Osprey vs. Harrier

John Halliwell wrote:

:In article , Fred J. McCall
writes
: Now, the mechanical rate shouldn't come
:as a surprise to anyone with two neurons to rub together, given that
:the AV-8 is older technology, more mechanically complex to begin with,
:and only has a single engine so any engine failure pretty much toasts
:you.
:
:VSTOL JSF has only one engine and is even more mechanically complex.

Yeah. I know. The claim is that reliability has improved so much
over the past decades that it is now perfectly reasonable to adopt
Naval aircraft with single engines.

Needless to say, I'm not convinced. I'm even less convinced about
that whole lift-fan drive train for the -C version. It may make
transitions and hover easier - but only up until the first non-perfect
moment of the hardware has. It strikes me as a smoking hole waiting
to happen.

But then, I don't design airplanes and I'll never have to fly in the
thing....

--
"Millions for defense, but not one cent for tribute."
-- Charles Pinckney

Peter H. Granzeau wrote:

:On Sat, 09 Aug 2003 08:11:18 GMT, Fred J. McCall
wrote:
:
:So the game is to just keep changing the statement when the preceding
:one proves up wrong?
:
:Yeah, that shows a lot of intellectual integrity....
:
:Why was it necessary to take a discussion of facts and turn it into a
:discussion of rhetoric?

Because the other side was being fact free....

In article , Fred J. McCall
writes
Yeah. I know. The claim is that reliability has improved so much
over the past decades that it is now perfectly reasonable to adopt
Naval aircraft with single engines.

The single engine obviously makes the loss of the aircraft more likely,
especially in naval ops where you're basically limited to vertical
landing. The real problem is engine failure in the hover, where the
pilot has very little time to react and has no option to save the
aircraft (makes his decision a bit easier, his only option is to pull
the handle).

The attitude with the Harrier seems to be, if the engine stops, your
trained military pilot pulls the handle and wins a Martin Baker tie.

With multi-engined VSTOL, losing an engine in the hover usually has the
same result, except the aircraft may not fall in a stable fashion,
making escape harder. If you cross-connect two engines like the V-22,
you always need twice the power you actually need. With a tilt-rotor,
the last place you want big engines is on the end of the wings,
especially if you're trying to tilt the whole mass of the engine. Better
to put the engines in the middle and take the drive to the props.

VSTOL JSF has the worst of both worlds, a single engine and two lift
mechanisms.

--
John

Fred J. McCall wrote:
Iain Rae wrote:

snip

: So the game is to just keep changing the statement when the preceding
: one proves up wrong?
:well, the statement was
:"It's a training problem - marines don't have to take perisher."
:
:you're the one who limited it to pilots.

Your maintenance grunts go through that?

No, neither do our pilots, it's a submarine commanders course. FFS go
out and try to buy yourself a sense of humour and then read the
submersible harrier threads.



: Yeah, that shows a lot of intellectual integrity....
:
:Well, if that's how you want to tar yourself go ahead.

Somehow, I knew you'd try this sort of trolling misdirection from your
own behaviour. Either address the real issue or shut up.

AV-8 has 4 times the major accident rate of the other fixed wing
aircraft the Marines fly (the F/A-18) in US service. The human error
rate is over twice as large, and the catastrophic mechanical failure
rate is EIGHT times as large. Now, the mechanical rate shouldn't come
as a surprise to anyone with two neurons to rub together, given that
the AV-8 is older technology, more mechanically complex to begin with,
and only has a single engine so any engine failure pretty much toasts
you. The human error rate also shouldn't come as a huge surprise to
anyone with two neurons to slap wetly together, since vertical landing
is obviously difficult.

Then comes you. So, tell me - just how is the statement that the AV-8
is the most dangerous aircraft currently in US service incorrect (or
even surprising) given the preceding?

It's not. I never claimed otherwise, clearly though from the article
human error also applies to the ground crew, not just the pilots. And
the article seems to imply that this is above the norm. To add to your
list of reasons above I'd imagine that an aircraft which is being
maintained out of rough forward bases is going to have a higher level of
ground crew ****ups than one which is based on a carrier or at a base.




So, what's the accident rate (under the same criteria used in the US)
for the Harrier in British service? No fair comparing apples and
aardvarks; you have to use the same criteria.



The only info I have is for all RAF harrier types (GR7 and T10) from
1988 to 2001 which lists the damage rate per 10,000 hours at 1.17.

The figures are for "damaged beyond local repair" or "loss of aircraft",
there's no monetary value attached .

For comparison the Jaguar is listed at 1.13 and the GR1/GR4 is listed
at 0.65.

Strangely there's an entry of 0.31 from 1989 for Lysander (I have to
assume this is a typo for something else).

In article , vince
writes
The truth, for both aircraft and the V 22 is somewher between these
extremes.
The Boeing 777 for example is rated to fly for three hours and about
1300 miles on one engine.

That's more to do with the reliability of the chosen engine, after one
fails the chances of the other failing is statistically small to make it
improbable (as far as the regulations are concerned). The reliability
required when ERTOPS started (Extended Range Twin Engined Operations)
was something like less than one engine shutdown (on the engine type)
per 100,000 flight hours (that was when it was 120 minutes instead of
180).

All twins should fly on one engine after a fashion, for conventional
flight this is not too big a problem. The trade off is smaller because
you can trade climb performance, altitude and airspeed (to an extent)
for the extra power needed, so you don't need twice the power needed for
take-off to fly.

The V-22 IIRC is supposed to be able to land vertically on one engine,
and take off empty in an emergency on one engine. I'm not sure this
has been demonstrated yet.

The scenario I'm thinking of is a heavily laden V-22 leaving a carrier
with an engine failure occurring during transition. With very little
height or forward speed to play with (and the possible need to return to
the carrier for safe [vertical?] landing), it needs enough power to
maintain height on a single engine (by definition equal to its weight).

This scenario is significant because this is where many Harrier losses
occur (a problem that will always exist with fixed wing VSTOL aircraft
due to the envelope they operate in when hovering). There is no other
way to save the aircraft other than brute force vertical thrust.

The only way round it may be to take-off with a low fuel load and refuel
immediately, but that takes away some of the efficiency advantages the
V-22 claims.

--
John

In article , Fred J. McCall
writes
Either you folks are operating some fairly dangerous aircraft or else
you have a training problem. Scaled back to 10,000 operational hour
rates and assuming Class A equates with 'loss of aircraft' (which
isn't quite true - rates would be lower under 'loss of aircraft'
criteria), various US types in our service would have the rates below:

AV-8B - 1.2
F/A-18 - 0.3
F-16 - 0.35
F-15 - 0.5

Just out of interest how would the stats look if you went from
operational hours to launch/recovery cycles?

Given that the Harriers usually have much shorter sorties time wise
(from memory averaging less than an hour in GWI?) and the others often
fly much longer sorties with multiple refuellings. Since most accidents
happen during launch/recovery, the longer the sortie, the lower your
accident rate becomes statistically per operational hour.

--
John

"Fred J. McCall" wrote:

Iain Rae wrote:

:Fred J. McCall wrote:
: Iain Rae wrote:
:
:snip
:
: : So the game is to just keep changing the statement when the preceding
: : one proves up wrong?
: :well, the statement was
: :"It's a training problem - marines don't have to take perisher."
: :
: :you're the one who limited it to pilots.
:
: Your maintenance grunts go through that?
:
:No, neither do our pilots, it's a submarine commanders course. FFS go
ut and try to buy yourself a sense of humour and then read the
:submersible harrier threads.

Go read them yourself. You'll find my name. I just don't
automatically remember nicknames for YOUR training.

: : Yeah, that shows a lot of intellectual integrity....
: :
: :Well, if that's how you want to tar yourself go ahead.
:
: Somehow, I knew you'd try this sort of trolling misdirection from your
: own behaviour. Either address the real issue or shut up.
:
: AV-8 has 4 times the major accident rate of the other fixed wing
: aircraft the Marines fly (the F/A-18) in US service. The human error
: rate is over twice as large, and the catastrophic mechanical failure
: rate is EIGHT times as large. Now, the mechanical rate shouldn't come
: as a surprise to anyone with two neurons to rub together, given that
: the AV-8 is older technology, more mechanically complex to begin with,
: and only has a single engine so any engine failure pretty much toasts
: you. The human error rate also shouldn't come as a huge surprise to
: anyone with two neurons to slap wetly together, since vertical landing
: is obviously difficult.
:
: Then comes you. So, tell me - just how is the statement that the AV-8
: is the most dangerous aircraft currently in US service incorrect (or
: even surprising) given the preceding?
:
:It's not. I never claimed otherwise, clearly though from the article
:human error also applies to the ground crew, not just the pilots. And
:the article seems to imply that this is above the norm. To add to your
:list of reasons above I'd imagine that an aircraft which is being
:maintained out of rough forward bases is going to have a higher level of
:ground crew ****ups than one which is based on a carrier or at a base.

Except, despite the ability, most AV-8s in US service aren't "being
maintained out of rough forward bases" most of the time.

: So, what's the accident rate (under the same criteria used in the US)
: for the Harrier in British service? No fair comparing apples and
: aardvarks; you have to use the same criteria.
:
:The only info I have is for all RAF harrier types (GR7 and T10) from
:1988 to 2001 which lists the damage rate per 10,000 hours at 1.17.

Ok. First scale it to 100,000 hours, which is how we measure them.
That gets you to 11.7, which is not appreciably different than the
12/100,000 hours that we're seeing on the Harrier.

:The figures are for "damaged beyond local repair" or "loss of aircraft",
:there's no monetary value attached .

Now add in those accidents which caused sufficient damage to qualify
as Class A but did not involve the loss of the aircraft (the value of
which is well over the limits of Class A). It looks to me like the
Class A accident rate for the Harrier in British service is *HIGHER*
than that for the aircraft in US service.

Still not quite the same thing, since the numbers largely represent
different Marks of Harrier, but indicative that in general this
aircraft has a much higher major accident rate than is usual.

:For comparison the Jaguar is listed at 1.13 and the GR1/GR4 is listed
:at 0.65.

Either you folks are operating some fairly dangerous aircraft or else
you have a training problem.

The Brit attack a/c spend a lot more time at low level than we do.

Scaled back to 10,000 operational hour
rates and assuming Class A equates with 'loss of aircraft' (which
isn't quite true - rates would be lower under 'loss of aircraft'
criteria), various US types in our service would have the rates below:

AV-8B - 1.2
F/A-18 - 0.3
F-16 - 0.35
F-15 - 0.5

If you want to go by European loss rate per 10,000 hours, for
'fighters' (various aircraft types, of course) the data for 2000 looks
like:

USAFE - 0.54 (all F-15s)
Britain - 0.15
Czech - 8.0
France - 0.29
Greece - 1.0
Italy - 0.5
Poland - 0.75
Romania - 1.5
Spain - 0.48
Turkey - 0.71

Everyone else had 0 (and the Germans and Israelis didn't report number
of hours flown, so nobody knows what their rates are). It's of note
that Britain, France, Greece, Italy, Spain, and Turkey are reporting
an order of magnitude more flying hours than the others, so a single
crash for the US in Europe would jump the rate a lot more - if you're
under 100,000 flight hours, the statistics may not even out for any
given year.

Do the above rates include the navies of those countries? If so, both Italy and
Spain operate the AV-8B+.

Guy

Fred J. McCall wrote:
Iain Rae wrote:

:Fred J. McCall wrote:
: Iain Rae wrote:
:
:snip
:
: : So the game is to just keep changing the statement when the preceding
: : one proves up wrong?
: :well, the statement was
: :"It's a training problem - marines don't have to take perisher."
: :
: :you're the one who limited it to pilots.
:
: Your maintenance grunts go through that?
:
:No, neither do our pilots, it's a submarine commanders course. FFS go
ut and try to buy yourself a sense of humour and then read the
:submersible harrier threads.

Go read them yourself. You'll find my name. I just don't
automatically remember nicknames for YOUR training.

: : Yeah, that shows a lot of intellectual integrity....
: :
: :Well, if that's how you want to tar yourself go ahead.
:
: Somehow, I knew you'd try this sort of trolling misdirection from your
: own behaviour. Either address the real issue or shut up.
:
: AV-8 has 4 times the major accident rate of the other fixed wing
: aircraft the Marines fly (the F/A-18) in US service. The human error
: rate is over twice as large, and the catastrophic mechanical failure
: rate is EIGHT times as large. Now, the mechanical rate shouldn't come
: as a surprise to anyone with two neurons to rub together, given that
: the AV-8 is older technology, more mechanically complex to begin with,
: and only has a single engine so any engine failure pretty much toasts
: you. The human error rate also shouldn't come as a huge surprise to
: anyone with two neurons to slap wetly together, since vertical landing
: is obviously difficult.
:
: Then comes you. So, tell me - just how is the statement that the AV-8
: is the most dangerous aircraft currently in US service incorrect (or
: even surprising) given the preceding?
:
:It's not. I never claimed otherwise, clearly though from the article
:human error also applies to the ground crew, not just the pilots. And
:the article seems to imply that this is above the norm. To add to your
:list of reasons above I'd imagine that an aircraft which is being
:maintained out of rough forward bases is going to have a higher level of
:ground crew ****ups than one which is based on a carrier or at a base.

Except, despite the ability, most AV-8s in US service aren't "being
maintained out of rough forward bases" most of the time.

: So, what's the accident rate (under the same criteria used in the US)
: for the Harrier in British service? No fair comparing apples and
: aardvarks; you have to use the same criteria.
:
:The only info I have is for all RAF harrier types (GR7 and T10) from
:1988 to 2001 which lists the damage rate per 10,000 hours at 1.17.

Ok. First scale it to 100,000 hours, which is how we measure them.
That gets you to 11.7, which is not appreciably different than the
12/100,000 hours that we're seeing on the Harrier.

:The figures are for "damaged beyond local repair" or "loss of aircraft",
:there's no monetary value attached .

Now add in those accidents which caused sufficient damage to qualify
as Class A but did not involve the loss of the aircraft (the value of
which is well over the limits of Class A). It looks to me like the
Class A accident rate for the Harrier in British service is *HIGHER*
than that for the aircraft in US service.

I think the figures I gave will include your "class A", I'd imagine
anything that's going to cost $1,000,000 plus is outwith normal squadron
maintenance. Ok some might not but you're probably going to get repairs
that are below that which are handled off site. It seem a reasonable bet
to me that they're going to balance out.

Guy Alcala wrote:
"Fred J. McCall" wrote:

snip
:For comparison the Jaguar is listed at 1.13 and the GR1/GR4 is listed
:at 0.65.

Either you folks are operating some fairly dangerous aircraft or else
you have a training problem.


The Brit attack a/c spend a lot more time at low level than we do.


The figures for the F2 and F3 tornado (the interceptor version) are
0.2 so I guess most of the difference is going to be related to the low
level flying that goes with the GR4's

"Thomas Schoene" wrote:

:"Fred J. McCall" wrote in message

:
: Yeah. I know. The claim is that reliability has improved so much
: over the past decades that it is now perfectly reasonable to adopt
: Naval aircraft with single engines.
:
:YM, readopt single-engine aircrfat. The Navy used to have no major problem
:with single-engine fighter/attack aircraft. Counting only jets, the service
:has had about as many single engine types as twins. And some of those were
:regarded as great aircraft (the A-4 for example)

We used to accept as routine much higher accident rates than we do
now. The F-8, for example (an incredible airplane for its day), had a
Class A accident rate of 14/100,000 hours and was regarded as a great
airplane. Note the criticism the AV-8 is taking with an accident rate
significantly lower than this.

: Needless to say, I'm not convinced. I'm even less convinced about
: that whole lift-fan drive train for the -C version.
:
:Just to avoid confusion, the STOVL version is the F-35B

Yeah. Brainfarts happen. :-)

: It may make
: transitions and hover easier - but only up until the first non-perfect
: moment of the hardware has. It strikes me as a smoking hole waiting
: to happen.
:
:True of any direct lift aircraft doing a VL, really. The Boeing design
:depended on having two long diverter ducts with various valves and gates
:working right. The McDD proposal depended on a second whole engine, which
:would have had to start reliably every time after cold soaking at
perational altitudes for a few hours. It's simply that VL is inherently a
:difficult regime to work in.

I still think the Boeing approach made the most sense, based on what
we know about this stuff. But man, that was an ugly airplane!

--
"Millions for defense, but not one cent for tribute."
-- Charles Pinckney