Today's Message Index:
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1. 04:33 PM - Re: F-35 accident (Ron Davis)
2. 05:36 PM - Re: F-35 accident (BobsV35B@aol.com)
3. 09:43 PM - Re: F-35 accident (Gary Strong)
Message 1
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| Subject: | Re: F-35 accident |
--> Beech-List message posted by: Ron Davis <radavis2522@netzero.net>
Robin,
In-flight breakups are always scary. Occupants don't survive, and the
public *always* attributes the cause to the vee tail, regardless of what
actually happened.
Too soon to tell, but a believable scenario is this:
Pilot reports airport in sight (Middlesboro, KY, 1A6). He is 8 miles away
and at 5,500 ft. At 160 mph, that's about 5 minutes away. Elevation is
1154 ft, so the traffic pattern is probably 1254 ft.
The pilot begins descending, but ends up at 4,400 ft. only 2 miles away from
the airport, or about 3,000 ft. too high.
It is quite possible that the pilot (with the throttle still firewalled)
simply pointed the nose downward to lose the remaining altitude. The
Bonanza will pick up a LOT of speed that way and you're past redline before
you know it. Whoops! Yank back on that wheel so slow her down again, and
... you've just traded in your wings for your own personal set of wings and
bonus harp. It's been nice knowing you.
When I need to dump a bunch of altitude, I use a forward slip. My plane
(1954 E35) will drop like a stone without picking up deadly speed. 2,000
fpm is possible (but tiring) without exceeding 165 kts. But I don't think
I'd ever try to lose 3,000 ft in two miles.
Ron Davis
Newport Beach, CA
ROBINFLY@aol.com wrote:
> --> Beech-List message posted by: ROBINFLY@aol.com
>
> I found this F-35 "in-flight break-up" accident in VFR condition. What might
> be the cause? I have an "E" and causes of early Bo break-up always
> interested me for obvious reason. Robin Hou, San Marino, CA.
> <A HREF="http://www.ntsb.gov/ntsb/brief.asp?ev_id=20030805X01268&key=1">NYC03FA148 This is the link to NTSB's preliminary information.
Message 2
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| Subject: | Re: F-35 accident |
--> Beech-List message posted by: BobsV35B@aol.com
In a message dated 8/12/03 6:34:26 PM Central Daylight Time,
radavis2522@netzero.net writes:
> Too soon to tell, but a believable scenario is this:
>
> Pilot reports airport in sight (Middlesboro, KY, 1A6). He is 8 miles away
> and at 5,500 ft. At 160 mph, that's about 5 minutes away. Elevation is
> 1154 ft, so the traffic pattern is probably 1254 ft
>
How about maybe 2154?
Good Evening Ron,
Nice to hear from you. It's been a while.
I am afraid I will have to disagree somewhat with your scenario. The weakest
Bonanzas ever built were the very early straight 35s.
Back when they started shedding wings, Beech borrowed an autopilot from the
Navy which was designed to fly a drone. They installed it in one of the early
airframes. I think it was D-5, but I am not sure of the exact number.
The Bonanza was flown by a pilot sitting in a Twin Beech using the drone
controls. They made a series of ever increasing high "G" pullouts. After each
test the airframe was inspected. Even at maximum gross weight, the airplane
easily withstood 4.4 Gs, the load required for Utility category. At the max
gross that airplane was designed for, and certificated in, the Normal category
only required that it be able to withstand a G loading of 3.8.
The tests were continued until such time as the structure showed some
evidence of deformation or permanent set in the structure. That occurred at 5.5
Gs.
The A35 was beefed up considerably and it was certificated in the normal
category at full gross weight. As the airplanes continued to shed wings, Beech
kept making them stronger and stronger.
They envisioned a scenario such as that you described.
Rumor has it that by the time the H35 was built, the wings could easily
withstand a full eight Gs.
Trouble was, it wasn't the high speed pull out that was peeling off the
wings.
The most likely scenario is that the pilot got into a high G situation and
then, either let go of the stick or, possibly, even pushed it forward to unload
the wing. When that happens, the tail is overloaded. It comes off, the
airplane tumbles end over end and even the eight G wing will break.
While I certainly agree that the airplane should always be flown inside the
envelope for which it was designed, I don't think anyone has ever pulled a wing
off a conforming Bonanza, or any of it's derivatives, by just pulling back on
the stick. It is much more likely that the airplane has been tumbled when
some poor aviator suddenly realized he was pulling a lot of Gs and he/she tried
to unload it too quickly.
My vote for a good way to lose altitude fast would be to slow down, drop the
gear and let her drop.
However, there is nothing wrong with using the slip!
Happy Skies,
Old Bob
Message 3
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--> Beech-List message posted by: "Gary Strong" <gstrong@att.net>
While we assume everyone has complied the various ADs and keep their
ruddervators balanced and well maintained (absolutely no slop in the
bearings), we know that isn't always the case. The buckling of the skin
makes me wonder if we've now experienced another ruddervator problem.
In reading last month's ABS magazine, I think we're up to 3 ruddervator
accidents with what appears to be balaced ruddervators prior to the
accident.
At Oshkosh, I asked the ABS tech person if there were any reports of
ruddervator problems on 1970s V35Bs. He said he wasn't aware of any and
that the design had changed significantly in terms of control pressure,
pushrod design, etc. I then asked about the 1960s and he replied that
it appears virtually all of the aircraft that have had the problem have
been 1950s or before. My main reason for asking the questions was #1 -
to see if he know what had happened to the 3 aircraft that are still
being investigated, and #2 - to find out if I should be concerned at all
about my 1979 V35B. Lastly, when I needed to get my ruddervators
re-skinned last winter I asked a couple of control rebuild shops a
similar question, and they also replied the 1950s versions are more
susceptable. In all this however, it was emphasized with appropriate
maintenance the aircraft is not to be worried about.
How does this explanation sound to everyone on the list? Have the later
V35Bs not had problems? Are they that much different in design? Any
more knowledge on the 3 the ABS magazine mentioned?
Thanks!
Gary S.
1979 V35B
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