Blackhawk Crash Alabama
 

Just heard a Blackhawk has crashed in Huntsville Alabama, anyone have more information?

just found this

No survivors in fatal Madison County Black Hawk helicopter crash, officials say

• Updated: Feb. 15, 2023, 5:22 p.m.|
• Published: Feb. 15, 2023, 3:48 p.m.

https://www.al.com/pf/resources/imag...ook.svg?d=1003
https://www.al.com/pf/resources/imag...ter.svg?d=1003

NEW!

By

• Howard Koplowitz | [email protected]

Authorities responded to a helicopter crash Wednesday afternoon in Madison County that killed all people on board, officials said.

Authorities were dispatched to Burwell Road and Highway 53 at 3:01 Wednesday on a report of a crashed helicopter, said Don Webster with Huntsville Emergency Medical Services, Inc.

The helicopter was burnt.

Tennessee National Guard as reported by NBC news

Video below purportedly showing crash.
Appears to be an extremely high rate of descent - what could have caused that?!

practice SWP with harsh aft cyclic input

I hope the Flight Data Recorder survived, if there was a component failure leading up to this incident it would be good to know.

Lima models have had main rotor blades shed skin a handful of times and the aircraft landed safely. Maybe not this time. Tragic.

60mech

Now that Sir Korsky has solved the cause of this tragedy we can move on to other matters.

Care to explain how divined that information so quickly and with such certainty?

To me his post comes off less as asserting a cause rather than just a response to the question “what could cause such a high rate of descent”

That video is also shown as part of this article:

https://www.dailymail.co.uk/news/art...survivors.html

In this case it is an overall (rather than cropped) view from what looks to be a home security system running. But doesn't the audio in both cases sound very unrealistic, as if dubbed in afterwards? The video looks credible in which case the helicopter was in serious trouble from a substantial height.

It appears from that video that the aircraft came out of cloud inverted.

Edit:

Or, at least going inverted shortly after.

I flew Blackhawks for a few years and I can think of one failure that would cause the aircraft to pitch nose down. If the (normally automatic and active) tail stabilator motors fully down in the cruise (it should be up by around 40kts IAS if my memory is correct but it was almost twenty five years ago) it needs to be promptly dealt with by selecting it to manual and motoring it up to a neutral position.

If instead the stab is left down and the cyclic is moved an long way aft, in an attempt to correct the nose down attitude, it may be possible for the MRBs to contact the rear of the airframe.

What happened to the aircraft below had happened at least 3 times previously, but after thinking about it I don’t know that a worse failure(losing more surface area of the blade) would be the cause of this most recent incident. It seems like this would most likely result in the aircraft breaking up in flight.

I think responding to a stabilator failing out of auto mode improperly as others have suggested could have caused something like this. New York national guard had a crash caused during a checkride where the instructor pilot manually slewed the stabilator down in cruise flight while simultaneously silencing the master caution(at night under NVGs as well) The pilot on the controls didn’t have time to react to the failure.

There was also an accident in Maryland a few years ago where the entire tail rotor gearbox separated from the aircraft due to vibration from a failed tail rotor blade. The emergency procedure that came out of that one is optimistic to say the least.

https://cimg5.ibsrv.net/gimg/pprune....13d270d05.jpeg

Most accidents seem to come down to human factors, lessons can be learned and applied and I still feel
confident in the aircraft as a platform. Honestly, this one is getting to me because at this (very early) point it just looks like the aircraft killed them.

60mech

One thing to remember when viewing the video of the aircraft is the distance from the camera to the aircraft and the delay that causes between what you see and what you are hearing.

Consider the time lapse between when the aircraft disappears behind the tree and the time you hear the sound of the impact to get an idea of how much lag there is caused by that distance.

As to the NY Crash.....the IP did a very stupid thing and earns the responsibility for that crash and the aircraft should be seen as a victim.

Early on in this investigation there shall be some indication of whether the Rotor Head departed the aircraft or not and depending upon the location of the parts discovered will tend to point to where in the sequence of events that occurred if at all.

The Black Hawk is a proven aircraft and has been tested thoroughly from initial prototype stage right along to today.

As to the aircraft was thought to appear from out of the clouds then ATC should have recordings of any Radio Transmissions to/from the Aircraft as they would have in all likelihood been on an IFR Flight Plan or operating on an IFR Clearance of some kind.

The prevailing weather did not seem to be of the kind that would offer a risk of IIMC.

SASless,

I looked back at weather conditions at the time of the accident, overcast 1300 feet. We were talking in the office about possible spatial disorientation leading to a loss of control, but seems a stretch. It just seems like something had to have broken to get to this condition.

it’s a very populated area so if parts were coming off maybe something will be recovered.

I also have questions re how the video squares with a Stabilator failure, assuming it went full down in cruise flight for example, and how the aircraft would react.

My thought is the video shows a nose down pitch attitude but with the high rate of descent in that nose down attitude it seems to me the nose would have tucked more with the increasing airspeed and gone inverted.

Not saying that is my choice of causes....just trying to look at the video and question what we are seeing as we try to come up with possible causes.

What model UH-60 was it?

What kind of SAS/AP/FD gear did it have if any?

What was the nature of the training being conducted?

Were these Full Time Guard Pilots or Part Timers?

The formal investigation will offer up a great deal of information when it is all said and done.

SASless,

Great questions, here’s the current EP from the checklist:
https://cimg6.ibsrv.net/gimg/pprune....a3ab74d9d.jpeg
Now, I haven’t personally experienced a stab failure where the stab slewed down in cruise flight, it’s either failed to slew(program) up on takeoff(stayed -40degrees) resulting in the nose dropping, or one time it slewed full up (+10degrees)and stayed full up on takeoff resulting in a nose high attitude.

Pilots I work with who have experienced a stab programming down at higher speed combined with reduced collective have indicated it is a sobering experience and the speed at which the nose tucks is quite rapid.

Another accident in Egypt was caused by a stab that was repeatedly failing out of auto mode but they kept flying, manually controlling the stab. Then they did an airspeed over altitude takeoff from a cliff side LZ, where people liked to “dive” over the side of the cliff, the stab was still failed full down, resulting in a crash into said cliff face.

I certainly hope that nobody was messing with manual control STAB switch, there have been too many accidents due to that sort of thing.

In the video of the daily mail it appears to change instantly from not seeing it at all to seeing it very clearly. So it clearly appears that it flew in rather dense clouds and thus IMC when LoC occured. If that was IIMC and if this happened due to spacial disorientation or if the cause for the LoC was a mechanical malfunction obviously only the detailed investigation will be able to tell.

Experienced UH-60A Stabilaor Failure in cruise flight Circa 1985
 

On a return flight from Hartford, Ct to the Sikorsky Plant we experienced a stabilator shut down. It was determined that a mis-compare of the dual actuators caused the shut down. At failure the aircraft pitched nose down following the trailing trailing edge down movement of approximately 3 to 4 degrees. We manually set the stabilator to 3 degrees trailing edge down and continued to the Sikorsky Plant where a relatively normal landing was made. The only anomaly being a little greater nose up attitude during approach and landing..

Wasn't there an accident in the late 1970's that put one aircraft in the water in a similar manner to this latest accident?

It might have been at PAX River....but had two Sikorsky Pilots onboard?

Found it....not at PAX River....but near the Factory.

https://aviation-safety.net/wikibase/77705

it’s like 737Max decades earlier.

Another bit of information came to today....re the Rotor sounds on the audio.

The Main Rotor emits a N/Rev 4P 17.6hz sound but the tail rotor emits a slightly higher pulse of 21hz causing a problem telling the difference between them by ear. I am assuming that is during "normal operation" with standard Nr set by the Crew.

As poor as the one video is it can still provide a lot of information when examined by the investigators.

Thats the same UH-60 airframe colloquially known as the lumberhawk from the Kentucky incident a few years earlier.

https://cimg7.ibsrv.net/gimg/pprune....72ae0c0071.jpg

looks like a good outcome?

It happened before my time at SA, We were briefed that the aircraft was in a high hover over the Housatonic River. The Stabilizer failed in the full trailing edge down position when the pilots pitched over to accelerate into forward flight. The pilots were not able regain manual control in time to prevent contact with the water. The functionality of Stab manual control switch was brough into question and ultimately secondary control switches were installed in front of each pilots cyclic grips.

The tail rotor blade failure sometimes colloquially called “blade collapse” could be another crash initiating event. The metallic pitch horn / snubber housing can disbond from the tail blade skins and cause progressive failure as the blade trailing edge unzips, allowing the horn to migrate further outboard, which unzips the skins further and eventually the blade is largely destroyed. Sometimes the horn migrating outboard keeps the tail rotor 1P somewhat in a tolerable zone and the consequence is a loss of tail rotor authority. Sometimes the tail rotor 1P is more severe and the TR gearbox and rotor assy leaves the aircraft.

Hopefully the investigators determine the actual cause instead of us keyboard engineers yammering at each other.

Crew details

https://www.tn.gov/content/dam/tn/mi...20Crash%20.pdf

I was going to be mean and rag on an “expert” the local media interviewed on this incident, but then I thought about it and he was doing basically the same thing as we are here, except his speculation wasn’t as informed as ours.
The main comment that I took issue with was this one:

“Helicopters probably don’t have a flight data recorder or a cockpit voice recorder, so what they’ll do is just basically try to… investigate the accident and try to see what, if any, failures of any components,” Williams said. “I would basically look at the main rotor first and of course the tail rotor.”

I guess flight data/CVR isn’t common in the civil rotorcraft world? The H-60 surely does have both, hopefully the IVHMU where they are contained survived.

In the same article it was stated the aircraft was enroute to Madison County Executive airport, I had assumed they had departed from Redstone Arsenal or Huntsville International, I guess because I perceived some forward motion of the aircraft when there wasn’t any.

Depends on the MTOW and is regulated by the authorities.

skadi

Definitely not common in the US and it has been a complaint by the NTSB for years. After they participated in the Finnish Copterline 103 S76 (which did have a CVFDR fitted) accident investigation they formally wrote to the head of the FAA. https://www.ntsb.gov/safety/safety-r.../A06_17_18.pdf
Europe has mandated them for offshore and Part 29 aircraft for many years, and they have been invaluable.

FYI: that changed about 10 -15 years ago. Most GOM twins have CVR/FDRs installed even thought the rules didn't require. Part 135 was updated about 10 years ago to require recorders in certain twins. You even found them in EC135s when they flew the GOM. There is also a move to install in single turbines with some operators doing that now. The problem years ago was there wasn't a recorder that would "fit" in small single turbine helicopters. Now there are several smaller recorder options with STCs which have made their way into some EMS singles.

Well that's good to hear then - a mixture of the NTSB and the Oil companies I guess

Remember this accident involves a US Army Black Hawk helicopter and the Aircraft Spec is derived from US Army Specifications not the FAA or NTSB.

Also, the NTSB can suggest only and it is up to the FAA to require such devices.

The NTSB has made many such "suggestion" that the FAA has refused/failed to implement.

Also as Wrench rightly points out there are legitimate issues that have been a hinderance.

It is not just the Operators that are the problem.

Re the 8/9/76 11:15PM event at Ft Campbell. Received a call at home 30 min later, and before noon on the 10th a small Sikorsky team led by Bob Zincone (who had taken over development of the UH-60 in January 1975, after three months of flight test) was on the ground at Ft Campbell.
Note: Have three pics that amplify the situation but even though saved as Jpegs-cannot get them to open for transmittal here.
One main blade displayed a peeled back outer surface, initiated at the point where the blade meets the tip cap. That peeling extended maybe 15 ft inboard and some of the Nomex honeycomb was lost with it. Blade aerodynamics changed dramatically.
Crew was flying a simulated infantry lift, with a squad in the cabin with weapons etc.
Flying a a few hundred feet and 145 KIAS or so, the peeling caused immediate and high one per rev vibrations that even made the primary servo caution capsule blink a few times. ( remember, this was prior to availability of NVG’s ). Decision to land immediately was made and they did that, coming down so vertically that the tail rotor took divots out of the same side of a pine tree as they descended. ( Hopefully the picture I have of one of the other three blades having come to a stop against one of the pine trees with a couple of them that had been hit and broken off by the main blades during landing will be available for later viewing-its a saved jpeg and therefore should work here, but doesn’t ).
There was one injury: upon landing the squad leader told the squad to follow him as he was jumping out of the right cabin. BUT, it was dark, and the ship had come down straight alongside one of the pines so the Sgt went about 12 inches and bloodied his nose on the pine tree.

The SA group had brought some gear and did borescoping of the drive train boxes and engines and found no evidence of sudden stoppage. The UTTAS program included a requirement for blade etc replacement capability in the field, so the contingent of Army maintenance folks ( trained by SA-the same sort of group existed on the Boeing side ) unlimbered the portable maintenance crane and started removing/replacing the rotors. Another team of troops from the 101st* arrived with chain saws etc and started clearing the area where the UH-60 main rotor had started a clearing-unintended.
* Ft Campbell is home to the 101st Airborne Division

That work continued into the next day-followed by doing ground runs for main/tail track and balance ( all done by the Army crews ), and on the next morning ( the 11th ) the Army crew flew it back to the cornfield which was the base of operations for the field evaluation. Army flight regulations required a check ride by a standardization pilot for the two aviators involved , so, the Army not yet having same, it was agreed that I play that roie and in order not to mess up their flight schedule, those two checkrides started at midnight ( as I mentioned-this was the 101st ). Those blades and that drivetrain remained with that aircraft.

We found that our manufacturing procedure was at fault. There are three wraps of fiberglass at differing angles which form the outer blade skin. Out at the end of the blade, we had done a straight cut though the skin. The peeling started there. Corrective action was to change the design by folding the skin over and underneath, closing off the edge.

Ft Campbell Blade 8/10/76
 

https://cimg5.ibsrv.net/gimg/pprune....c6ca3badd3.jpg
Sorry for the orientation. Pine trees were 3-4 inches, thus the rotor did not experience a sudden stoppage.

Pine trees are pretty soft and flexible at that size......Bamboo although flexible is much tougher material.

Good thing it was not mature Oak Trees.

To be fair, the FAA has to follow processes - including a cost/benefit analysis and public comments (can be bypassed only if it's judged to be an air safety emergency). Plus, the FAA moves at the speeds of bureaucracy (i.e., slow, slower, and slowest).
The NTSB has no such obligation - they can recommend anything they see as having potential value.

True, of course, however, comma..,,

Saw this picture earlier:


https://cimg3.ibsrv.net/gimg/pprune....57d1dfbe5.jpeg

Appears to show Tail Rotor Gearbox next to the tail
pylon, so the one theory that some of us had (including myself) of the gearbox departing the aircraft seems to not hold up at this point.

The IVHMU is mounted in the avionics equipment rack in the tailcone, approximately 3 feet aft of the main fuel cells. If the tail pylon is in this condition perhaps the tailcone/aft transition section is in a similar state.

The post crash fire would be the big hurdle the CVR/FDR needed to survive.

Also confirms that was a UH-60L.

Any sign of the Main Rotor Blades?

Sasless,

I think there might be a piece of one in the larger picture, I had cropped it down for clarity. I couldn’t tell if it was Main or tail rotor fragment honestly.

Screenshot from latest edition of Flight Fax:
https://cimg7.ibsrv.net/gimg/pprune....041be9010.jpeg


I hope this doesn’t mean the end of the investigation, but it appears they don’t have any idea what happened at this point, and may never know.

FltMech