Pa. Medevac chopper crash--inverted in flight?

[pavulon]

How does a helicopter become unintentionally inverted in flight? Does a tail rotor driveshaft failure cause that? How does that scenario happen and still allow time for crew to secure themselves and a patient before hitting the ground?

https://www.heraldmailmedia.com/story/news/local/2022/02/04/medevac-helicopter-crash-hagerstown-md-chambersburg-pa-philadelphia/6662578001/

[Seahawk]

Not enough to go on, at least for me. Here is a good overview of the EC 135:

https://www.flyingmag.com/aircraft-helicopters-eurocopter-ec-135/

There is evidentially a door bell camera video.

[svandamme]

could some kind of swashplate linkage failure do that? inadvertant roll and loss of control?
Then cut out most power, so it no longer pulls in the wrong direction, but hard landing as a result of that ??

[Bill Douglas]

Great skills getting it under control and being able to choose a place to land.

[svandamme]

Suspect he had little choice in location and the thing came down where it came down, when it came down and at best had some ability to control attitude, not altitude and/or direction..

think of it this way.. choose between lift or attitude,
because if you increase lift the thing rolls again.. that kind of a deal..

similar issues have happened with fixed wing when certain controls drop out or freeze up.
can't go slow because then suddenly the lack of airflow makes the control problems worse.

And I would guess a helicopter, while very different from fixed plane.. can have similar conflict when anything in the linkage disconnects or locks up.
Especially since the lift and cyclic control it's all connected to the rotor blades.. In effect it's all combining through the swashplate and linkages.. so when that fails, your lift, roll, pitch , it's all directly connected to the failed piece.

which on a fixed wing plane would not be the case.. lift is wings, roll is ailerons, pitch is elevators, yaw is rudder They are all seperate devices.

[rusnak]

^ which is why helicopters tend to rotate when they're going to crash.

[svandamme]

I would think, that's lack of tail rotor ?
it's the one thing that is a seperate control device. (pedals)

but lift/roll/pitch, that's all the main rotor (cyclic and collective)

[Seahawk]

Originally Posted by svandamme

could some kind of swashplate linkage failure do that? inadvertant roll and loss of control?

Swash plate linkage failure is death. My roommate when I was at the Sikorsky Factory (I was commuting, my family stayed in Maryland) died in this crash at the Factory. He and the other pilot were in a hover doing Compass Rose checks.:

https://aviation-safety.net/wikibase/wiki.php?id=56026

I arrived (I was airborne in a Blackhawk), minutes later. I landed on the front pad at the factory and sprinted back to see if Yong was alive..

The swash plate is everything: Lose that, doneski.

There are some commercial helicopter pilots that post here that will know more.

The 135 has a rigid main rotor system and a fenestron tail so I don't know the impacts of mechanical failure like I do other helicopters.

Let's let the pros weight-in.

[svandamme]

I would think helicopters most of it is very much instadeath when it fails any of the controls ?
loose tail rotor
loose swashplate
Loose the JNut

Can loose power and autorotate, but controls? it's not a forgiving platform for any failures is it?


If I were to win the lottery , I'de be on my way to learn to fly fixed wing the next day
Short of loosing a wing, there is usually room to work the problem and find a way down.
It doesn't scare me .

But Helicopters, man, learning to autorotate, it just seems like there is very little room for error.
And I know it's doable and all that, read lots of books on how they taught young men to learn to fly hueys for Vietnam , so if a 19 year old can do it, surely it's doable, But I kinda don't think i'de want to learn that at 45 , I've eaten most of my brave pills by now

So in this case, i'm not thinking lost the entire swashplate or ful llinkage.
but maybe something got bent or locked up a bit
Just enough but not bad enough to loose full function.

Bird strike in that linkage, could that happen?? ( obviously it would have to be a reasonably big one.. AND have managed not getting chopped up by the blades )

[flatbutt]

Swashplate failure? Oh man how does THAT happen?

[Seahawk]

Originally Posted by svandamme

I would think helicopters most of it is very much instadeath when it fails any of the controls ?
loose tail rotor
loose swashplate
Loose the JNut

Tail rotor failure comes in a few varieties: loss of control, loss of thrust and other more esoteric "issues" like loss of tail rotor authority. They are completely different emergencies. Add to that, the flight regime the helicopter is in because it makes a huge difference in how the pilot will react.

It appears from reading the preliminary report, that this was a tail rotor issue.

Swash plate control. See the video and link below.

Happily, the last JNut helo I flew was the H-57 Jet Ranger.

There are many, many different main rotor and tail rotor designs. The 135 is a great vehicle.

Originally Posted by svandamme

But Helicopters, man, learning to autorotate, it just seems like there is very little room for error.)

When I was in flight school we practiced full auto landing routinely. I have hundreds of them and the TH-57 was a skid helicopter. It really isn't that hard: it is all about energy management: The pilot basically exchanges the energy used to get to an altitude and uses that "stored" energy in the final phases of an auto rotation.

Too much info, I know, but if you win the lottery, go fly a helo. It is, and I have flown just about everything, the best.

https://www.spinningwing.com/the-helicopter/helicopter-swashplate/

[greglepore]

Yeah, he wasn't in auto, the bird was swerving all over the place.
The crew was heroic-the flight nurse held the baby until a lyft driver ran over a grabbed the infant. He then pulled the pilot out from underneath the helicopter. Fuel leaking the whole time.

I don't know whether the pilot had any control authority at the time-he's been interviewed and doesn't remember anything. But if you want to believe in a higher power, go look at the crash site on Google earth-or Dan Gryder's youtube page-it was literally landed against the church, and there were wires in the approach area that were somehow missed.

[svandamme]

Originally Posted by Seahawk

When I was in flight school we practiced full auto landing routinely. I have hundreds of them and the TH-57 was a skid helicopter. It really isn't that hard: it is all about energy management: The pilot basically exchanges the energy used to get to an altitude and uses that "stored" energy in the final phases of an auto rotation.

Too much info, I know, but if you win the lottery, go fly a helo. It is, and I have flown just about everything, the best.

I know it's all doable , like I said, if they can teach it to 19 year olds and send em off to vietnam in such short time.. for the hairy flying they then had to do..
(chickenhawk book , the story about learning on the hiller etc etc, Low level hell)

Lol if I win the lottery, I'll give ya a call I'm partial to a Hughes 500, that thing is cool as a cucumber

[svandamme]

not much footage but that was not a slow decent and it didn't look controlled either..
Looks like they were extremely lucky to survive at all.

[svandamme]

[KNS]

Originally Posted by svandamme

I would think helicopters most of it is very much instadeath when it fails any of the controls ?
loose tail rotor
loose swashplate
Loose the JNut

Tail rotor failure is one of the less desirable modes of failure but as in everything with flying machines there is a procedure to handle the failure.

I had a tail rotor failure in 1993 in a Hughes 300 during climb out. The tail rotor drive shaft became disconnected from the transmission output shaft (the knurled nut was not torqued to spec and safety wire was incorrect gauge). I entered an autorotation, did a tight spiral to a spot beneath me and put it down without balling it up. I spread the skids - the worst of the damage thankfully and my passenger and I were unhurt.

As to the Pennsylvania accident - my office has oversight of the certificate holder and everyone, including Airbus and the NTSB are taking a very close look at everything. It is safe to assume that the details will be a while in coming,

[svandamme]

Nice, glad you did, but I supposed there's no choice in landing spot at that point?
you had it on climb out, so still over airport real estate?

Sounds like something one might not be so lucky if it's a bunch of skyscrapers below you , or steep mountainous /forrested land?
How much control over the spiral is there at that point?

[afterburn 549]

The light I can shed on is from the Nam era - when things go wrong they went wrong fast. like a flash.
It takes one, just one little bolt to break, or to come loose from someone's oversight to wreck the day.
Our losses included not only from small arms fire, rocket (RPG), and other various explosions but from within.
We had one helicopter turn itself about inside out because a push-pull tube came to lose on runup.
Yes, this is connecting the swashplate to the rotor head .
This is a pipe-like-looking object - about 1.5 inch in dia, about four feet long.
A very small bolt retains it at each end . The bolts might have been 1/4 dia (CRS)
It delivers all the input to the rotor head via swashplate (two of these tubes 180 deg apart )
The helicopter became one twisted pretzel in about 5 seconds.

In a fixed-wing, lots of stuff can come to lose and there are ways of getting it to the ground without diaster.
In a chopper, absolutely no failure is allowed to the flight system. *if one input is lost, it is beyond a bad day.
For sure, if it went inverted it was not vertigo in daylight. It was some sort of mechanical failure.

*T/R failure at speed can be dealt with in some helicopters.

[svandamme]

Originally Posted by afterburn 549

In a fixed-wing, lots of stuff can come to lose and there are ways of getting it to the ground without diaster.
In a chopper, absolutely no failure is allowed to the flight system. *if one input is lost, it is beyond a bad day.

That's exactly my understanding as well, you really have to trust the mechanic and whoever made the part cause margin for error is slim to none.

Hence my earlier statement,I'de go flying fixed wing the next day, many fixed wing problems can be worked with or around... Not so with choppers, not sure I wanna risk that once i'm rich and haven't had time to spend my lottery money

[Seahawk]

Originally Posted by afterburn 549

*T/R failure at speed can be dealt with in some helicopters.

Absolutely.

There was a famous, at least in the Navy, of a trail failure incident while two SH-60B's were in form returning to Mayport.

They were at 1000ft agl and 120kts cruise.

The Wing Man noticed that the Leads tail rotor, while turning, appeared to be "windmilling'.

There are two design features on the 60B that helped, the first i that is a wheeled aircraft that can land like an airplane, generally at or above 70kts; the second being that the tail rotor supporting structure is designed to help the 60B fly with a TR failure above 70kts.

We actually practice all the procedures involved both in the simulator and in the aircraft.

The followed all the procedures correctly and did a 75kt landing at Mayport or Jax, I can't remember which. Post touchdown is the tricky parts since the co-pilot has to manually adjust the power control levers to get torque off the tail rotor.

Anyway. They shut down and were towed off the run way. Zero damage.