Navy helicopter crash Inyo CA 7/17/21

[PeterNSteinmetz]

MH-60 Knighthawk. Looking for a lost hiker. No fatalities.

https://www.foxnews.com/us/navy-helicopter-crashes-crew-california-mountain

 

[Arob16]

Glad everyone made it out alive. We used to see Blackhawks rescuing folks a lot when we used to live out there, hiking Mt Whitney every season. Those hills are not for the amateur hiker.

 

[Velocity173]

Well, no telling how they went down but if they got below ETL at 11,700 ft, summertime temps and in a heavy MH-60S…bad things happen.

 

[PeterNSteinmetz]

Well, no telling how they went down but if they got below ETL at 11,700 ft, summertime temps and in a heavy MH-60S…bad things happen.

12,000 foot service ceiling? What is ETL on one of those at sea level?

 

[Velocity173]

12,000 foot service ceiling? What is ETL on one of those at sea level?

I’m showing a 13,000 ft ceiling on the MH-60S. No idea if that’s what their NATOPS manual shows or not.

The book service ceiling pretty goes out the window for a helicopter conducting SAR. For instance, a Black Hawk service ceiling is 20,000 ft. but no way you’re hovering there to hoist someone up. That’s why you have a hover OGE and hover IGE ceiling. That’ll be much lower than the book service ceiling because in the book service ceiling is using forward flight. Above Effective Translational Lift (around 20 kts) the helicopter uses far less power (to a certain point), therefore you can sustain flight at a much higher altitude.

Similar to this vid, the engines on this HH-60 reached their limit. Slightly different in that it was an engine speed limit vs the Navy MH-60 would be a temp limit…if indeed that was the cause. Once you reach that limit, the rotor droops, the aircraft settles and if you haven’t given yourself a “bailout” direction, you’re screwed.

 

[Velocity173]

Just a rough calculation for those conditions. With 12,000 PA, 10 C, max weight they could hover at OGE would be around 16,500 lbs. Thats using perfect spec 1.0 engines. Aircraft are almost never at spec though.

 

[Velocity173]

Well, still no telling how they crashed but when you gotta launch a CH-47 to pick them up because another MH-60 can’t, that kinda narrows it down.

https://www.navy.mil/Press-Office/P...er-crew-rescued-after-crash-near-mt-hogue-ca/

 

[donjohnston]

I’m showing a 13,000 ft ceiling on the MH-60S. No idea if that’s what their NATOPS manual shows or not.

The book service ceiling pretty goes out the window for a helicopter conducting SAR. For instance, a Black Hawk service ceiling is 20,000 ft. but no way you’re hovering there to hoist someone up. That’s why you have a hover OGE and hover IGE ceiling. That’ll be much lower than the book service ceiling because in the book service ceiling is using forward flight. Above Effective Translational Lift (around 20 kts) the helicopter uses far less power (to a certain point), therefore you can sustain flight at a much higher altitude.

Similar to this vid, the engines on this HH-60 reached their limit. Slightly different in that it was an engine speed limit vs the Navy MH-60 would be a temp limit…if indeed that was the cause. Once you reach that limit, the rotor droops, the aircraft settles and if you haven’t given yourself a “bailout” direction, you’re screwed.

Could they have spun around 180 degrees and flown out of that situation? (I know nothing of helo's or mountain ops)

 

[Velocity173]

Could they have spun around 180 degrees and flown out of that situation? (I know nothing of helo's or mountain ops)

The Mt Hood crash vid? Hard to say. They got hit with a gust of wind. It looked like they tried to fly out of it but they just didn’t have enough altitude and had a tail / X wind. But yeah, if you’ve got the collective up in your arm pit, the low rotor (steady tone) alarm is going off in your helmet, kick right pedal, nose it over and fly out of it. Speed is your friend.

From what I’ve read they didn’t do a second power check at altitude. That is done by pulling up to a hover near the LZ but with plenty of altitude to abort or bail out to the side (preferably right side). Basically checking to see if you have hover OGE capability.

 

[Tarheelpilot]

The Mt Hood crash vid? Hard to say. They got hit with a gust of wind. It looked like they tried to fly out of it but they just didn’t have enough altitude and had a tail / X wind. But yeah, if you’ve got the collective up in your arm pit, the low rotor (steady tone) alarm is going off in your helmet, kick right pedal, nose it over and fly out of it. Speed is your friend.

From what I’ve read they didn’t do a second power check at altitude. That is done by pulling up to a hover near the LZ but with plenty of altitude to abort or bail out to the side (preferably right side). Basically checking to see if you have hover OGE capability.

The version of the story I heard was the crew used the HW in their performance assessment and when it sheared to a tailwind it stopped flying. Curious if that’s actually the case.

 

[Warlock]

You can be through ETL with a headwind at a hover or even a strong tail wind with good flight stabilization…the latter situation can get bad if you move forward and drop out of ETL at high DA or Heavy…the result is a cascade of events that can induce settling with power…

 

[Velocity173]

An even heavier 60 trying to hover in marginal power conditions. Too hot, too high and too heavy. No, it’s not possible.