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ChocolateJesus
10-13-2003, 08:00 PM
Everything I've heard said it was due to his experimental ultralight airplane.

But was it ever determined to be pilot error, mechanical failure, weather or a little bit of everything?


CJ

PhilAlex
10-13-2003, 08:09 PM
tHE plane he was flying, was designed by a veritable genius of aviation, Burt Rutan.

So, I doubt it's a design error.

Since witnesses saw it STALL, rather than, say, fall apart, I'd likely say pilot error.

But who knows.

N9IWP
10-13-2003, 08:20 PM
Full report:
http://avweb.com/other/ntsb9905.html

Brian

Tuckerfan
10-13-2003, 08:23 PM
IIRC, the FAA determined that the problem was caused by the modifications made to the plane made by the previous owner. He put the switch to switch from one fuel tank to the other in a location inconvienent for the pilot (behind the pilot's seat), so Denver either couldn't get to the switch in time, or he bumped the controls while he was trying to flip it.

Rabid_Squirrel
10-13-2003, 08:28 PM
Trite/snarky answer: The real cause was gravity.

Extraneous
10-13-2003, 09:15 PM
Sneaky suspicion:

bird strike. According to local rumor, the body was ID'd by fingerprints, and the Long EZ is a bathtub with a 1/8" plexi canopy, and being a canard, is next to impossible to stall, and barring deliberate pilot action (read: suicide), getting a Long EZ to strike water nose down would be a trick - so water probably did not shear the canopy - a pelican, OTOH, encountered at 200 mph, will go through a 1/8" plexi canopy real well.

I suspect the NTSB wanted to soften the blow for fans, and since it was not a situation likely to be repeated, absolute accuracy is not needed.

And, the re-location of the fuel valve is not an issue - the FAA certified that device as being an airplane - and the pilot is expected to be able to safely pilot any airplane he/she decides to fly. If the pilot is physically unable to reach the fuel valve, he should not fly that airplane.

From here we could go into the question of who is the manufacturer of a homebuilt (hint: it wasn't Burt Rutan, or anybody else at RAF) and who gets to decide things like where to place the fuel valve (hint: the manufacturer).

Berkut
10-13-2003, 09:41 PM
Originally posted by PhilAlex
tHE plane he was flying, was designed by a veritable genius of aviation, Burt Rutan.

So, I doubt it's a design error.That's only if it's built according to the design. It wasn't.
Since witnesses saw it STALL, rather than, say, fall apart, I'd likely say pilot error.

But who knows. The canard design, if built and loaded correctly, is extremely stall resistant.

Broomstick
10-13-2003, 09:48 PM
I'd say smacking into the water at a high rate of speed was what killed him.

Having started in the homebuilt segment of aviation, it's been a chronic problem that pilots with lots of experience in more conventional aviation frequently do not appreciate just how different some of these aircraft are. His "transition training" mentioned in the NTSB report linked was, in my opinion, inadequate. The fastest I ever transitioned to a new airplane was 3 hours - but that was moving from one airplane to one very similar. Usually, I take 5-10. Yes, some people can transition faster. Chuck Yeager took 1-2 hours to transition to an ultralight. Hey, if 2 hours is required for General Yeager I'd say that's a rock-bottom minimum. OK?

Again, this was an airplane of unusual design. Good design - Rutan designs very good aircraft (and currently he's designing a spaceship) - but it's not like the Cessnas/Pipers/Beech/whatever of more conventional, factory-built aircraft. And homebuilts are infamous for builder/owner modifications. No two - even two built from the same plans - are ever quite the same. Which is another thing to be wary of - putting a fuel selector in an unusual place is hardly the most extreme modification I've seen in a homebuilt. A pilot of conventional aircraft stepping into a homebuilt with quirks can have some very unpleasent surprises.

Now, about that fuel selector. Heck, lets talk about that whole fuel indicator system. It doesn't sound real, um... precise. Which isn't that unusual. Even in conventional airplanes I visually check the fuel, use dipsticks to measure quantity, and otherwise confirm how much is in there independent of the fuel gauges - because sometimes the gauges are wrong. In a homebuilt, with a float-indication system, particuarly one that (apparently) was not calibrated, it's even more important to check and doublecheck your fuel levels. Did he do this? I'm not sure. Did he take off on the tank with the most fuel?

You know, if I was faced with a fuel selector in such an awkward position I think I'd tank up on both sides and only change the switch on the ground. He was already planning to have the fuel selector moved to a more accessible position, which indicates he didn't like the set-up, either.

Another point: An E-Z is a very light airplane. Even if it was very stable in the air while flying, an adult man shifting his weight in the cockpit was probably enough to cause a significant shift in flight attitude (I've been know to steer a Cessna 150 - an airplane heavier than an E-Z - merely by shifting my weight side-to-side or front-to-back while in my seat. And I'm a small woman) From the sound of it, the "autopilot" wasn't terribly sophisicated. Could probably hold things straight and level with the pilot sitting reasonably still - the pilot twisting 90 degrees, and maybe leaning on a rudder pedal as well would probably exceed the ability of the autopilot to hold things steady. Which was MY first thought, even before I read the full report.

To sum up: It is the opinion of this pilot, with some experience in ultralights, homebuilts, and small general aviation (although I wouldn't call myself an expert) that

1) John Denver's death was caused by smacking into the ocean surface at high speed - i.e. blunt force trauma - which was caused by

2) Unfamillarity with the quirks of the airplane he was flying due to inadequate transition training, leading him to perform actions in the cockpit during flight that, in this particular airplane were far more hazardous that the pilot realized.

Weather was NOT a factor. I'd say mechanical failure was not a factor, but a poorly designed modification was certainly a contributing factor. Mainly, though, it was the action of the pilot. That is, pilot error.

I'd like to emphasize that switching fuel tanks in an E-Z with a fuel selector in the designed location is far less hazardous.

But just a couple points for accuracy's sake:

ChocolateJesus, an E-Z is not an ultralight. It is four times heavier than the maximum allowable weight, carries three times as much fuel as an ultralight is permitted, and is about twice as fast as the maximum speed permitted with the originally designed engine. With a heavier, more powerful engine (such as we're discussing here) it would be faster still.

PhilAlex, for all practical purposes a canard can NOT be stalled. Oh, I suppose you could come up with some weird, bizarre circumstance in which it could be called "stalled", but that didn't happen here. You can put them into a very steep dive, and being "slick" aerodynamically they can easily build up such speed that you can not recover from such a dive when low to the ground (or water). But he most certainly neither stalled nor spun in that aircraft.

All that said, for an experimental homebuilt design they are pretty good, with a decent safety record for the category. They are not considered a beginner's airplane, but then John Denver was not a beginning pilot, either. He actually had more training and experience than most of the E-Z pilots I currently know or know of. My home field had an E-Z pilot who bought his E-Z when he had only about 100 hours total and the man quite successfully flew it thousands of miles and about 50 hours before he had to make an emergency landing after dark on a road and elected to hit the lightpole instead of on-coming traffic. In that case, the pilot survived although he spent some time in the hospital. I might also emphasize that this gentleman took, if I recall (and don't quote me on it) something like 15-20 hours of transition training in that airplane.

It's not just total time and experience but also experience in the particular aircraft that counts. Sure, Mr. Denver flew his own Lear Jet - that does NOT qualify him to fly an E-Z safely without some instruction. As I said, even Chuck Yeager, who has the incredible distinction of being both "old" and "bold", took transition training with an instructor before stepping into the unconventional arena of the lightplane and ultralight world of flight. Likewise, although I knew how to safely fly an ultralight when I walked into a general aviation airport and announced I wanted to earn a license, my prior experience was of only limited use in conventional general aviation.

Richard Pearse
10-13-2003, 10:11 PM
Originally posted by Extraneous


I suspect the NTSB wanted to soften the blow for fans, and since it was not a situation likely to be repeated, absolute accuracy is not needed.


I suspect that you have no clue what you are talking about. I suspect that the NTSB has something approximating zero interest in John Denver's fans and what they think or feel. I suspect that it is a situation that may well be repeated, if it happens once, it can happen again. Finally, I suspect that absolute accuracy is vital.

Berkut
10-13-2003, 10:11 PM
Originally posted by Extraneous
Sneaky suspicion:

bird strike. According to local rumor, the body was ID'd by fingerprints, and the Long EZ is a bathtub with a 1/8" plexi canopy, and being a canard, is next to impossible to stall, and barring deliberate pilot action (read: suicide), getting a Long EZ to strike water nose down would be a trick - so water probably did not shear the canopy - a pelican, OTOH, encountered at 200 mph, will go through a 1/8" plexi canopy real well.

I suspect the NTSB wanted to soften the blow for fans, and since it was not a situation likely to be repeated, absolute accuracy is not needed.The notion of the NTSB falsifying a report to "soften the blow for fans" is a little ridiculous, don't you think? The man is dead, no matter what the cause.
And, the re-location of the fuel valve is not an issue - the FAA certified that device as being an airplane - and the pilot is expected to be able to safely pilot any airplane he/she decides to fly. If the pilot is physically unable to reach the fuel valve, he should not fly that airplane.How does the fact that the FAA issued it an experimental airworthiness certificate make the fuel valve a non-issue? Experimental aircraft are not certified to the standards set forth in FAR part 23.

From here we could go into the question of who is the manufacturer of a homebuilt (hint: it wasn't Burt Rutan, or anybody else at RAF) and who gets to decide things like where to place the fuel valve (hint: the manufacturer). Adrian D. Davis, Jr.

Broomstick
10-13-2003, 10:24 PM
Originally posted by Extraneous
According to local rumor, the body was ID'd by fingerprintsWell, yeah, rumor had it he was decapitated and they found the body before the head. So it's either fingerprints, toeprints (if available), or DNA.

and the Long EZ is a bathtub with a 1/8" plexi canopyUm, it's a fiberglass shell. It's thinner than a bathtub.

being a canard, is next to impossible to stall, and barring deliberate pilot action (read: suicide), getting a Long EZ to strike water nose down would be a trickHardly. You don't have to stall an airplane to put it into a steep dive. They will nose down, they will enter steep spirals, and do pretty much anything BUT stall.

so water probably did not shear the canopy - a pelican, OTOH, encountered at 200 mph, will go through a 1/8" plexi canopy real well.OK. I have seen the actual wreck of an actual E-Z that crashed two blocks from my home (the above-mentioned person from my home airport) I also saw the wreck - what was left of it - after the NTSB turned it over to the salvagers. An E-Z doesn't break, it shatters. I have no trouble with the idea that it could break apart in a water impact. Also, if the pilot's restraints failed to hold a human body could shear off a canopy just as easily as a pelican.

One drawback to the E-Z airplanes is that they aren't very "crashworthy". They provide almost no protection to the pilot in an accident. Granted, no one plans to have an accident, but E-Z's are worst than most small planes in this regard.

I suspect the NTSB wanted to soften the blow for fans, and since it was not a situation likely to be repeated, absolute accuracy is not needed.WHOA! That I have trouble with. The NTSB is not perfect, but I don't think they'd "soften the blow". It's pretty damning to say he screwed up - which is essentially what they did say.

Why would the NTSB have any care about what Denver's fans think? They certainly didn't cut any corners or soften any blows for JFK, Jr. If anything, they'd show less mercy to a celebrity because it offers them a chance to educate other pilots not to do this, that, or the other less than wonderful thing.

And, the re-location of the fuel valve is not an issue - the FAA certified that device as being an airplaneThe rules are different for homebuilts. Anything registered under the experimental homebuilt category is required to have a placard in full and easy view of both pilot and passenger(s) (if there is a place for a passenger) stating that the aircraft is amateur built and does NOT necessarially conform to FAA standards. Yes, there is an inspection process but there is NO formal testing program for these airplanes and they are very much "fly at your own risk".

and the pilot is expected to be able to safely pilot any airplane he/she decides to fly. If the pilot is physically unable to reach the fuel valve, he should not fly that airplane.Seems straightforward, doesn't it? Fact is, he COULD reach the fuel selector, he just couldn't move it without getting into an unsafe position.

And sometimes you have to futz with things before you work out how you can reach and manipulate everything. I've spent a half an hour adjusting seats, rudder pedals, restraints, and so forth in order to determine a position from which I can operate everything with maximum ease. I've also used booster cushions when necessary. That's part of the transition to a new aircraft - working out you're best position in the cockpit. Yeah, sometimes you find out that the airplane isn't a good fit. If you can't come up with a way to compensate yeah, you should elect not to fly it - but again, Denver could reach the control, he just couldn't manipulate it safely. Which he should have been able to determine on the ground. The onus is on the pilot to know how to manipulate everything in the cockpit before he takes off.

Sam Stone
10-13-2003, 10:30 PM
I think Broomstick nailed it. This was a human factors accident. I wouldn't call it 'pilot error'. Nor would I call it 'design error'. The fuel selector was certainly placed in an awkward position. This is not necessarily a fatal flaw - If the designer knew what he was doing, knew the limitations of the design, and took steps to minimize the drawbacks of the location (for example, by practicing fuel management such that he never had need to switch tanks at low altitude), it might be a manageable issue.

But when you sell the airplane to a 3rd party, who may not be intimately familiar with the issues such a design creates, the potential for disaster comes along.

It sounds to me like Denver tried to switch tanks low and slow, and while engaged in that activity neglected to fly the airplane. Perhaps he thought it was trimmed up for level flight, and never considered the effect of a Cg change from moving around in the cockpit. Perhaps he was so used to slower, draggier airplanes that he just trimmed it up and then bent around to change tanks, confident in the notion that if the airplane went out of trim he'd feel it, or hear the added wind rush, or whatever. He underestimated just how quickly a slick airplane like an EZ can dive if it falls out of trim, and paid with his life.

Extraneous
10-13-2003, 10:35 PM
Short of a bird strike, how exactly did a Long EZ get its canopy sheared - the only explanation consistent with fingerprint ID - for the water to have done it, the plane would have struck nose-down or inverted - real difficult for a canard, short of a deep stall.

The fuel valve is not an issue because it did not change location during the flight - the pilot took it upon himself to fly an airplane with the fuel selector where it was during pre-flight. This is a red herring to try to mitigate your basic "pilot error".

It's not likely to happen again, because the plane with the re-located valve was destroyed, and I doubt if too many Long EZ's were built with the valve in the over-the-shoulder location. If any others were, I suspect simply everyone owning/operating them is aware of the location of the valve, and can safely operate it in-flight.

Fuji Kitakyusho
10-13-2003, 10:46 PM
What REALLY caused John Denver's death?

Karma.

Berkut
10-13-2003, 10:52 PM
Originally posted by Extraneous
Short of a bird strike, how exactly did a Long EZ get its canopy sheared - the only explanation consistent with fingerprint ID - for the water to have done it, the plane would have struck nose-down or inverted - real difficult for a canard, short of a deep stall.You don't think hitting the water at 200mph would shear the canopy off? In almost any attitude?
The fuel valve is not an issue because it did not change location during the flight - the pilot took it upon himself to fly an airplane with the fuel selector where it was during pre-flight. This is a red herring to try to mitigate your basic "pilot error".If the fuel valve didn't change position during the flight, it probably means he was unsuccessful at switching tanks. Doesn't mean that he didn't die trying.
I suspect simply everyone owning/operating them is aware of the location of the valve, and can safely operate it in-flight. John Denver couldn't.

Extraneous
10-13-2003, 11:33 PM
John Denver couldn't.


And he's dead, and the airplane destroyed - again, there is no likelyhood of a repeat of the incident - hence, there was no issue relating to other operators - no reason for an AD - hence the NTSB could shave the report for whatever reason(s). e.g. bury the fact that he was decapitated by a birdstrike.

And no, given the design of the Long EZ, I do not believe it possible for any water landing to have generated sufficient force to shear the canopy and the head of the pilot - that bathtub is a very sturdy structure - and even if it had hit with enough force to kill, the head would have remained intact - unless nose-down or inverted. A birdstrike is much more likely.

Richard Pearse
10-14-2003, 12:46 AM
Originally posted by Extraneous
And he's dead, and the airplane destroyed - again, there is no likelyhood of a repeat of the incident - hence, there was no issue relating to other operators - no reason for an AD - hence the NTSB could shave the report for whatever reason(s). e.g. bury the fact that he was decapitated by a birdstrike.

If the NTSB followed this line of reasoning with other accidents then there would be no accident investigations:

"Well look here Bob, the crew are dead and it looks like a particular set of circumstances caused this accident, it won't happen again, no point doing an investigation."


And no, given the design of the Long EZ, I do not believe it possible for any water landing to have generated sufficient force to shear the canopy and the head of the pilot - that bathtub is a very sturdy structure - and even if it had hit with enough force to kill, the head would have remained intact - unless nose-down or inverted. A birdstrike is much more likely.

We're not talking about a "water landing" here, we're talking about high speed impact. It can and does cause significant damage.

An experiment you might like to try is to go flying in an aircraft and let go of the controls, start fidling around with something behind you, don't look where you're going or what the aircraft is doing. Chances are, the aircraft will gradually enter a steep high speed spiral dive. An impact at speed with ground or water will cause severe damage to aircraft and occupant.

I'm curious, do you actually know anything about the subject? Cause a lot of other people here who do, seem to disagree with you.

buckgully
10-14-2003, 01:16 AM
There's an interesting Ask Tog article about the fuel tank selector issue:

http://asktog.com/columns/027InterfacesThatKill.html

Also, from the NTSB report:

The Safety Board examined the recovered wreckage for evidence of a possible bird strike. There were no leading edge canard or wing sections intact. The canopy was destroyed, and only fragments of the Plexiglas were recovered. Bird feathers were found commingled in the recovered wreckage. The curator of the local Museum of Natural History was asked to view the feathers during the wreckage examination. A seat cushion determined to be from the accident airplane was found torn open. According to the cushion material tag, it was filled with goose feathers; however, the curator also found duck feathers in the cushion. The cushion feathers matched the ones found commingled with the wreckage.

PhilAlex
10-14-2003, 02:43 AM
Not meaning to Hijack the thread, but what's the official word on the JFK crash? I keep hearing spiral dive, but what lead up to that?

Extraneous
10-14-2003, 03:26 AM
Spatial disorintation - confusing the city lights, reflections of city lights on water, and stars on a clear night - a classic "don't go there" in pilot training materials - your eyes have three sets of lights umongst which to find an airport - if you guess high or low, you die.

Nanoda
10-14-2003, 04:18 AM
Plus he wasn't instrument rated. I'm told that trying to use them, even if you're an experienced VFR pilot is dangerous. They don't call it a death spiral (http://vickivt.com/vicki/v178seconds.htm) for nothing.

Although I'm frankly surprised you believe the NTSB's report on JFK (http://airsafe.com/events/celebs/jfk_jr.htm), yet not the one on John Denver. Personally, the NTSB is one of the few U.S. gov't institutions I still trust.

Cardinal
10-14-2003, 04:18 AM
Once again, the people with actual experience in the subject get shouted down by the ones with a pet theory.

Broomstick
10-14-2003, 06:16 AM
>sigh<.... off to fight some more ignorance...

Originally posted by Extraneous
And he's dead, and the airplane destroyed - again, there is no likelyhood of a repeat of the incident Why not? Hey, the experimental in homebuilt experimental aircraft means just that - experimenting. There is absolutely no law or regulation forbidding the builder of such an airplane from making extensive deviations from the original design either while building it or later, after construction. For that matter, there is a person just over the state line from me who designed and built an airplace from scratch (it's a pretty good one, too, called a "Breezy") without the aid of an "expert". He's been flying it safely for about 30 years now. In fact, that airport has a good-sized group of amateur builders, a couple of whom I've flown with. You can go there, see 4 or 5 RV-6 kit planes lined up, and if you start looking you start seeing each and every one seems to have something significantly different - a different shaped rudder, or a different set to the landing gear, or a different canopy construction...

Oh, about that Breezy - do NOT get it into a full stall unless you're at least 8000 feet - it takes at least a half mile to recover it to normal flight. Why? I don't know. But it does. Neither does the designer. Other than that, it behaves pretty much like a convetional airplane. See, experimentals can bite you like that - perfectly normal until you hit a particular weirdness.

There is absolutely nothing to prevent another pilot from building an E-Z today with the fuel selector in a different location than Rutan intended. Next time, it might be overhead, or on the right. Would be pretty dumb to do that, but the FAA will allow you to kill yourself in an airplane - their main concern is that you not kill anyone else in it or with it.

hence, there was no issue relating to other operators - no reason for an ADHomebuilts don't have ADs. Mainly because each one is unique.

hence the NTSB could shave the report for whatever reason(s). e.g. bury the fact that he was decapitated by a birdstrike.WHY would they do this? What possible motivation would the NTSB have to deny a birdstrike? This makes zero sense, unless you're preposing a seabird conspiracy. Are you?

And no, given the design of the Long EZ, I do not believe it possible for any water landing to have generated sufficient force to shear the canopy and the head of the pilot - that bathtub is a very sturdy structure - and even if it had hit with enough force to kill, the head would have remained intact - unless nose-down or inverted. A birdstrike is much more likely. Have you ever seen an EZ up close? Touched one? Maybe even sat in one?

I've helped pull one out of a hanger and helped the pilot pre-flight and set up to fly. I not only saw the same plane after it crashed, I handled some of the pieces. (Charming conversation in the hangar - "Zeke, you think we can salvage this seat belt?" "Naw -- we'll never get all that blood out of it...")

Let's start with a very basic concept - an E-Z travels fast. Landing speed is around 100-110 mph (large variation because, being homebuilts, they vary a lot) - that's after it has slowed down from cruise. The guy who smashed his up in my area had already landed and was probably under 100mph when he wrapped it around the light pole. Fiberglass may be strong, but the shell on an E-Z is thin to keep the weight down and is there more for streamlining purposes than anything else. The fuselage, as I said before, shattered. We're not talking about something as sturdy as a boat hull. When getting into a small plane of this sort you want to step carefully because if you don't you can and will punch through the skin of the airplane.

Now, Denver's plane was in flight, well over 100 mph even if he was "low and slow" in the traffic pattern. Hitting a solid object with that plane in flight (and, at those speeds, water is more solid than liquid for impact purposes) would guarantee the fiberglass body would break up. When it does, it breaks up into very sharp-edged pieces. For our local wreck, the salvagers handling the fuselage fragments wore heavy gloves to prevent serious cuts - hitting an edge like that would be like falling on a meat cleaver.

Now, the airplane doesn't care which way it's nose is pointed. There is no magically ground-detecting wing. If it can fly straight and level at 150 mph (as an example) there is no reason it won't happily fly 150 mph (and then some!) with the nose pointed straight down towards the center of the earth. Add an engine and some gravity you can build up a fearsome rate of speed in a very short time. Any airplane can be pointed nose down and generate enough speed - without a stall - to physically rip the wing off the airplane. This can be done even with a glider, that is, without any engine at all you can use gravity to build up enough speed to destroy your airplane. An airplane is an inanimate object - it does what you tell it to, even if that's not what you intend. Denver didn't have to stall to crash - he only had to put the wrong control input in, get the nose pointed down, and do it so low he simply had no time to fix the problem.

Originally posted by Extraneous
Spatial disorintation - confusing the city lights, reflections of city lights on water, and stars on a clear night - a classic "don't go there" in pilot training materials - your eyes have three sets of lights umongst which to find an airport - if you guess high or low, you die.Get your facts in order. Yes, spatial disorientation is the official cause of JFK, Jr.'s death. But it was NOT a clear night! It was foggy, misty, and hazy, with minimal VFR visilities (3-5 mph) at best.. There was no starlight or moonlight to reflect, and only the distant lights of Martha's Vineyard to see - if that.

Originally posted by Nanoda
Plus he wasn't instrument rated. I'm told that trying to use them, even if you're an experienced VFR pilot is dangerous.Yes, it is. Life expectancy of a pilot without instrument training flying into instrument-requiring conditions is under three minutes.

VFR pilots are given minimal training in this sort of flying, with the idea that it might save a life to know something, and it has, but a lot of people have been killed over the year by harmless-looking white fluffy clouds. Me, the time I screwed up and found myself in this situation I opted to land in someone's backyard rather than continue the flight.

Flying_Monk
10-14-2003, 06:41 AM
I heard he was killed by a 1920's-style....oh, never mind.

flodnak
10-14-2003, 06:55 AM
Originally posted by Rabid_Squirrel
Trite/snarky answer: The real cause was gravity. It's not the fall that gets you, it's that sudden stop.

Johnny L.A.
10-14-2003, 08:49 AM
I know it's poor form to post without reading the entire thread, but I'm going to do it.

I also didn't read the whole NTSB report. However, I did read this part:
The National Transportation Safety Board determines the probable cause of this accident was the pilot's diversion of attention from the operation of the airplane and his inadvertent application of right rudder that resulted in the loss of airplane control
I read a letter in a flying magazine from a Long-EZ pilot. IIRC, he had the fuel selector located in the same place as the crash airplane. He said that the act of twisting the seat caused him to inadvertantly press on the right rudder pedal. This resulted in putting the aircraft into an unstable position. Obviously, he was able to recover. But he had power. From what I read not long after the crash, it seems as if this is the likely scenario: The engine suffered fuel starvation and left the aircraft without power. Denver reached around to switch tanks. In doing so, he inadvertantly pressed the rudder pedal. This yawed the aircraft and put it into an unusual position. Without power, Denver was unable to recover from the unusual position. I'll read the NTSB report after I get some caffeine in me.

Sam Stone says that was a "human factors error". I still lean toward pilot error, since a pilot should always insure there is enough fuel in the aircraft for the completion of his flight.

handy
10-14-2003, 11:07 AM
His plane went down right next to one of my surf spots here in the Pacific Ocean not far from land. Alot of people think it went down near Lover's Point, but actually it was near Asilomar blvd. I have to agree with Broomstick that he flew into the water at a high rate of speed, but was there water in his lungs? Wouldn't the fact he was under water be a factor?

Johnny L.A.
10-14-2003, 11:20 AM
but was there water in his lungs? Wouldn't the fact he was under water be a factor?
Not if his head was ripped off. The autopsy showed that he died of blunt trauma. I doubt he would have been able to take a breath, putting water in his lungs.

A note about Long EZ (and VariEze -- pronounced "very easy") construction. The are built much like surfboards. There is a foam core sandwiched between layers of fiberglass. This results in a strong, lightweight structure that is said to be easier to work with than aluminum. I have a video in storage that I got at RAF that demonstrates the strength of the structure. A canard was built, half of it in the foam/fiberglass construction and the other half in the traditional aluminum construction. Burt Rutan and his test pilot and co-builder (whose name escapes me at the moment) supported it on cinder blocks and jumped on it. The aluminum section was smashed. Then they put the foam/fiberglass construction on the blocks and they both stood on it, bouncing a little. It remained intact.

Broomstick is right though, that the airframe itself is like an egg shell. It's very strong, but once it breaks it can shatter.

I went back and read the NTSB report. It said that the calculated CG was at 110 inches. Scaled Composites says that the aft limit was 103 inches (although they tested it at 104). In an aft-CG situation, an aircraft may become unrecoverable in a stall. Now, a Long EZ is not prone to stalling; it was designed not to stall. But an aft-CG situation combined with an inadvertant deflection of a control surface while the pilot is pre-occupied by a sputtering engine is a recipe for disaster, which was to be demonstrated.

paperbackwriter
10-14-2003, 12:43 PM
Far be it from me to continue a hijack, but I wanted to emphasize something Broomstick said:

Originally posted by Broomstick
<snip>Get your facts in order. Yes, spatial disorientation is the official cause of JFK, Jr.'s death. But it was NOT a clear night! It was foggy, misty, and hazy, with minimal VFR visilities (3-5 mph) at best.. There was no starlight or moonlight to reflect, and only the distant lights of Martha's Vineyard to see - if that.
<snip>

I was staying at a hotel on the water on Long Island Sound (Water's Edge in Westbrook, CT, FTR) the night JFK Jr.'s plane went down. I remember waking up to the sound of a CH-47 flying low and slow along the coast. It wasn't until around noon that I found out why.

That evening, my wife and I were walking around the grounds. Although there weren't any clouds above, there was a thick haze over the water. That haze persisted until well into the late morning. As two data points, a small island about 100 yards offshore that I was later able to wade to was not visible from shore that night or in the morning. Also, the various aircraft (the CH-47 was only one of about 5 military ones I saw that AM) that flew overhead were very difficult to make out. The offshore haze definitely obscured them and extended for some distance upward.

This is all corroborative to the Meteorological Information section of the NTSB accident report (http://ntsb.gov/NTSB/brief2.asp?ev_id=20001212X19354&ntsbno=NYC99MA178&akey=1). I thought that a personal perspective might be appreciated in this context.

Jinx
10-14-2003, 01:29 PM
Originally posted by PhilAlex
tHE plane he was flying, was designed by a veritable genius of aviation, Burt Rutan. So, I doubt it's a design error...

I just wanted to comment that the designer may have nothing to do with the engineering of said plane. Afterall, didn't McDonnell Douglas take their lumps for the DC-10 design, for example? Now, is it a faulty design, or is it poor engineering? In some cases, these two words may be one and the same depending on just how far the designer takes a design into production. Consider Frank Lloyd Wright's dream designs, but someone has to actually build it and make it work. In short, fauty design could refer to the actual construction, too. If it were a faulty weld holding an airframe together, for example, it is possible that the weld called out on the blueprints was not the right choice OR the welder did not perform the welding job up to standards.

Splitting hairs, but even the greatest genius can be sunk by this!
- Jinx

j.c.
10-14-2003, 01:37 PM
For those who support the seabird conspiracy theory, I spoke with a few pilots after Mr. Rocky Mountain died, and they all said, best I can recall, exactly what Broomstick says. Being professional airline pilots former military gods, they tended to be a little more harsh.

Saltire
10-14-2003, 02:21 PM
The Onion reported that significant amounts of sunshine were found in Denver's system, in and around the area of his shoulders. The medical examiner said the levels were more than enough to have made him high.

handy
10-14-2003, 06:22 PM
Here is a weird page about it, hope no one tosses their salad:
http://findadeath.com/Decesed/d/John%20Denver/john_denver.htm

"They scooped up what they could find in multiple garbage bags, but what was left weighed only 128 pounds. Here's a list of what ended up forever fish food:

His brain, his teeth, his eyes, for that matter, 75% of his head was missing. Also gone were his right hemipelvis, and right thigh, one lung and his gallbladder. His left arm was missing, but they found it an hour or so later."

Broomstick
10-14-2003, 07:59 PM
Thank you handy for that Gratuitous Gore post. Where's my barfing smiley? We really need on for this crowd.

Personally, I thought "his head was ripped off" was plenty explicit enough, I really did not need an organ by organ recitation of missing body parts. Couldn't you have just stopped with the link? Maybe used a spoiler box?

BTW - just to get back somewhat on track - perhaps Sam Stone or someone else with a little better grasp of aerodynamic engineering might wish to explain why a bunch of us out here are saying things like "you can't stall a canard." For that matter, you might want to mention we're not talking about engines stalling but wings. And what a canard is As a pilot, I know why canards are "stall-proof", but I know I'd bungle the explanation trying to put it into layman's terms.

Johnny L.A.
10-14-2003, 09:00 PM
Personally, I thought "his head was ripped off" was plenty explicit enough
Erm... That would have been me. :o
someone else with a little better grasp of aerodynamic engineering might wish to explain why a bunch of us out here are saying things like "you can't stall a canard."
IANAAE, but here's how I understand it. If a canard aircraft is approaching an airspeed and attitude combination that would stall a conventional airplane, the canard stalls. This lowers the nose before the wings reach the critical airspeed/attitude configuration.

This doesn't mean that you can't stall a canard, but that a properly designed canard-configured aircraft should be more stall resistant than an aircraft with a conventional layout.

Johnny L.A.
10-14-2003, 09:08 PM
Incidentally, this is a Long EZ (http://long-ez.com/). The pods you see under the wings are not fuel tanks (as on fighter jets), but cargo pods. According to the NTSB report, Denver's aircraft was fitted with pods; but I'd have to re-read it to see if it says if they were attached during the last flight.

The reason you see no nosewheel is that it is retractable to reduce drag. The nosewheel is also retracted for parking, which keeps the aircraft from tipping backwards.

Extraneous
10-14-2003, 10:26 PM
Canards are stall resistant - if built correctly. The reason that Velocity now sells their kits with pre-formed wing cores is because a fellow managed to put his plane into a deep stall - twice. The second was fatal.

But yes, the canard (the little wing out front, just like the Wright flyer) is designed to stall (stop producing lift because it's angle of attack (pitch relative to the wind) is too great) before the wing, thereby causing the nose to drop, thus preventing the wing from getting its AOA high enough to stall.

Think of when you were a kid and stuck your hand out the car window, palm down - remember altering the pitch of your hand, and if you got it too high, the wind would whip it backwards? That is the kind of thing an aerodynamic stall is.

(not bad for someone who knows nothing about planes, huh?)

Sam Stone
10-14-2003, 10:41 PM
Broomstick:

The simple answer is that the canard is designed to have a lower critical angle of attack than the main wing. So the canard stalls before the main wing does, and the nose drops.

In a conventional aircraft, the center of lift of the wing is behind the center of gravity. Therefore, without a tail, the aircraft would want to pitch over on its nose. A conventional tail therefore creates negative lift - it is designed to push the back of the airplane down to keep the nose up. When set up right, this causes the airplane to be stable - if the plane slows down, the tail force decreases, the nose pitches down, and the airplane accelerates back to its trimmed speed. If the plane goes too fast, the tail pushes down more, and pulls the nose up.

The problem with a conventional tail is that it is creating a downforce acting against the lift of the wing, which makes the wing have to work harder to keep the airplane aloft. That causes an increase in induced drag, and makes the airplane a little less efficient.

A canard is fundamentally different, in that both the canard and the wing create positive lift. Think of the airplane as being supported on both ends by a column of air. Because both surfaces create lift, the canard is theoretically more efficient. And because both create lift in the same direction, and both have a positive AOA all the time, you can set them up so that the canard stalls first when the nose is raised. So the nose falls forward, the canard gains lift, the nose comes up, the canard stalls, etc. The main wing never stops flying. In a properly set up canard airplane, holding the stick back in your lap will result in the thing bobbing along like a sick duck, but still flying.

So why aren't all airplanes canards? There are a number of reasons - like anything in aviation, there are no perfect solutions. One of the problems with a canard design (maybe the biggest problem) is that they need lots of runway and land very fast. Again, because the canard stalls before the wing does, you have to fly the airplane onto the runway. In a conventional airplane, you can do a full-stall landing and use the maximum lift capability of the wing. No can do in a canard airplane.

Another problem is where to put the engine. Canards need nice smooth uninterrupted airflow, so you don't want to stick one behind a propeller. So most canard aircraft have their engine in the back, and that creates a number of design headaches - everything from cooling to propeller strikes to strange pitch behaviour when power is applied.

Finally, there are conditions under which you can stall a canard. Several canard aircraft have suffered from 'deep stall' problems. Basically, what happens is that the wing design that is usually dictated by a canard (swept back aft wing) can set up a situation where at an angle the Cg of the airplane actually moves behind the center of lift. So even though the canard stalls and stops flying, the nose won't come down.

There's an airplane called a 'Velocity' that had this problem. I remember reading an accident report where the pilot got into a deep stall, and tried everything he could to get out of it, including opening the door of the plane and trying to climb out into the nose to help it go down. Nothing worked, so he sat back down, and realized that he was only descending at a few hundred feet per minute (a deep stall in this airplane was a very high drag situation). So basically he just buckled up, braced himself, and waited for impact. The airplane went SPLAT in shallow water just offshore, and the pilot got out completely uninjured. And the airplane was towed in and flew again.

And I'm sure that's more than anyone in this thread wanted to know about canards!

Sam Stone
10-14-2003, 11:21 PM
Johnny: I prefer 'human factors' to 'pilot error' when there are mitigating circumstances like this, because it helps to get the idea across that pilot error isn't quite as cut-and-dried as it sounds.

For instance, if I designed an airplane with the gear lever right beside the flap handle, but wired so that the gear was 'down' when the lever was 'up', I can guarantee that that airplane would have far more than its fair share of accidental gear up landings. Sure, if a pilot carelessly reaches over and flips the gear switch instead of the flaps, it's 'pilot error'. But just saying that masks the fact that there is a real flaw in the design of the airplane.

In the case of John Denver's Long-EZE, the placement of the fuel selector was a usability nightmare. It ensured that the pilot put himself in a very difficult position to fly the airplane, at a time when he most needs to fly.

Now sure, one can be supremely careful with fuel management, practice constantly, and make that fuel selector as safe as anything else in the airplane. But the design gets in your way.

Human factors is an interest of mine, and also part of my job (usability of software). I highly recommend a book called The Design of Everyday Things (http://amazon.com/exec/obidos/tg/detail/-/0465067107/qid=1066187342/sr=8-1/ref=sr_8_1/002-9187935-1351250?v=glance&s=books&n=507846), which is a great introduction to this stuff.

For example, consider how many times you've pushed on a door that you were supposed to pull. Often, the door will just have a bar on each side which can be pulled or pushed. With such a door which doesn't give you natural cues as to its function, no amount of signs saying PUSH or PULL will stop people from pulling when they should push or pushing when they should pull. It's too hardwired in us. But put a pulling handle on one side, and a push plate on the other, and suddenly we all 'get it' and never made that mistake. Simple things.

Homebuilt aircraft are human factors disasters. It's usually the last thing an amateur builder considers, especially when he's making the airplane for himself. That complicated latch mechanism is intuitively obvious in function - to the guy who designed and painstakingly built it. To everyone else, it may be a nightmare, and when you need to get out of your airplane in a hurry, that strange latch mechanism will thwart you.

Airplanes are usually very good at human factors, because designers have studied it for years. Take a simple throttle control - push forward, go forward. Pull back, slow down. Imagine if the throttle was a dial that you turned right and left instead. You'd have to think about which way to turn it all the time. And imagine if half the airplanes you flew had counterclockwide = more power and the other half did the opposite. Sure, pulling the power by accident when you need to apply it is pilot error, but it's understandable.

In homebuilts, this happens all the time. And that's what killed John Denver. Sure, the proximate cause was that he screwed up. But there really was a much larger issue.

Bookkeeper
10-15-2003, 12:40 AM
Originally posted by Sam Stone
Airplanes are usually very good at human factors, because designers have studied it for years. Take a simple throttle control - push forward, go forward. Pull back, slow down. Imagine if the throttle was a dial that you turned right and left instead. You'd have to think about which way to turn it all the time. And imagine if half the airplanes you flew had counterclockwide = more power and the other half did the opposite.
This was actually a problem at one point during WW2, when the RAF took over a number of different American aircraft after the fall of France in 1940 from French Air Force contracts. The French used a throttle setup which worked in the opposite direction from the the British/American norm, and the A/C all had to be modified before RAF pilots could fly them safely.

Richard Pearse
10-15-2003, 02:38 AM
Originally posted by Bookkeeper
This was actually a problem at one point during WW2, when the RAF took over a number of different American aircraft after the fall of France in 1940 from French Air Force contracts. The French used a throttle setup which worked in the opposite direction from the the British/American norm, and the A/C all had to be modified before RAF pilots could fly them safely.

Here's a nice example of a SNAFU waiting to happen:

The North American T6 Texan was operated in various countries as the T6 Harvard. The Harvards that made their way to New Zealand (and other Commonwealth countries I imagine), had a fuel mixture control where fully aft was rich mixture, and forward was lean. Other Harvard/Texans had the standard mixture control, forward = rich, aft = lean. The problem is that putting the mixture to lean when you want rich will kill the engine. Of course in today's Warbird loving aviation society there's no guarantee that a Harvard you fly in NZ will have the mixture layout you're familiar with! Generally you figure it out when the aircraft engine won't start, but it could still be a problem in an emergency situation.

Or how about the Beech Baron which has the propellor and throttle controls reversed as well as the flap and gear levers. It's not a good look when you retract the gear instead of the flap on the ground.

Or the Spitfire which requires you to swap hands on the flying controls to retract the gear.

Unfortunately aircraft manufacturers don't put nearly enough thought into Human Factors as they should.

pilot141
10-15-2003, 03:20 AM
Human factors - I love this stuff. The John Denver crash is a perfect example of this. Something that looks fine and dandy while you are standing on the tarmac becomes a nightmare when airborne.

I'll share two personal human factors stories - one bad, one good.

The bad one is from an older airplane, the venerable 727. I sat sideways on that thing flying the panel for 18 months, and I can assure you that human factors never trickled down to the 727 FE panel. It was obvious that every system (fuel, hydraulics, electrics, pneumatics, etc) was designed by a different person. On one system (fuel) an illuminated light indicated that something was NOT working (ie a boost pump). On a different system (anti-ice) an illuminated light meant that the system WAS working. And for fuel crossfeed, the light FLASHED ONCE after you activated the switch. Before and after activation it was not illuminated. Multi-position switches also were not consistent. For fuel, a normal flow had all knobs vertical. For electrics, a normal flow had all knobs horizontal. In addition, every system used one of three colors of lights in a different way - an illuminated blue light was good for anti-ice, but bad for fuel. Overall, a human factors nightmare. The only way to overcome it was repitition, repitition and more repitition in the simulator. And even after that guys still screwed things up. If you promise not to sue, I'll tell you the story of one poor soul:

Fresh out of training and flying the line, he forgot to turn on ANY fuel boost pumps on taxi-out. Not a problem while taxiing and while flying at lower altitudes, because the engines can suction-feed the fuel. As the 727 climbed, he never noticed that the boost pumps were off. Passing 30,000 feet everyone figured it out as all three engines flamed out due to fuel starvation! :eek:

Now for the good. On newer airplanes, and even older ones that we acquire from other airlines, some human factors lessons are applied. For example, on the MD-80s every switch on the overhead panel has it's "ON" position as forward. In this case "forward" means the same direction you push the throttles to accelerate. So no matter what system you are reaching for, to turn it on you move the switch forward. To turn it off, move it backward. Same thing on the forward console panels - up is on, down is off. Always. Some airplanes came to us with different switchology, but they were modified to our standard before they came on the line. Consistency like this is a VERY good thing, because you do not have to think about which way to throw any switch to get the desired effect.

Human factors design in airplanes is a constantly evolving process. Airplanes made today have learned many lessons from the past - gear handles are shaped like a small wheel, flap handles look like a flap, etc. But the new problems are occuring where advances are being made - namely automation. The phrase "why is it doing that?" has been uttered countless times in simulators and aircraft across the globe. Different philosophies about automation (the most notable being between Airbus and Boeing) result in vastly different methods for accomplishing the same task. The current strive for common automation practices is similar to past battles fought for common mechanical practices. Lessons will be learned (often in blood), and a standard will eventually appear.

Of course these standards would never be required for a homebuilt like the Long-EZ, but you always hope that people are learning SOMETHING from other people's mistakes.

Broomstick
10-15-2003, 05:43 AM
Talking to a Southwest pilot I know, it is my understanding that, not only does Southwest fly only 737's, but when they buy another one they do whatever is required to make the cockpit of the new 737 conform the the layout of all their other 737's. Which means no matter which of this guy's employer's airplanes he sits down in, he knows exactly where everything is and how it works. And the reason is... human factors.

(Also, cheaper to only have to train people to work on just one type of airplane, keep parts for only one type of airplane, etc.)

If the NTSB started a "human factors" category distinct from "pilot error", I wonder how many accidents now labeled "pilot error" would fall partly or wholly into the new category?

Sublight
10-15-2003, 08:24 AM
pilot141, as a complete non-pilot, I have a question about your "bad" example: is it possible to re-start the engines in that situation, or did you learn about what happened from the flight recorder?

Johnny L.A.
10-15-2003, 08:47 AM
Sam Stone: I agree with you. I didn't mean to imply that it was solely pilot error, and not a human factors error. The placement of the fuel selector was extremely poor. As we all know, crashes are usually not caused by a single mishap, but by a string of events.

The aircraft in question was powered by a Lycoming O-320-E3D, which has a higher rate of fuel consumption than the Lycoming O-235 or Continental O-200 for which the aircraft was designed. Still, Denver flew several types of aircraft and would have been familiar with the fuel consumption on this type of engine.

Denver knew that he would be unable to easily reach the fuel selector handle, even with the addition of a pair of vice-grips.

In my opinion, Denver made a serious error when he failed to get fuel. Had he refueled before taking the aircraft up, (according to the NTSB) "the pilot's [attention would not have been diverted] from the operation of the airplane and his inadvertent application of right rudder that resulted in the loss of airplane control while attempting to manipulate the fuel selector handle."

Since Denver knew the burn rate on the engine, and he knew approximately how much fuel was remaining, and he knew that he could not easily manipulate the fuel selector, I think his decision not to refuel was "pilot error".

But you are absolutely correct that the placement of the fuel selector is a human factors issue.

Algernon
10-15-2003, 08:57 AM
Originally posted by Sam Stone
And I'm sure that's more than anyone in this thread wanted to know about canards! Not at all. I know this is frowned upon, but I'm going to do a driveby (flyby?) post. I think that sometimes congratulating a job well done is more important than resting the hamsters.

Great work Sam Stone and Broomstick. Thorough and informative posts. I, for one, greatly appreciate the effort you took to write them.

pilot141
10-15-2003, 10:03 AM
Originally posted by Sublight
I have a question about your "bad" example: is it possible to re-start the engines in that situation, or did you learn about what happened from the flight recorder?

The engines are easily restarted once you turn the boost pumps on. They lost some altitude, got the engines restarted and continued to their destination. We learned about it from a company-wide message that said "DON'T do what these guys did!"

handy
10-15-2003, 11:03 AM
Broomstick, sorry about that, next time Ill try that nifty spoiler box thing. I hope I don't find some of those extra parts laying around when I'm surfing. I have surfed that spot since the plane incident, however. That link also has some interesting info on the plane, but not much more than has already been written here.

St. Urho
10-15-2003, 01:58 PM
Originally posted by handy
I have to agree with Broomstick that he flew into the water at a high rate of speed, but was there water in his lungs? Wouldn't the fact he was under water be a factor?

There wouldn't necessarily have to be water in his lungs even if he did drown. (https://academicpursuits.us/classics/a1_211.html)

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