S-76C++ Down in Latur India

[san2dee]

https://aviation-safety.net/wikibase/wiki.php?id=195651
Maharashtra CM Devendra Fadnavis survives chopper crash in Latur | The Indian Express (http://indianexpress.com/article/india/maharashtra-cm-devendra-fadnavis-chopper-crash-lands-in-latur-4672866/)


Overloading??

[donut king]

https://aviation-safety.net/wikibase/wiki.php?id=195651
Maharashtra CM Devendra Fadnavis survives chopper crash in Latur | The Indian Express (http://indianexpress.com/article/india/maharashtra-cm-devendra-fadnavis-chopper-crash-lands-in-latur-4672866/)


Overloading??

Sure looks like it couldn't climb away......for whatever reason!

[Fareastdriver]

The temperature at Latur is hitting 41 degrees C during the day. It may have been a bit hot for a heavy 76.

[malabo]

Nothing dynamic or purposeful with that takeoff. Looked like it was starting to yaw right as it settled on the wires, so maybe low rpm. Didn't look like much wind from the blowing dust.

My experience with India is that they equated calendar age of a helicopter with airworthiness, so maintenance or spec engines could also be a factor.

Maybe they "manhattan'd" it and stopped drooping just short of blowaway power. Training and SOP - I've seen even large western operators mislead their pilots on the concept.

With 4-6 little fellas as pax it shouldn't have been heavy, not like they loaded 12 rigpigs.

[Max Contingency]

Another clear case of insufficient Bernoullis in the air, pilots are blameless on this occasion.

[megan]

The temperature at Latur is hitting 41 degrees C during the day. It may have been a bit hot for a heavy 76The 76 is a machine for temperate climes. Turn the heat up and it can't pull the skin off a rice pudding. Definitely overloaded, milking and pulling everything available, till he runs into rotor droop and resultant loss of yaw control.

[212man]

Maybe they "manhattan'd" it and stopped drooping just short of blowaway power.

Surely Blow away would have kicked in before LTE took hold?

[Fareastdriver]

The 41 degrees would have been measured in a nice white box. In the open in the middle of habitation with no breeze the actual temperature rockets.

[Frying Pan]

Unreal. You take off....check...you can see stuff ahead....and there are pylons... and boom..

Photo of the aircraft from the front shows the departure field and nothing behind. Surely someone in the crew may have suggested, even a possible downwind take off to avoid flying towards the PYLONS!

Glad nothing more than pride and tax payers money was hurt.

[tartare]

Fixed wing pilot here - can only find limited references to this on web - is blowaway power something peculiar to the S-76++?
I assume it's effectively being able to demand over 100 per cent power from both engines to get you out of a tricky situation?
Does the pilot have to manually select it - or does the FADEC automatically feed it in as collective changes are made - and generates some sort of warning that you are temporarily exceeding power limits?

[212man]

Fixed wing pilot here - can only find limited references to this on web - is blowaway power something peculiar to the S-76++?
I assume it's effectively being able to demand over 100 per cent power from both engines to get you out of a tricky situation?
Does the pilot have to manually select it - or does the FADEC automatically feed it in as collective changes are made - and generates some sort of warning that you are temporarily exceeding power limits?
It's common in modern twins. The FADEC normally limits engine power to respect the gearbox limitations but, once Nr decays to a given value, they will adjust the fuel scheduling to allow maximum single engine power from each engine. Typically this will result in maintenance action and possible gearbox change, but may save the airframe! It's automatic with no pilot input.

[tartare]

Many thanks.

[Vertical Freedom]

Incredibubble - before any launch on would assume the PIC asks a few basic questions of thy self including but not limited to these couple; how much power margin do I need to escape from here & after pick-up, what margin do I actually have....is this departure doable???? :* just saying like :ugh:

[Sir Korsky]

If you keep pulling on the collective increasing blade pitch, the rotor will droop when aerodynamic demand has exceeded power available from the engines. To limit rotor droop and subsequent rotor effectiveness, both engines will auto arm to 2 minute power automatically with the rotor RPM decay. The increase in temporary blowaway power from the engines, may save you from your impending situation. 2 minute power in the 76 does not exceed the maximum design limit transmission torque. Utilizing 2 minute power will accumulate towards engine maintenance schedules. I believe 10 minutes of 2 minute power can be accrued before an engine tear down is required. All S76 models have blowaway power available. 2 minute power does not end at 2 minutes. You can pull for as long as the engine will hold up as you're operating outside of the certificated design limitations.

[Vertical Freedom]

Sir Korsky, or the Pilot could've aborted the departure to off-load a few bags of Spuds :D

[malabo]

Just looking at the pull to high hover and no droop in rotor, I know a hundred pilots that could have walzed that aircraft outta there. But it would take skill and some finesse, and understanding of the FADEC. A couple seconds at blowaway are nothing when you can accumulate 10 minutes in the life of the engine, though unlikely you'd even get to blowaway if you used that droop to accelerate instead of trying for an HOGE that isn't going to happen.

In our PC1 world we forget what aircraft can do PC3. The takeoff limitations in the RFM are based on 150fpm OEI, that's all. We'd wrestle overloaded 76A models in Africa, Iran, SE Asia, Australia where all we would get was a couple feet hover and could only dream of how high this guy was holding it up. The C++ is pretty good at high temps, and the FADEC is biased to account for it. Anyway, you can always substitute skill and finesse with regulation and make everyone buy 139's and operate them at less than 6000kg.

[HeliTester]

All S76 models have blowaway power available.I believe that should read "S-76C+ and newer models have blowaway power."

[212man]

All S76 models have blowaway power available Apart from A, A+ and A++ (and by assumption, The standard C).

2 minute power in the 76 does not exceed the maximum design limit transmission torque. Utilizing 2 minute power will accumulate towards engine maintenance schedules. I believe 10 minutes of 2 minute power can be accrued before an engine tear down is required.

That's for OEI - if you have both engines sticking 127% Tq into the MGB I'm pretty sure that will require MGB maintenance action!

[Sir Korsky]

Thanks for making me get the books out 212, I needed a brush up. I was told all models have Blowaway, luckily never flown an A so the jury's out on that one. You get 10 seconds transient at 230 trans torque. DECU limits blowaway power to 115 tq per side.

[212man]

Thanks for making me get the books out 212, I needed a brush up. I was told all models have Blowaway, luckily never flown an A so the jury's out on that one. You get 10 seconds transient at 230 trans torque. DECU limits blowaway power to 115 tq per side.

No juries required! Blowaway requires a FADEC so discount an Allison, an Ariel 1 variant and probably the B model too.

[tistisnot]

If memory serves me correct the S76B MGB was limited by EEC's in blowaway to 136% Tq each engine as opposed to the dual engine limit of 100% Tq per engine with a 10 second transient of 115 / 230% Total Tq ?

[HeliTester]

tisitisnot....I stand corrected. Located an S-76B RFM describing the blowaway function on that model. States that the dual engine limits are reset to 844 T5, 101.6% N1, and 115% Q When Nr droops below 98%.


212man...Sorry I misled you in my PM.


HT

[Sir Korsky]

The B model Blowaway info is located in the RFM PT6 engine supplement if anybody cares.