Flight data/cockpit voice on Kobe crash
 

RIP to all the crash victims.

Was this helo operating under Part 135? What are the flight data recorder and CVR requirements?

My understanding is in a previous life it was commercial. So maybe yes.

A CFIT accident it seems scud running VFR, I hate to speculate but by that last photo seems that way. RIP to everyone aboard.

You sure? The last bit of data from the flight showed a vertical speed of -4,800+ with 161 kts


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I wouldn't consider instantaneous mode C data to be accurate, absent other info. It's not a designed to be an FDR.

My helo knowledge is very limited, but I do know that a ‘retreating blade stall’ can occur after an abrupt pull up, especially when operating at high gross weight and high speed. The result of such, is loss of lift and a rolling motion to the left.

Could the pilot have suddenly realized his terrain situation, and initiated an abrupt pull up, and inadvertently stalled? This could account for the left turn and sudden altitude loss.

Another thought. Has this model of helicopter ever had an instance of the rotor disc contacting the tail boom, after an abrupt pull up?

this is what I believe to have happened

Guess we can send the NTSB home. Jeff has it all sorted out. Gotta be a record - not sure the fire from the crash is cold yet. :rolleyes:

Nevermind. Had footage but don’t think it was the kobe crash

While the terrain does resemble SOCAL, that crash video does not match eyewitness reports or the weather conditions known to exist at the time of the crash.

Also different paint job.

Blue and white, right? If you saw the other gray-black picture, I think that was promotional plastic wrap.

The wreckage is blue and white. There are two pictures of the airframe floating around, one is a "carbon" style paint job, the other is the obviously more recent blue and white.

Yes we can decipher every detail, though the cause is nothing new.

The work ‘Uncle’ comes to mind.

So what happens now? The aircraft didn’t have a black box? Does this mean this will be a mystery?


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Oh. Nvm then!


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If it's derived from ADS-B Out, it's usually highly accurate w/1 second update.

1. Retreating Blade Stall: Not likely the culprit here. If anything the abrupt cyclic input would result in a transient droop in rotor RPM, which could be exacerbated in high/hot/heavy conditions (not the case here). Rotor blade stall is typically something you'd expect to encounter in a high speed, power-on dive, not while performing an aggressive climb to clear a cloud layer. Thinking about this phenomena as you would a typical fixed wing airplane stalling isn't going to do you any good. Simply increasing AOA in helicopter (read: nose attitude in relation to the horizon), no matter how abruptly, is not going to result in a stalled condition. If the climb is continued and conditions are right (i.e. high/hot/heavy situation) power required will eventually exceed power available and the aircraft will begin to settle.

2. Rotor disc contacting the tail boom: The fully articulated rotor head found on the S-76 is more efficient and survivable than something you might find on aircraft with an underslung rotor system (see AH-1W, UH-1N, Bell 206, etc). In negative G situations, the possibility exists for underslung systems to "flap" resulting in something called mast-bumping or even the main rotor blades impacting the airframe. With the fully-articulated head, this is not something that would really ever be a concern. If you wanted to, you could unload the head significantly with little to no impact on aircraft performance.

Many things could have happened here, but looking at the weather, the flight path, and hearing the ATC communications in the minutes before the crash, it's easy to look towards spatial disorientation as a likely culprit. Reference the crash of the Army H-60 carrying the MARSOC team off Panama City a couple years back, and you'll see similar things (even with 2 pilots). A strong cyclic pop into the clouds resulting in what would have to be an immediate transition to an aggressive IFR scan is a recipe for disaster, especially in a single piloted aircraft. Having felt the effects of severe spatial-d many times in many types of helicopters, I can attest to the fact that it is not something easily recognizable. Couple that with close proximity to mountainous terrain and the results can, and have been, disastrous.

Loss of control
 

This is just a horrible tragedy, and aside from a catastrophic mechanical failure, I was trying to find a sequence of events that an experienced pilot could allow to happen that would have resulted in this accident. Completely conjecture of course, but after reading the insight from RotorTrash and viewing this recreation of the flight path in VFR conditions (skip to the last 2 minutes),

Accident path flown VFR

I'm left wondering if the answer isn't just as simple as that.

I know fixed wing commercial aviation life, and that you are trained to get out of inadvertent IMC; but how hard is it for an experienced single pilot helo to do a 180' turn in IMC? If this guy flew in the LA basin he must of had plenty of actual time, how could this do him in?

I know fixed wing commercial aviation life, and that you are trained to get out of inadvertent IMC; but how hard is it for an experienced single pilot helo to do a 180' turn in IMC? If this guy flew in the LA basin he must of had plenty of actual time, how could this do him in?[/QUOTE]

I'm by no means insinuating that any of this or what I wrote previously happened here, just to get that out there, but the transition from IMC to VMC low to the ground can get you pretty quick in a helicopter. Even an experienced IFR pilot can find himself/herself in a situation where they think they're wings level when, in fact, they're 60 degrees left wing down. Most here are well-versed in the various illusions that you can experience without adequate visual cueing, but from my experience it is even more pronounced in a helicopter (I'm now a 121 guy except for one weekend each month, if that counts for anything). A climbing, decelerating turn in the goo can do some pretty gnarly things to your sensory abilities. I've seen guys (me included) keep on rolling through a turn all the way towards 90 degrees still thinking that they've rolled out on course, as well as those (myself) flying along "straight and level" before the rotor RPM horn is screaming at them as they begin to effectively slide backwards out of the sky. It's amazing what the inner can convince the body of. That video was interesting, but the lack of ceilings and fog present makes it seem like much more of a benign situation than it most-likely was in real life. As you get forced lower and lower, things can start to degrade on all levels to include your instrument scan.

This is without a doubt a horrible and tragic event. Hopefully they can gather some information that sheds some light on the cause. At this point, anything is possible, but those conditions (based on my location in SoCal and weather reports to this point) were not something that I'd be comfortable flying in, especially in a single piloted aircraft with passengers on board.

It appears he clipped the very top of the ridge and was 20’-30’ away from salvaging it.
Tail and main portion of the wreckage are on different sides of the crest.

F/W dude here, who's admittedly out of his element in analyzing this accident. Though I'd really be interested in hearing from someone who regularly operates helos in the LA basin to understand if IFR ops there are even a practical option. I could believe that ATC congestion might wipe out the whole time/convenience argument of flying a helo in the first place. But at the same time, if there was ever a day when going to the trouble of filing and then just flying in the clouds (vs. trying to avoid them) would have been the safer route, it was a day like last Sunday. :eek:

We do it all the time but typically it’s easier to just follow the freeways VFR like the mishap aircraft did. ATC is great and treats us like any other IFR-filed folks when we do file. So yes, very practical, just not usually necessary (maybe it’s this attitude that leads to events such as this). Special VFR isn’t a problem, but once you get into the hills it’s easy to get stuck should conditions catch you. I’d imagine it’s largely dictated by company SOPs and protocols, not to mention any perceived sense of urgency to get the guy where he needed to be. Again, this is from a military point of view with zero corporate helicopter experience.

That unfortunately echos a vast number of CFIT accidents. So many of them just so "barely" didn't make it to clear the top of the mountain/ridge.

So true... I’d welcome a corporate helo perspective here.

Highly, highly unlikely. True, he hit just below a crest of a small ridge, but that ridge was surrounded by other much higher ridges. Factor in that he was descending at 2000fpm (disoriented and out of control), the fact that he hit 20-30’ below a ridge was pure, well, I don’t want to say coincident but he had to hit somewhere. As a former Navy helo pilot and prior S-76 pilot in the Gulf of Mexico where we flew IFR routinely during the winter, I don’t understand how he lost control so easily. He did the wrong thing by scud running in those hills, but then he did the right thing by getting on the gauges and trying to climb above the terrain. If he was rated/current/proficient on instruments, he should have been able to pull that off.

As Tandem46 mentioned, and described in the NTSB brief there were other, some higher, peaks in that area too.

https://m.youtube.com/watch?feature=...&v=Vwk6NaQSuPA

Not familiar with the locals terrain.
Did hear a blurb on the news that the operator only had a VFR 135 certificate.
In which case the pressure to continue may even have been higher.

There was a kids basketball game to get to that started in 1 hour. Sadly, that was the pressure.

Don't know what a guy with that kind of money was doing using a single-pilot VFR operator in a cloud-prone area. The pilot's certs and ratings seem pretty basic, not sure if you'd expect a professional helo pilot to have perhaps some heavier type ratings?

There are very few civil helos that require type ratings. The S92 and Boeing 234 (Chinook) come to mind, and maybe the bigger AW and Eurocopters. There would be very few opportunities for type ratings in these aircraft.

Zobayan had Comm helo, instrument helo, and helo CFII. The only apple missing is ATP. IMHO, his times would be considered quite acceptable for his job. I am sorry I cannot recall where I read the breakdown on his total time (8200), helo time, and time in type.

Are autopilots common in helos? Or even more specifically in the S76? As a guy who has never even ridden in a helo, I genuinely don’t know. Just wondering if that capability is there to help out in single pilot situations like this?

Also I agree with someone else that the pressure of getting to the basketball game will likely be a major factor. That even may have been what drove the decision to not file IFR.

He couldn't file instruments because the company operating cert. was VFR only.

I don't know if the S76B is approved for single-pilot IFR. Help, anybody?

Reading a rotor forum, they say that the S76B can be flown single pilot IFR with the proper FUNCTIONING autopilot and company certification. They say most rotor guys in the LA area fly I Follow Roads.

This answers SO many questions. I'm hopeful it will result in some changes. The corporate helicopter world sounds a lot like pre-regulation day airplane barnstorming days.

I think it will... they couldn't have come up with a better way to get the eye of mordor glaring at them if they had tried to.

Here's how it goes down in most CFIT accidents:

AIrcraft is running in the obscuration and can't see more than a few hundred feet ahead, if that. Maybe even trying to let down. They think they are in a safe corridor or area, but when the vis is low it plays all sorts of tricks and you don't realize you are not quite where you think you are. Suddenly, a mountain/hill approaches right in front. They pull back for all they are worth, gaining altitude, but it's not quite enough and they crash just below the top of the mountain/ridge/hill. More than a few have skipped off the front side (just below the top) to tumble down the backside. It happens too fast due to their forward speed. It's usually not a climbing maneuver because they "entered IMC". It's a last-ditch climbing maneuver because cumulus-granite appeared right in front.

^^^^ except for the part about the 2000 fpm descent right before impact.

FYI, for those asking, AOPA is reporting that the pilot had 1250 time in type...

When flying a helo in IMC, what is the minimum forward speed you can maintain?

I was speaking generically, but yes. I was considering adding this and talking about the specific accident more. Definitely can't rule out mechanical.