PPRuNe Forums

Go Back   PPRuNe Forums > Aircrew Forums > Rotorheads
Forgotten your Username/Password?

Rotorheads A haven for helicopter professionals to discuss the things that affect them


Reply
 
Thread Tools
Old 9th Apr 2012, 19:00   #81 (permalink)
 
Join Date: Apr 2008
Location: UAE
Posts: 299
Quote:
At least a '53 would have hit upright (like the Lead V-22, Nighthawk 71 did), not inverted and ensuring that it would be unsurvivable. Below 800 feet or so, A-VRS is unsurvivable. Marana proved that.
If they "hit upright" but do not survive, I fail to see the benefit.

FH1100,
We are trying to get some "expert advise" from people with experience on the CH-53 (who in mass obviously disagree with you, but JD may legitimately have information not available to all with his Sikorsky Aircraft Corp. experience). I read your web site and congratulate you on making it through the trouble you had learning to hover on your way to your private license a couple of years ago.

Now let's get 'back on point' as you like to say for questions asked of you earlier. Once again, there are a number of questions posed to you that are still unanswered on this thread. Please respond to those anxiously awaiting your informed advise. Here are the questions pending your answers (scroll down about half way):
What's the latest news of the V22 Osprey?

thanks...
21stC
21stCentury is offline   Reply
Old 9th Apr 2012, 19:38   #82 (permalink)
 
Join Date: Nov 2006
Location: Pensacola, Florida
Posts: 500
21st Century, in your misguided zeal to defend the V-22 at all costs, you try to divert the discussion. If you honestly want to stay on point and add to this discussion, then why not address what we're talking about here, which is what I see as the biggest flaw of the V-22: a low-level encounter with A-VRS is simply not recoverable and therefore unsurvivable. I know, I know...all you have to do when you sense that you're experiencing A-VRS is beep those nacelles forward and fly away! I say: by the time you realize you're getting into A-VRS it will likely be too late because you've already aggravated it by making an opposite control input (as happened to Majors Brow and Gruber).

The rates of descent experienced by Brow and Gruber were not sustained; they were merely transitory as they tried to maintain position on their Lead aircraft, the other V-22 (which also crashed, only level). Anyone who thinks that they intentionally initiated a sustained RoD of 2000+ fpm at 800' is insane. But that has become the narrative of the blame-the-pilots-not-the-aircraft group. The problem with Brow and Gruber's V-22 was that once they started coming down, that one proprotor got into VRS and over she went. Would not have happened that way to a CH-53. Would. Not. Have. Happened.

No, I don't know how hard a CH-53 can hit vertically and still be survivable. But I do know that it's better for ANY aircraft to hit upright to allow the landing gear and structure to do the job it was designed for than to crash inverted. Or do you dispute *that*?

Yes, yes, we know that VRS of any sort is difficult to get into when you're trying to demonstrate it. Fact is, the conditions that make it happen are not easily or dependably reproducable - unlike, say, the stalling speed of an airplane wing. Trouble is, when plain-vanilla VRS does happen it usually catches pilots by surprise, like when they're busy doing other things. Even a fairly "easy" shallow-but-fast straight-in landing can put pilots in a "task overload" situation as we saw in the Afghanistan V-22 crash. What makes us think that a steep, circling, improvised, possibly downwind approach (due to conditions being different than planned) won't result in the same thing...only worse? And A-VRS is *much* worse!

Arguing over comparisons between helicopters and tilt-rotors as to relative rates of descent needed to excite VRS is useless and irrelevant. I've said it before and I'll say it again: Only V-22's can get A-VRS. And low-level A-VRS is unrecoverable and absolutely unsurvivable. Saying...praying...pleading...promising it won't ever happen again is just silly. It will. The fact that it has so far not happened yet is no guarantee that it won't, and you know it.

End of story.
FH1100 Pilot is offline   Reply
Old 9th Apr 2012, 20:04   #83 (permalink)
 
Join Date: Nov 2010
Location: Earth
Posts: 396
A suggested read for this topic for those who haven't seen it before, as there is a lot of misinformation flying around (no pun intended)

(i.e. a rotor experiencing VRS is not stalled)

https://vtol.org/store/product/the-n...state-3416.cfm
SansAnhedral is online now   Reply
Old 9th Apr 2012, 20:05   #84 (permalink)
 
Join Date: Apr 2008
Location: UAE
Posts: 299
FH1100,

Let's bring it back to reality -- in your misguided zeal to attack the V-22 at all costs, what's in question is your experience level to contribute responsibly and intelligently to this discussion to give a level of confidence to those of us reading your comments that you have some knowledge of the subject matter. The one good thing is that most of us on both sides of the discussion have a good laugh reading your comments.


Quote:
I read your web site and congratulate you on making it through the trouble you had learning to hover on your way to your private license a couple of years ago.

Now let's get 'back on point' as you like to say for questions asked of you earlier. Once again, there are a number of questions posed to you that are still unanswered on this thread. Please respond to those anxiously awaiting your informed advise. Here are the questions pending your answers (scroll down about half way):
What's the latest news of the V22 Osprey?
And as stated previously on another thread recently:
Quote:
Get on the Clue Train
Get on board, FH1100.
I am far from being a tilt-rotor proponent but your question apparently comes from ignorance of information that's been published in the trade press for about the last 25 years or so concerning the tilt-rotor's construction, i.e., the XV-15, the XV-22... Look, you can be against the tiltrotor all you want (again, I am myself), but try to make your objections from a position of knowledge rather than ignorance. Because as it is you're making our side look bad.
http://www.pprune.org/rotorheads/456...ltrotor-2.html

thanks...
21stC

End of Story
21stCentury is offline   Reply
Old 9th Apr 2012, 20:26   #85 (permalink)
 
Join Date: Nov 2010
Location: Earth
Posts: 396
End of story, FH? Hardly.

A Ferrari can easily overcome the kinetic friction of its extremely high performance tires, skid though a turn and into a wall. Its much easier to do this in a 500hp supercar than it is in a 200hp Hyundai. What can possibly be done to prevent this!??! We drive the vehicles appropriately, avoid entering a corner at high speeds (which is a relative term, high speed for the hyundai might be 80mph, the ferrari 120mph), and learn recovery from skidding by countersteering, braking, and modulating throttle. Do we only drive Hyundais to avoid crashes like these? No.

Quote:
Fact is, the conditions that make it happen are not easily or dependably reproducable
FH, more uneducated drivel from an aerodynamic layman like yourself exposes your own crusade against the V22, and is causing you to lean heavily on hypocritical critiques of 21stC's contributions. You claim comparisons to the 53 are irrelevant, after filling an entire post of the same.

I suggest you read the above white paper, and the multitude of flight testing reports linked elsewhere in this thread which have fully defined the very reproducible envelope of V22 VRS. In over 120,000 flight hours, no VRS incidents have been experienced. Will wonder's never cease, surely thats merely chance! Sure, it may happen again...if the aircraft is flown outside its well defined parameters. Just like flying a teetering rotor in a -1G maneuver....you sound like Mark Thompson hammering on "this fatal flaw".
SansAnhedral is online now   Reply
Old 11th Apr 2012, 20:20   #86 (permalink)
 
Join Date: Nov 2010
Location: Earth
Posts: 396
V22 Down in Morocco, no details yet

Two U.S. soldiers die in helicopter crash in Morocco | Agricultural Commodities | Reuters

U.S. soldiers wounded in Morocco crash: media | Reuters
SansAnhedral is online now   Reply
Old 12th Apr 2012, 08:42   #87 (permalink)
 
Join Date: Apr 2008
Location: UAE
Posts: 299
A Little More Information

Quote:
2 Marines killed in Morocco Osprey crash




By Gina Cavallaro - Staff writer
Posted : Wednesday Apr 11, 2012 18:08:58 EDT

Two Marines were killed and two severely injured in the crash of an MV-22 Osprey during a training mission in southern Morocco, the Marine Corps confirmed Wednesday.
The Osprey crashed in a military training area southwest of Agadir, Morocco, after taking off from aboard the amphibious assault ship Iwo Jima, said Capt. Kevin Schultz, a Marine spokesman at the Pentagon in Washington.
The four Marines were the only personnel aboard the Osprey at the time of the crash.
The aircraft was attached to the 24th Marine Expeditionary Unit, which deployed from Camp Lejeune, N.C., on March 29. Among the major subordinate units that belonged to the MEU was Marine Medium Tiltrotor Squadron 261, an Osprey unit out of Marine Corps Air Station New River, N.C.
The MEU is in Morocco supporting Exercise African Lion, an annual 10-day joint exercise with Royal Moroccan Armed Forces which is being overseen this year by the 14th Marine Regiment, a Reserve artillery regiment from Fort Worth, Texas.
The event was scheduled to conclude April 17, followed by 10 days of breakdown and redeployment. More than 1,000 Marines, and about 200 soldiers, sailors and airmen from across the U.S. are participating.
This year marked the first time the bilateral exercise included a MEU.
Further information about the crash was being withheld until the next of kin were notified, said Rodney Ford, spokesman for the U.S. Embassy in Rabat.
The cause of the incident was under investigation, according to a press release from U.S. AFRICOM.
Despite a rocky beginning for the Osprey more than 12 years ago with the deaths of 23 Marines in two crashes during testing, the Marine Corps has rated the MV-22 as effective in a combat environment, first fielding it in an operational capacity in Iraq in 2007.
An Air Force version of the Osprey, the CV-22, crashed in Afghanistan on April 9, 2010, marking the only fatal incident involving an Osprey in the war zone.
Two of the three cockpit crew members died attempting a night landing at a desert landing zone. Also killed were a soldier and a civilian contractor two of 16 passengers in the cargo compartment. The co-pilot survived.
The Associated Press contributed to this report.
2 Marines killed in Morocco Osprey crash - Marine Corps News | News from Afghanistan & Iraq - Marine Corps Times
21stCentury is offline   Reply
Old 13th Apr 2012, 12:38   #88 (permalink)
 
Join Date: May 2002
Location: Destin
Age: 66
Posts: 12,979
Facebook this morning had an ad by Bell claiming the Osprey has achieved 130,000 flight hours and has proven itself to be the safest aircraft in the Marine Inventory (or words to that effect).

How many fatal crashes so far?

Does one fatal crash per 30,000-40,000 flight hours seem a bit high ?
SASless is offline   Reply
Old 13th Apr 2012, 14:57   #89 (permalink)
 
Join Date: Nov 2010
Location: Earth
Posts: 396
Well SAS lets do the math...

Before yesterday:
Osprey serious mishap rate - 1.28 per 100,000 flight hours
Marine air fleet serious mishap rate - 2.6 per 100,000 flight hours

Even if they were only at 100,000, if you include the incident yesterday that would put them at 2.28, which is still lower than the fleet.

(But of course, it looks like your numbers are trying to include accidents that happened before the V22 was out of the prototype/testing stage or even deployed.)
SansAnhedral is online now   Reply
Old 13th Apr 2012, 15:25   #90 (permalink)
 
Join Date: May 2002
Location: Destin
Age: 66
Posts: 12,979
Sans.....just using the 130,000 hour figure used by Bell.....does that include all flight time from Test Flight 1? I am just asking the question....and using their data....so how many FATAL crashes have there been.....and you pick the benchmarks re flight time! What is the percentage of Fatal/Non-Fatal Accidents? If Bell and the Marine Corps PR folks want to throw out numbers....then let's see what they are based upon and how they arrive at their results.

Four Bell 212's I flew in Nigeria exceeded that amount of flight time....high time bird had either 37,000 or 41,000 hours alone....I know one had 37,000 as I flew its last Flight....and kept the Clock as a Souvenir.

It was sold off as scrap....and has been rebuilt and is flying again somewhere in Canada last I heard.

So 130,000 hours is not a whole lot of flight time in reality.
SASless is offline   Reply
Old 13th Apr 2012, 15:44   #91 (permalink)
 
Join Date: Apr 2008
Location: UAE
Posts: 299
Sas,

People in the tiltrotor community have died and been severely injured. It is likely that some who are close to them are PPRuners or will read this thread. Undoubtedly there are those on the anti side that will be smacking their lips in happiness and will try to use this to discredit the technology even before any information is forthcoming ignoring the loss of life. I don't think that you are one of them.

Now is the time to mourn the loss as we do in the helicopter community which is very much integrated with the tiltrotor community these days. Let's wait until some facts come forward in this recent fatal accident before using it in a pro/con debate.

thanks,
21stC
21stCentury is offline   Reply
Old 13th Apr 2012, 16:02   #92 (permalink)
 
Join Date: Nov 2010
Location: Earth
Posts: 396
Well here's a good overview

V-22 Osprey Crashed After Dropping Troops At LZ; Mechanical Failure Unlikely
SansAnhedral is online now   Reply
Old 13th Apr 2012, 16:34   #93 (permalink)
 
Join Date: May 2002
Location: Destin
Age: 66
Posts: 12,979
Quote:
"The fact that the Marine Corps and Air Force have not grounded the V-22 strongly suggests that something other than an aircraft malfunction was at fault here," a military officer who has participated in accident investigations said.
Clear day....near empty aircraft....over land.....and Pilot Error? This is going to be and interesting story. An aircraft destroyed and two Enlisted Crew members dead....let's see how this plays out.

21st....people die in Aircraft accidents...fact of life...and each one is a tragedy.

I firmly believe each one of these tragedies should be a learning experience....investigated to determine the cause....then apply the best measures possible to try to prevent similar occurrences. This forum is not the place for that investigation...that will be done by the USMC and US Navy with much interest in the results by the Air Force.

The good news on this one is two Pilots able to relate what happened as best they can recall, the Data/CVR Recorders will be recovered and analyzed, and there should be some witnesses perhaps. Unlike the USAF crash, there is a very good chance this one will provide some answers to what happened without any ambiguity as in the USAF crash.

Discussing these accidents is not Taboo.....otherwise we would never learn from them....that would be the worst loss of all.
SASless is offline   Reply
Old 13th Apr 2012, 17:45   #94 (permalink)
 
Join Date: Apr 2008
Location: UAE
Posts: 299
Quote:
Discussing these accidents is not Taboo.....otherwise we would never learn from them....that would be the worst loss of all.


Sas,

Discussing these accidents is definitely not 'taboo,' in fact it is an absolute necessity so that as many as possible can learn from the true facts of the event. But to postulate, make comparisons, or give pre-conceived predictions of what may have happened without the facts will not help any of us in the industry (helicopters and tiltrotors are now linked jointly at the hip with crossover on both the operations and maintenance side). Sadly that is going to happen from both the pro and anti sides within the industry no matter what we do, but the rest will wait to hear what really happened before passing judgment. Projecting our pre-conceived notions into what we think may have happened or throwing the accident into a pool of statistics before knowing the facts will not contribute to a true understanding of what actually happened and what the relevant repercussions will or should be.

Again the most important thing at this moment is the loss to families and friends suffered as a result of the accident. We all give them our thoughts and prayers, and after that hope to see a critical analysis of the accident in the aftermath as soon as possible.

thanks,
21stC
21stCentury is offline   Reply
Old 13th Apr 2012, 17:50   #95 (permalink)
 
Join Date: Nov 2010
Location: Earth
Posts: 396
Morocco hints strong wind caused U.S. aircraft crash | News by Country | Reuters

Quote:
"According to the parties concerned, strong wind appears to have caused the crash," Communication Minister Mustafa El-Khalfi told reporters in Rabat. "But the exact causes will be determined by an investigation that is under way," he added.
KUNA : Helicopter crash kills two US militants, injures others in Morocco - Military and Security - 12/04/2012

Quote:
The accident was caused by a fire that broke out in the aircraft
?
SansAnhedral is online now   Reply
Old 13th Apr 2012, 18:06   #96 (permalink)
 
Join Date: Aug 2009
Location: Texas
Age: 55
Posts: 3,016
Quote:
According to the parties concerned, strong wind appears to have caused the crash," Communication Minister Mustafa El-Khalfi told reporters in Rabat. "But the exact causes will be determined by an investigation that --
Not to get all semantic on a non-English speaker (the Communication minister), nor the reporter he is talking to ... but I'd hope that someone who covers aviation (reporter?) would understand the difference between "contributed to" and "caused" a crash. The politician might well not, or, the translation might have been rough.

To amplify:

I've flown in a lot of very crap weather, to include shooting approaches at minimums. Some other pilots/aircraft have crashed in weather close to or at mins, but I didn't. The weather contributed to my risk of a crash, and at times made my task of safe arrival a bit more challenging.

Likewise with high winds, when I've flown in them, particularly when in rotary winged craft when doing maneuvers near the edges of performance margins.

Does the weather (or wind) "cause" the crash, or "contribute" to it?

Will All Journos Reading This Thread Please Take Note of the Distinction?

Thanks.
Lonewolf_50 is offline   Reply
Old 13th Apr 2012, 19:37   #97 (permalink)
 
Join Date: May 2002
Location: Destin
Age: 66
Posts: 12,979
Quote:
But to postulate, make comparisons, or give pre-conceived predictions of what may have happened without the facts will not help any of us in the industry....
Who has done that?

Why the pro/con reference?

Are you suggesting there are only two views to be found here....one that always blames the aircraft (no matter the accident chain) or others who always blame the Pilots (no matter the accident chain).....or is there a third group who see accidents (of any aircraft type and model) as being a series of events that lead to a crash, with multiple causal factors with some being more critical than others?

Within a few posts there was an article that suggested it was not an "aircraft malfunction" which was patently premature.

I am on record as saying....."Lets see how this plays out.", and suggested we wait to hear what the Data/CVR recorders, surviving crew, and any witnesses have to say.

So far we have one vote against an aircraft malfunction, one input saying high winds, one saying a fire of some sort, and one saying crew error. All are not from any credible source at this time.
SASless is offline   Reply
Old 14th Apr 2012, 06:00   #98 (permalink)
 
Join Date: Apr 2008
Location: UAE
Posts: 299
Quote:
"But to postulate, make comparisons, or give pre-conceived predictions of what may have happened without the facts will not help any of us in the industry...."

Who has done that?
Answer:
Quote:
So far we have one vote against an aircraft malfunction, one input saying high winds, one saying a fire of some sort, and one saying crew error. All are not from any credible source at this time.

Quote:
Why the pro/con reference?
Answer:
Look at every page of this thread...
21stCentury is offline   Reply
Old 14th Apr 2012, 12:13   #99 (permalink)
 
Join Date: May 2002
Location: Destin
Age: 66
Posts: 12,979
One must separate the Wheat from the Chaff.....amongst all the traffic noise there is something to be heard.
SASless is offline   Reply
Old 14th Apr 2012, 12:50   #100 (permalink)
 
Join Date: Apr 2008
Location: UAE
Posts: 299
That is very true. And of course this is a "Rumor Network," so information coming in "from the field" will likely be inaccurate at first, but will provide some pieces to the puzzle as the true facts come together. Jumping to conclusions using early information that all too often turns out to be inaccurate is where a potential problem lies.
21stC
21stCentury is offline   Reply
Reply
 
 
 


Thread Tools


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT. The time now is 15:06.


vBulletin® v3.8.7, Copyright ©2000-2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
1996-2012 The Professional Pilots Rumour Network