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Dili Black Hawk

Old 5th Aug 2007, 04:39
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Dili Black Hawk

From "The Australian" newspaper

Defence kept mum on Dili crash

Mark Dodd and James Madden August 03, 2007

AN investigation has been launched into the crash of a Black Hawk helicopter on the outskirts of Dili more than five weeks ago.

The Australian Defence Force did not announce at the time that a crash had occurred and confirmed the incident only after calls from The Australian.

There are concerns the crash might be linked to "rotor droop" - a sudden loss of power cited as a possible factor in another Black Hawk crash, off Fiji last November, in which the pilot and an SAS trooper were killed.

No one was hurt in the Dili crash but the chopper suffered extensive damage. In response to questions, Defence yesterday confirmed the incident, which occurred during "routine night operations assault training".

The US-designed Black Hawk, the workhorse of the army's troop-lift transport operations, made a hard landing at Dili's Comoro heliport, the site of a large Australian military base.

"The aircraft suffered damage to the underside of the fuselage and was freighted back to Australia on an RAAF Hercules," a Defence spokesman said.
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Old 5th Aug 2007, 05:30
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I don't think this incident was "hushed up" so to speak. I recall reading about it in the media several weeks ago.

As for the term "rotor droop" as mentioned here (and in other media reports), being described as a "loss of power". This might unfairly present a connotation to the layman that there was some sort of technical problem with the engines resulting in them losing power.

It might well be the case, of course, that the engines were "topped out" and producing the absolute maximum amount of power (or more) that they are designed to produce (i.e. no technical problem), yet the rotor speed could not be maintained simply because the power demanded (by the pilot) was in excess of design limits.

So, has it been explained at this stage one way or the other whether there was any real loss of power, or that the engines were OK? I think media reporting here and the explanations provided could be better.
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Old 5th Aug 2007, 07:37
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Relatively uninformed guess as appropriate to a rumour forum - I think it may be the rate of power demand rather than the amount called for that could possibly be leading to Nr droop.
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Old 5th Aug 2007, 09:18
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Odds are it was pilot error like the ship landing that went bad.
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Old 6th Aug 2007, 00:25
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The S70A-9 has always had an issue with Np/Nr droop, due to the analog ECUs on the engines. This was identified as a problem back in 1989, and the proposed fix from GE was to retrofit the fleet with digital ECUs. The decision was made by Army not to fit the digital ECU at this time. The analog ECU just cant cope with a rapid and significant power demand.

The later S70's, eg China Hawk and Turkish Hawk were (I think) fitted with digital ECUs...
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Old 6th Aug 2007, 00:33
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"problem" is in the eye of the beholder. the response rate of the analog T700 is eye-watering, especially compared to older helicopters. The fuel control easily responds to full power from zero power in 2 seconds without drooping below about 95%. If it is a "problem" there might be some reason why a tactical utility helicopter is placed into situations where it needs to withstand 1 second full power pulls. These engine acceleration rates are dictated by the engine design, not the fuel control, since the stall protection of the engine dictates the max power rate.
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Old 6th Aug 2007, 02:27
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Agreed....
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Old 6th Aug 2007, 02:44
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Everything has a limit!!!!

If the power required exceeds the power available, RRPM will always decay, this is basic stuff. What also needs to examined is the rate that the power is demanded ie how quickly you pull on the "going up" lever vs where the TRT vector is tilted at the time of collective application.

25-30 deg NU, heavy, hot & humid (we have already heard tail wind component arguements) on termination with rapid collective input (high rate of demand) can/will result in RRPM decay. Combine this with checking level to the HVR attitude prior to dismount/disgorge = bunting and decaying the RRPM even further. If you're generous you would say a HEAVY Landing will be the result...........

"OR"

Maybe the TACTICS employed need refining and DECU's would only assist not FIX the problem.

Max

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Old 6th Aug 2007, 04:15
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The S-70A-9 when it came into service with the RAAF in 1988 then transfered to the Australian Army in 1990/91 was the most powerful advanced utility assault Helo in the world, the Aussie S-70 had the high output main xmissn from the Seahawk,Rotor brake, a rear avionics bay with access door (just on the M model 60 now), folding stabilator from Seahawk , Seahawk afcs systems and T700-701A-1 engines(the -1 is for fuel flow indication),Fuel dump,HIRSS and pilot seat blowers for hot climate (the envy of many other Blackhawk operators), and bloody useless sideways facing troop seats, ESSS, etc most of these features are only just going onto the UH60-M now 20 years later, our Blackhawks are still world class it's just the way we seem to operate them isn't!
of the 39 delivered we have had 6 crashes for 5 writeoffs ,4 of the 6 crashes were in Spec ops training and all of the crashes have been pilot error the helo has not been to blame in any of them, I have seen Norwegian Jaeger Kommando operating with Bell 412SP's and British and French Spec forces operating with 330's and the don't seen to fly beyond the Helo cpability,why do we!! the Aussie S-70's were having airframe cracks at about 2500 hrs that most other operators were getting about 4000hrs because of the way we operated them.
The S-70 is an extreamly powerful Helo both in engine and flightcontrol power during deck trials on the HMAS Tobruk in the early 90's it was almost impossible to over input controls and the test pilots said (RAAF and Navy) it had more flightcontrol authority than any other helo in the ADF and more the just about any other they had flown, and then I have seen pilots complain about T/R authority flying in New Guinea...... down wind approach into Mount Hagen(5500') I wonder why they have t/r problems!
And Fadec won't help the engines either ,if you pull the power in to late you will hit hard!! and if you have to much power you will over torque or overpitch.
As Twin Huey man said in another Blackhawk post the Blackhawk is a very powerful easy to fly helo and pilots get themselves into trouble when they fly beyond the helo something Kiowa, Huey ,330, and 412 pilos don't do as they know from scratch they are flying an a/c with limits something Blackhawk pilots forget.
I hope the Australian Army changes its attitude to the way it flies especialy the Spec Ops role because if they try and fly a NH-90 like a Blackhawk they will roll a lot more into balls as the NH 90 will not handle the abuse a Blackhawk has taken.

Last edited by Blackhawk9; 7th Aug 2007 at 02:39.
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Old 9th Aug 2007, 10:47
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BH9, sounds like you know just a bit about the BH, must say I can't find any flaws in your arguement. I would like to see a response from some of the crowd that do the flying we are hearing so much about though. Just to balance the arguement and to maybe suggest how much is rumour and how much is fact.

Is curious though that other countries that do Spec ops with helos don't seem to break them at this rate.

Is it your opinion chaps, that the media and 'transparency' here in Oz bring more of these issues to light than would find their way into the press in somewhere like say the UK, France or Norway. Or are we just throwing them around a bit too much?

Interested to hear your thoughts.

TW
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Old 9th Aug 2007, 14:24
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I think Blackhawk9 put it perfectly. The UH-60 is an excellent helicopter and very capable of doing many things, including flying aggressively in the ways that the Mega Force guys require. However, there is an excellent quote floating around amongst those who do the bullet dodging work: "Combat situations do not negate aerodynamic principals nor aircraft limitations" -- give a guy less than a year of by-the-book training (as militaries around the world do for their pilots) and put them in a helicopter that they have been told is the ferarri of the skies and load up a dozen of the meanest and most dangerous men in the world, then tell said pilot to do a hot maneuver to get the guys in, and you have a recipe for disaster.

I'm not sure how the Australians do it, but in the good ole American army, it is not uncommon for the total flight hours in the cockpit to be below 1500 and the cumulative years flying to be in the single digits... in combat, with a Mega Force team in the back, at night, in poor weather, chasing bad guys that are running or driving like crazy. All militaries have always had a poor understanding of the capabilities and limits of helicopters and the prerequisites so that they can perform tasks safely. While I doubt a 200 hour wonder would be doing shipborne special forces assaults in any military, seeing what they ARE doing at their experience level can begin to show the lower experience level that Militaries seem to feel necessary to do a given task, and it is that way across the entire spectrum of missions. If you're the biggest military in the world with a damn near unlimtied budget, you can compensate (at least a little) with good training and extensive recurrent training, but if your military doesn't have a budget up in the clouds, the chances of getting the people proficient and keeping them at their best is a very difficult task, especially for such a demanding mission.

Obviously I'm not saying the pilots in this situation fell into this category, but its very possible that they could have. That is how the big green machine sure seems to work.

Mike
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Old 9th Aug 2007, 15:23
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TwinHueyMan, your assertion that there's a lot of pressure on a pilot to perform with special forces types in the back is fair enough, but this statement:

"All militaries have always had a poor understanding of the capabilities and limits of helicopters and the prerequisites so that they can perform tasks safely."

is one of the most sweeping I've seen in a long time. Are you suggesting that you know how all military helicopter operators train and work, and that none of them understand the limitations of the machines they operate?
That's absolute bullshit, frankly. Have a think about what you're writing.
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Old 9th Aug 2007, 15:52
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My only complaint about the UH-60A fuel controls was that if you reduced power just before applying power (like rejecting a landing to a ship), the rotor RPM would droop considerably more than if power was applied from a steady condition.
Has anyone looked into that as a factor??
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Old 9th Aug 2007, 16:52
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Shawn,

You’re probably recalling the insidious nature of the A model transient droop, which is now covered in the manual. Under low power conditions, when the rotor goes high, the fuel controls trim the engines down. This occurs even if the pilot is pulling up on the collective and until the rotor returns to nominal. The result is significant transient droop under specific combinations of ambient conditions, loading and maneuver.

It helps to have a good understanding of the systems when venturing outside of “normal operations.”

I notice your tagline has you in Mojave. Working on anything fun?

Jim
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Old 9th Aug 2007, 18:02
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Hey Arm Out the Window:

""All militaries have always had a poor understanding of the capabilities and limits of helicopters and the prerequisites so that they can perform tasks safely."

is one of the most sweeping I've seen in a long time. Are you suggesting that you know how all military helicopter operators train and work, and that none of them understand the limitations of the machines they operate?
That's absolute bullshit, frankly. Have a think about what you're writing."

Sorry I wasn't clear about that. I believe that, by in large, military aviation has a good grasp on what their equipment can do. Some individual pilots may have misconceptions, but at a company level, the level of understanding within the unit is pretty high across the board. What I mean is that the "big army" has a less clear vision of what aviation can do for them. Units routinely ask a lot of aviation, mostly due to inadequate relationships between the ground pounders and the aviation units, and the general consensus of aviation units is to do whatever they can do to help the guys on the ground. There is nothing wrong with that relationship, but it could be a lot better and a lot safer. This goes from preparing a landing zone on up to questioning weather minimums and the time it takes to properly plan a mission. I'm sure most of us that fly for the green machine have experienced it, I know that I have on many occasions... and in the end, the job is to support the guys and girls on the ground, so we do the best we can given the circumstances... however that can get us into situations where experience is the best, if not the only, way of ensuring a safe completion of whatever it is they need us to do in the situation they have provided.

I fly in a medical unit, and a primo example of this the roadside pickup of wounded soldiers. There is no way we can give training to every unit we service on what we like and need them to do to keep us safe when we land on Route Whatever -- so when the call comes in, and the road has wires and ditches very close on either side, and dust, and poor security, uncleared, surrounded by locals, with infantry running all over the LZ and humvee headlights blinding your NVGs-- all of this which happens to be 1/2 mile from a beautiful landing zone at a secured base... the decision to put the wounded guys life on the line to move him or wait for them to make the landing zone better is a very difficult decision. Throw in a teaspoon of adrenaline and the mandatory compassion, and you've got quite the quandry to mull over in your brain, which woke up from a dead sleep about 10 minutes ago. The line between a very challenging but successful mission, and a crashed aircraft, is very thin... and the best ally on those nights is good old fashioned experience.

-Mike
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Old 9th Aug 2007, 20:35
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Thanks, TwinHueyMan - I did take your comments the wrong way, so sorry about the harsh response. Thought you were talking about the operators, not the customers!
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Old 9th Aug 2007, 23:47
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Dili Black Hawk

THM:
Throw in a teaspoon of adrenaline and the mandatory compassion, and you've got quite the quandry to mull over in your brain, which woke up from a dead sleep about 10 minutes ago. The line between a very challenging but successful mission, and a crashed aircraft, is very thin... and the best ally on those nights is good old fashioned experience.
As a former military pilot, I often saw that.
AOTH:
I liked your comment about ;
Thought you were talking about the operators, not the customers!
As a civilian pilot, I would call it "Commercial Pressure".
How do we solve the problem? Training, which costs money. After every situation, there is an investigation to establish blame.
Result:
We need "good old fashioned experience."
Which costs money.
Rant over.
C Alexander
SirVivr
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Old 10th Aug 2007, 00:32
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Why rely on rumours? The transcripts to the Board of Inquiry into last year's Blackhawk loss off Fiji are at:

http://www.defence.gov.au/boi/blackh...transcipts.htm

In the transcripts, there is much discussion on rotor droop (and some interesting confusion over what constitutes 'droop' vs the allowable operating RRPM limits).

The Dili Blackhawk accident is also discussed.

In my opinion, the transcripts support BlackHawk 9's posts to a 't'.
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Old 10th Aug 2007, 05:56
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"As a civilian pilot, I would call it "Commercial Pressure".
How do we solve the problem? Training, which costs money. After every situation, there is an investigation to establish blame.
Result:
We need "good old fashioned experience."
Which costs money.
Rant over."

Spot on.
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Old 11th Aug 2007, 10:57
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What I mean is that the "big army" has a less clear vision of what aviation can do for them. Units routinely ask a lot of aviation, mostly due to inadequate relationships between the ground pounders and the aviation units, and the general consensus of aviation units is to do whatever they can do to help the guys on the ground. There is nothing wrong with that relationship, but it could be a lot better and a lot safer.
There are many quotes in most of the posts on this thread and the Fiji one that could be used to say, hear, hear to.

I picked this one, as exemplifying the core issue that I have been pounding. To the others I congratulate the ability that you all exude. I think the quote above demonstrates that your concern is slipping by your ability to rectify it. I hope that you can change that.

I know nothing about a blackhawk, which must be obvious, except seeing some of them doing some damm silly things like, full auto's into red out conditions, when they were fresh in the livery of the flying kangaroo.

However I feel deeply about youngsters being thrust into potentially limiting conditions beyond their ability by "the system."

1200 hours is a benchmark that we used in the mustering industry. The same as the 300 hour mark in a F/W driver ego /testosterone phantom euphoria levels. Those were too half smart, well they copped a check ride that brought them back to base and built them for great things.

If those at the top don't budget for correct training or employment of those that know then that needs to be changed.
all the best
tet
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