed
> > to
> > > the deck?.... how far would the tips 'dished' down?.....not enough to
> > cause
> > > the crew more worries than they already had??
> >
> > I think you dreamed "negative collective".
> >
> > > It seemed very light on the skids on the previous couple of swells??
> >
> > The chap took off. It didn't do this by itself.
> >
> > Regards
> > Andrew
>
> If the collective was not full down the chopper would be light on the
> skids, The ship dropping in the swell would be enough for it to lift
> off the deck.

Which begs the question why was he light on the skids in the first place.
And why he didn't respond to the lurching during the previous two swells. I
think he was having a play.

Regards
Andrew

JohnO

February 22nd 07, 09:41 PM

On Feb 23, 4:25 am, "Andrew Crane" > wrote:
> "JohnO" > wrote in message
>
> oups.com...
>
>
>
>
>
> > On Feb 21, 5:13 am, "Andrew Crane" > wrote:
> > > "Nick" > wrote in message
>
> > ...
>
> > > > Thought you guys might be interested
>
> > > >http://www.videosift.com/video/Helicopter-Madness-A-Close-Call
>
> > > > But why wouldn't he have kept some negative collective to keep it
> nailed
> > > to
> > > > the deck?.... how far would the tips 'dished' down?.....not enough to
> > > cause
> > > > the crew more worries than they already had??
>
> > > I think you dreamed "negative collective".
>
> > > > It seemed very light on the skids on the previous couple of swells??
>
> > > The chap took off. It didn't do this by itself.
>
> > > Regards
> > > Andrew
>
> > If the collective was not full down the chopper would be light on the
> > skids, The ship dropping in the swell would be enough for it to lift
> > off the deck.
>
> Which begs the question why was he light on the skids in the first place.
> And why he didn't respond to the lurching during the previous two swells. I
> think he was having a play.
>
> Regards
> Andrew- Hide quoted text -
>
> - Show quoted text -

That or incredibly careless given the situation. Either way, pretty
inexcusable.

Very nice job of instantly dumping collective to get back down after
the tail strike. Any attempt to fly it down and he'd have been history.

Steve R

February 23rd 07, 07:26 AM

"JohnO" > wrote in message
oups.com...
> On Feb 23, 4:25 am, "Andrew Crane" > wrote:
>> "JohnO" > wrote in message
>>
>> oups.com...
>>
>>
>>
>>
>>
>> > On Feb 21, 5:13 am, "Andrew Crane" > wrote:
>> > > "Nick" > wrote in message
>>
>> > ...
>>
>> > > > Thought you guys might be interested
>>
>> > > >http://www.videosift.com/video/Helicopter-Madness-A-Close-Call
>>
>> > > > But why wouldn't he have kept some negative collective to keep it
>> nailed
>> > > to
>> > > > the deck?.... how far would the tips 'dished' down?.....not enough
>> > > > to
>> > > cause
>> > > > the crew more worries than they already had??
>>
>> > > I think you dreamed "negative collective".
>>
>> > > > It seemed very light on the skids on the previous couple of
>> > > > swells??
>>
>> > > The chap took off. It didn't do this by itself.
>>
>> > > Regards
>> > > Andrew
>>
>> > If the collective was not full down the chopper would be light on the
>> > skids, The ship dropping in the swell would be enough for it to lift
>> > off the deck.
>>
>> Which begs the question why was he light on the skids in the first place.
>> And why he didn't respond to the lurching during the previous two swells.
>> I
>> think he was having a play.
>>
>> Regards
>> Andrew- Hide quoted text -
>>
>> - Show quoted text -
>
> That or incredibly careless given the situation. Either way, pretty
> inexcusable.
>
> Very nice job of instantly dumping collective to get back down after
> the tail strike. Any attempt to fly it down and he'd have been history.
>

Is the netting standard equipment in such cases? Seem like it did a good
job of giving the skids something to grab on to when he set it down. I can
imagine the aircraft sliding off the pad without it.

Also, those have "got" to be two of the luckiest deck hands in the world!

Fly Safe,
Steve R.

B4RT

February 23rd 07, 11:31 PM

"Nick" > wrote in message
...
> Thought you guys might be interested
>
> http://www.videosift.com/video/Helicopter-Madness-A-Close-Call
>
> But why wouldn't he have kept some negative collective to keep it nailed
> to the deck?.... how far would the tips 'dished' down?.....not enough to
> cause the crew more worries than they already had??
>
> It seemed very light on the skids on the previous couple of swells??
>

Negative collective? .....ROTFLMFAO! Boy I dont think I have that option on
mine.

My armchair analysis is that the helicopter appeared to have a forward CG
and the deck was pitching as much as 15 degrees and rolling about 7 or 8. I
don't think the pilot really ever "wanted" to take off. It looked to me like
the deck pitched forward a whole lot and he thought the helicopter would
nose over if he didn't take off. The deck angle was pitched very far
forward at the moment of the tail strike, and the camera gives the illusion
that the helicopter was at far less level pitch that it was.

I'm thinking that the pilot was taking the lesser of two evils and got bit
by one of them. Its clear to me that he was pretty skilled because doing a
totally successful hovering auto to that platform like that couldn't be done
by an unskilled pilot. The only bad piloting in this incident appears to
have happened way before the engine started when someone decided that it was
ok to take off in seas like that.

Bart

JohnO

February 24th 07, 08:32 AM

On Feb 24, 12:31 pm, "B4RT" > wrote:
> "Nick" > wrote in message
>
> ...
>
> > Thought you guys might be interested
>
> >http://www.videosift.com/video/Helicopter-Madness-A-Close-Call
>
> > But why wouldn't he have kept some negative collective to keep it nailed
> > to the deck?.... how far would the tips 'dished' down?.....not enough to
> > cause the crew more worries than they already had??
>
> > It seemed very light on the skids on the previous couple of swells??
>
> Negative collective? .....ROTFLMFAO! Boy I dont think I have that option on
> mine.

Heh! The only heli's I've seen that can do negative are the R/C ones -
they can fly upside down!

>
> My armchair analysis is that the helicopter appeared to have a forward CG
> and the deck was pitching as much as 15 degrees and rolling about 7 or 8. I
> don't think the pilot really ever "wanted" to take off. It looked to me like
> the deck pitched forward a whole lot and he thought the helicopter would
> nose over if he didn't take off. The deck angle was pitched very far
> forward at the moment of the tail strike, and the camera gives the illusion
> that the helicopter was at far less level pitch that it was.
>
> I'm thinking that the pilot was taking the lesser of two evils and got bit
> by one of them. Its clear to me that he was pretty skilled because doing a
> totally successful hovering auto to that platform like that couldn't be done
> by an unskilled pilot. The only bad piloting in this incident appears to
> have happened way before the engine started when someone decided that it was
> ok to take off in seas like that.
>
> Bart

JohnO

February 24th 07, 08:35 AM

On Feb 24, 12:31 pm, "B4RT" > wrote:
> "Nick" > wrote in message
>
> ...
>
> > Thought you guys might be interested
>
> >http://www.videosift.com/video/Helicopter-Madness-A-Close-Call
>
> > But why wouldn't he have kept some negative collective to keep it nailed
> > to the deck?.... how far would the tips 'dished' down?.....not enough to
> > cause the crew more worries than they already had??
>
> > It seemed very light on the skids on the previous couple of swells??
>
> Negative collective? .....ROTFLMFAO! Boy I dont think I have that option on
> mine.
>
> My armchair analysis is that the helicopter appeared to have a forward CG

Why would that be?

> and the deck was pitching as much as 15 degrees and rolling about 7 or 8. I
> don't think the pilot really ever "wanted" to take off. It looked to me like
> the deck pitched forward a whole lot and he thought the helicopter would
> nose over if he didn't take off. The deck angle was pitched very far

I don't think the problem was the angle of the deck - more that it's
acceleration down cancelled some gravity - a little POSITIVE
collective could have been enough to lift off. Seems like he had a lot
of forward cyclic as well though.
> forward at the moment of the tail strike, and the camera gives the illusion
> that the helicopter was at far less level pitch that it was.
>
> I'm thinking that the pilot was taking the lesser of two evils and got bit
> by one of them. Its clear to me that he was pretty skilled because doing a
> totally successful hovering auto to that platform like that couldn't be done
> by an unskilled pilot. The only bad piloting in this incident appears to
> have happened way before the engine started when someone decided that it was
> ok to take off in seas like that.
>
> Bart

B4RT

February 24th 07, 01:13 PM

"JohnO" > wrote in message
s.com...

>> My armchair analysis is that the helicopter appeared to have a forward CG
>
> Why would that be?
>
I dont know, maybe there were two fattys on board with the pilot. I've flown
an Enstrom and don't recall it being nose heavy, but each time the ship
pitched forward I thought I noticed it get light on the aft section of the
skids.

>> and the deck was pitching as much as 15 degrees and rolling about 7 or 8.
>> I
>> don't think the pilot really ever "wanted" to take off. It looked to me
>> like
>> the deck pitched forward a whole lot and he thought the helicopter would
>> nose over if he didn't take off. The deck angle was pitched very far
>
> I don't think the problem was the angle of the deck - more that it's
> acceleration down cancelled some gravity - a little POSITIVE
> collective could have been enough to lift off. Seems like he had a lot
> of forward cyclic as well though.

Nah... I don't think so. Boats dont go up and down in seas like that with
negative G's that significant. Enstrom pilots don't tend to spend a lot of
time getting light on the skids either because of the damn oleo struts and
ground resonance tendancy of that machine. That guy flying was no amateur,
he was locked and loaded when he chopped the throttle and did that auto.

There's several HUGE differences in the flight dynamics of RC heli's and
real ones. RC's tend to have very low CG's, this makes them more stable.
RC's have an assload more collective juice than the big things, you don't
come off the helipad in a real one without really intending to do it. The
static and dynamic relative rotor mass of a an RC is very small, you can
move the cyclic much more quickly in an RC and have it take effect without
lag. The big spinny gyrosope thingy on top doesnt wan't to change that
quickly on a big helicopter. These differences can make it hard to
extrapolate the operation of a big one from experiences with a small one.
Just imagine trying to drive a semi truck in the same manner you'd drive a
Porche.

Bart

Nick

February 24th 07, 03:15 PM

> Negative collective? .....ROTFLMFAO! Boy I dont think I have that option
> on mine.

What is the pitch range on this helicopter?......anyone?......I 'fly' RC,
but it'd be interesting to know that negative pitch as not possible.....does
that go for all full size helis?

So the fact that the machine appeared light on its skids could not have been
corrected?....or minimised?

"B4RT" > wrote in message
...
>
> "Nick" > wrote in message
> ...
>> Thought you guys might be interested
>>
>> http://www.videosift.com/video/Helicopter-Madness-A-Close-Call
>>
>> But why wouldn't he have kept some negative collective to keep it nailed
>> to the deck?.... how far would the tips 'dished' down?.....not enough to
>> cause the crew more worries than they already had??
>>
>> It seemed very light on the skids on the previous couple of swells??
>>
>
> Negative collective? .....ROTFLMFAO! Boy I dont think I have that option
> on mine.
>
> My armchair analysis is that the helicopter appeared to have a forward CG
> and the deck was pitching as much as 15 degrees and rolling about 7 or 8.
> I don't think the pilot really ever "wanted" to take off. It looked to me
> like the deck pitched forward a whole lot and he thought the helicopter
> would nose over if he didn't take off. The deck angle was pitched very
> far forward at the moment of the tail strike, and the camera gives the
> illusion that the helicopter was at far less level pitch that it was.
>
> I'm thinking that the pilot was taking the lesser of two evils and got bit
> by one of them. Its clear to me that he was pretty skilled because doing a
> totally successful hovering auto to that platform like that couldn't be
> done by an unskilled pilot. The only bad piloting in this incident appears
> to have happened way before the engine started when someone decided that
> it was ok to take off in seas like that.
>
> Bart
>

JohnO

February 24th 07, 07:54 PM

On Feb 25, 2:13 am, "B4RT" > wrote:
> "JohnO" > wrote in message
>
> s.com...
>
> >> My armchair analysis is that the helicopter appeared to have a forward CG
>
> > Why would that be?
>
> I dont know, maybe there were two fattys on board with the pilot. I've flown
> an Enstrom and don't recall it being nose heavy, but each time the ship
> pitched forward I thought I noticed it get light on the aft section of the
> skids.
>
> >> and the deck was pitching as much as 15 degrees and rolling about 7 or 8.
> >> I
> >> don't think the pilot really ever "wanted" to take off. It looked to me
> >> like
> >> the deck pitched forward a whole lot and he thought the helicopter would
> >> nose over if he didn't take off. The deck angle was pitched very far
>
> > I don't think the problem was the angle of the deck - more that it's
> > acceleration down cancelled some gravity - a little POSITIVE
> > collective could have been enough to lift off. Seems like he had a lot
> > of forward cyclic as well though.
>
> Nah... I don't think so. Boats dont go up and down in seas like that with
> negative G's that significant.

Definitely not true. Ever watch thet tv show 'Deadliest Catch' where
they embed a camera guys on crab boats in the Bering Sea? One of the
things they do to pass the time between getting cold and wet is to
jump up just as the boat plunges into a swell. They float like
astronauts for a moment. I've never done that but have certainly been
on the deck of a boat many times and felt very much unweighted as the
boat plunges into a trough. I assume it would be normal practice for a
vessel to steam into the wind when carrying out aircraft operations
and this gives the fastest drops into the swell.

> Enstrom pilots don't tend to spend a lot of
> time getting light on the skids either because of the damn oleo struts and
> ground resonance tendancy of that machine. That guy flying was no amateur,
> he was locked and loaded when he chopped the throttle and did that auto.

He sure did that beautifully. But even pros sometimes get sloppy for a
moment on rare occasions. It's not out of the question that he slipped
up, but then his training and experience snapped in to save the day.

>
> There's several HUGE differences in the flight dynamics of RC heli's and
> real ones. RC's tend to have very low CG's, this makes them more stable.
> RC's have an assload more collective juice than the big things, you don't
> come off the helipad in a real one without really intending to do it. The
> static and dynamic relative rotor mass of a an RC is very small, you can
> move the cyclic much more quickly in an RC and have it take effect without
> lag. The big spinny gyrosope thingy on top doesnt wan't to change that
> quickly on a big helicopter. These differences can make it hard to
> extrapolate the operation of a big one from experiences with a small one.
> Just imagine trying to drive a semi truck in the same manner you'd drive a
> Porche.
>
> Bart

Steve L.[_3_]

February 24th 07, 11:06 PM

>> Negative collective? .....ROTFLMFAO! Boy I dont think I have that option
>> on mine.
>
>What is the pitch range on this helicopter?......anyone?......I 'fly' RC,
>but it'd be interesting to know that negative pitch as not possible.....does
>that go for all full size helis?

I know of only one big helicopter that ever had negative pitch (-3°). It
is a military American one; can't recall the type.
The reason for that is that it should be able to do a very quick
vertical descent while hovering just over tree tops.

For all other helicopters it were pretty useless but would cost a lot
because the control rigging would need far more travel.

There is no civilian helo with negative pitch, not even 0°. The minimum
pitch might be as high as +4°.

Nick

February 25th 07, 09:40 AM

"Steve L." > wrote in message
...
>>> Negative collective? .....ROTFLMFAO! Boy I dont think I have that
>>> option
>>> on mine.
>>
>>What is the pitch range on this helicopter?......anyone?......I 'fly' RC,
>>but it'd be interesting to know that negative pitch as not
>>possible.....does
>>that go for all full size helis?
>
> I know of only one big helicopter that ever had negative pitch (-3°). It
> is a military American one; can't recall the type.
> The reason for that is that it should be able to do a very quick
> vertical descent while hovering just over tree tops.
>
> For all other helicopters it were pretty useless but would cost a lot
> because the control rigging would need far more travel.
>
> There is no civilian helo with negative pitch, not even 0°. The minimum
> pitch might be as high as +4°.
>
Thanks for the reply. But what happens during autorotation to keep the
headspeed up? ......headspeed will surely decay very quickly at +4degrees?

Steve R

February 25th 07, 02:09 PM

"Nick" > wrote in message
...
>
> "Steve L." > wrote in message
> ...
>>>> Negative collective? .....ROTFLMFAO! Boy I dont think I have that
>>>> option
>>>> on mine.
>>>
>>>What is the pitch range on this helicopter?......anyone?......I 'fly' RC,
>>>but it'd be interesting to know that negative pitch as not
>>>possible.....does
>>>that go for all full size helis?
>>
>> I know of only one big helicopter that ever had negative pitch (-3°). It
>> is a military American one; can't recall the type.
>> The reason for that is that it should be able to do a very quick
>> vertical descent while hovering just over tree tops.
>>
>> For all other helicopters it were pretty useless but would cost a lot
>> because the control rigging would need far more travel.
>>
>> There is no civilian helo with negative pitch, not even 0°. The minimum
>> pitch might be as high as +4°.
>>
> Thanks for the reply. But what happens during autorotation to keep the
> headspeed up? ......headspeed will surely decay very quickly at +4degrees?

I fly RC helicopters too and have "very" limited experience in the full size
counterparts. What most RCer's don't understand is that you don't need
negative pitch to autorotate. What RCer's refer to as "negative" collective
is simply an measurement of blade incidence. It has nothing to do with the
rotor blades aerodynamic angle of attack (AOA). Nick, even if you're
running your model with a -5 at full down setup, the blades are still flying
a positive AOA in the auto at that setting. Granted, it'll be dropping like
a rock in that mode but the blades are still seeing a positive AOA. I've
played around with autos on my RC birds and, with a bit of a breeze, have
made sustained autorotative approaches and a safe landing with the
collective as high as +3 degrees. Granted, I wasn't carrying a lot of rotor
rpm on the descent so the collective "pull" at the bottom was a bit critical
but it's definitely doable.

The full size birds, as Steve L pointed out, rarely if ever go into the
negative incidence range. First, because the simply don't need to and more
importantly, because they are "much" more critical about maintaining a
specific rotor rpm. If they dropped into a negatie incidence range, they'd
overspeed the rotor with obvious results. The big guys simply can't stand
the rpm swings that our models do in their stride.

FWIW!
Fly Safe,
Steve R.

B4RT

February 28th 07, 06:15 PM

I didn't measure it, but from the look of it the blade pitch at the tip of
the main rotor of my jetranger when its at 90 degrees to the right (the
most negative pitch point) and the collective full down is roughly 0
degrees, it might even be a shade negative.

Bart

"The OTHER Kevin in San Diego" <skiddz "AT" adelphia "DOT" net> wrote in
message ...
> On Sat, 24 Feb 2007 15:06:40 -0800, Steve L. > wrote:
>
>
>>I know of only one big helicopter that ever had negative pitch (-3°). It
>>is a military American one; can't recall the type.
>>The reason for that is that it should be able to do a very quick
>>vertical descent while hovering just over tree tops.
>
> A&P buddy of mine who was in the Marines told me the CH-53 can do
> about -3 degrees collective. Not sure of the reasoning behind it..
>
>>For all other helicopters it were pretty useless but would cost a lot
>>because the control rigging would need far more travel.
>>
>>There is no civilian helo with negative pitch, not even 0°. The minimum
>>pitch might be as high as +4°.
>
> The negative twist in the blades might get parts of the blade into
> negative pitch in an auto (or even a rapid power descent) but I don't
> know if the AoA ever goes negative...
>

Don W

February 28th 07, 06:59 PM

B4RT wrote:
> I didn't measure it, but from the look of it the blade pitch at the tip of
> the main rotor of my jetranger when its at 90 degrees to the right (the
> most negative pitch point) and the collective full down is roughly 0
> degrees, it might even be a shade negative.

Was that with the cyclic neutral? If so, it would
be interesting to have someone in the ship apply
full down collective and full back cyclic while
you looked at it.

Don W.

B4RT

March 5th 07, 11:04 PM

"The OTHER Kevin in San Diego" <skiddz "AT" adelphia "DOT" net> wrote in
message ...
> On Wed, 28 Feb 2007 13:15:15 -0500, "B4RT" >
> wrote:
>
>>I didn't measure it, but from the look of it the blade pitch at the tip of
>>the main rotor of my jetranger when its at 90 degrees to the right (the
>>most negative pitch point) and the collective full down is roughly 0
>>degrees, it might even be a shade negative.
>
> Hey Bart,
>
> Any idea where I can get my hands on an old Bell 206 collective
> assembly? Specifically the collective lever and end "box"...
> Preferrably something that's been removed from service and is of no
> use to anyone any longer..

I don't really know.

It would probably be easier to find a Huey collective, its not a life
limited part on the Jetranger so the only place to find one would be a
boneyard. Surplus military parts are all over from what I hear.

Bart

Bob Upp

March 14th 07, 06:15 AM

I am no expert but I am amazed at some of the most obvious cause and
effect completely ignored by every comment so far.
First thought: This pilot had no collective obviously apparent.
Second: ETL is present even in a helicopter with flat pitch, especially
in this open water situation, not counting any forward velocity of the
ship itself
Third: Yes a whole bunch of full size helicopters technically have some
negative pitch, collective down on twisted blades typically have
negative pitch at the tips.

A casual observer might see a pitching deck, a gusting wind, less than
full load and a pilot not certain if the helicopter is fully released
for departure. Its just a thought but the pilot may not have lifted off
intentionally. In fact No professional pilot would have committed a
deliberate departure not knowing the status of the crewman that just ran
to the rear of the helicopter to perform a task.

"Nick" > wrote in message
...
>> Negative collective? .....ROTFLMFAO! Boy I dont think I have that
>> option on mine.
>
> What is the pitch range on this helicopter?......anyone?......I 'fly'
> RC, but it'd be interesting to know that negative pitch as not
> possible.....does that go for all full size helis?
>
> So the fact that the machine appeared light on its skids could not
> have been corrected?....or minimised?
>
>
> "B4RT" > wrote in message
> ...
>>
>> "Nick" > wrote in message
>> ...
>>> Thought you guys might be interested
>>>
>>> http://www.videosift.com/video/Helicopter-Madness-A-Close-Call
>>>
>>> But why wouldn't he have kept some negative collective to keep it
>>> nailed to the deck?.... how far would the tips 'dished'
>>> down?.....not enough to cause the crew more worries than they
>>> already had??
>>>
>>> It seemed very light on the skids on the previous couple of swells??
>>>
>>
>> Negative collective? .....ROTFLMFAO! Boy I dont think I have that
>> option on mine.
>>
>> My armchair analysis is that the helicopter appeared to have a
>> forward CG and the deck was pitching as much as 15 degrees and
>> rolling about 7 or 8. I don't think the pilot really ever "wanted" to
>> take off. It looked to me like the deck pitched forward a whole lot
>> and he thought the helicopter would nose over if he didn't take off.
>> The deck angle was pitched very far forward at the moment of the tail
>> strike, and the camera gives the illusion that the helicopter was at
>> far less level pitch that it was.
>>
>> I'm thinking that the pilot was taking the lesser of two evils and
>> got bit by one of them. Its clear to me that he was pretty skilled
>> because doing a totally successful hovering auto to that platform
>> like that couldn't be done by an unskilled pilot. The only bad
>> piloting in this incident appears to have happened way before the
>> engine started when someone decided that it was ok to take off in
>> seas like that.
>>
>> Bart
>>
>
>
>

Arvin THd.

March 15th 07, 02:12 AM

Clark > wrote in
:

> "Steve R" > wrote in
> :
>
>> "JohnO" > wrote in message
>> oups.com...
>>> On Feb 23, 4:25 am, "Andrew Crane" > wrote:
>>>> "JohnO" > wrote in message
>>>>
>>>> oups.com...
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> > On Feb 21, 5:13 am, "Andrew Crane" > wrote:
>>>> > > "Nick" > wrote in message
>>>>
>>>> > ...
>>>>
>>>> > > > Thought you guys might be interested
>>>>
>>>> > > >http://www.videosift.com/video/Helicopter-Madness-A-Close-Call
>>>>
>>>> > > > But why wouldn't he have kept some negative collective to
>>>> > > > keep it
>>>> nailed
>>>> > > to
>>>> > > > the deck?.... how far would the tips 'dished' down?.....not
>>>> > > > enough to
>>>> > > cause
>>>> > > > the crew more worries than they already had??
>>>>
>>>> > > I think you dreamed "negative collective".
>>>>
>>>> > > > It seemed very light on the skids on the previous couple of
>>>> > > > swells??
>>>>
>>>> > > The chap took off. It didn't do this by itself.
>>>>
>>>> > > Regards
>>>> > > Andrew
>>>>
>>>> > If the collective was not full down the chopper would be light on
>>>> > the skids, The ship dropping in the swell would be enough for it
>>>> > to lift off the deck.
>>>>
>>>> Which begs the question why was he light on the skids in the first
>>>> place. And why he didn't respond to the lurching during the
>>>> previous two swells. I
>>>> think he was having a play.
>>>>
>>>> Regards
>>>> Andrew- Hide quoted text -
>>>>
>>>> - Show quoted text -
>>>
>>> That or incredibly careless given the situation. Either way, pretty
>>> inexcusable.
>>>
>>> Very nice job of instantly dumping collective to get back down after
>>> the tail strike. Any attempt to fly it down and he'd have been
>>> history.
>>>
>>
>> Is the netting standard equipment in such cases? Seem like it did a
>> good job of giving the skids something to grab on to when he set it
>> down. I can imagine the aircraft sliding off the pad without it.
>>
>> Also, those have "got" to be two of the luckiest deck hands in the
>> world!
>>
> From an observers (non-pilot) point of view, netting seems to be
> standard for North Sea operations. I think it's required by the rules
> for offshore oilfield operations but it's been too long since I had to
> deal with that sort of stuff to be sure that my memory of the
> requirement is correct.

Whether netting is required on NS decks depends on the friction of the
un-netted deck. If the friction of the deck without netting is sufficient
then none is required.

Having said that, it is generally preferable to have netting since it
aids grip and it can aid visual cuing during the last few feet of an
approach.

Arvin.