Propeller failure, prop failure, propeller fatigue, Light Sport
Aircraft News blog.
|
|
|
|
 |
|
|
|
|
|
Click here for this months specials! |
|
|
 |
|
|
Click
HERE to
receive Light Sport Aircraft News EXTRA!
Our monthly newsletter
packed full of information about ultralight aviation!
|
|
Propeller Fatigue . . . A time-bomb waiting to explode!
It is part of every pre-flight inspection, but how many times do we
take a magnifying glass to a propeller to check for cracks? Okay,
so that may be a bit of over-kill, but tiny cracks in the propeller
surface can occur.
When they do, beware!
Tragically, a Piper PA-28-140 pilot and his passenger learned this
lesson the hard way. The pilot, who had 160 hours total time, paid
with his life!
Within moments after liftoff from the Toughkenemon, Pennsylvania
airport, there was a loud metallic-sounding explosion. Oil sprayed
all over the windscreen.
|
|
|
The passenger later said, "It sounded like someone
threw a big chunk of metal in the engine, and the engine cowling opened
up like a can of sardines."
Again, according to the passenger, the pilot
maneuvered the airplane toward an open area bordered by trees. He noted
that they were too low to clear the trees. It then burst into flames
just as they hit the ground. The passenger escaped the wreckage, but
burned his hands in his efforts to assist the pilot.
The airplane was examined at the site and with the
exception of a propeller blade, all major components were accounted for
at the scene. A nearby resident later recovered the broken segment of
propeller.
The engine
 was
examined at the Lycoming Engine factory. Examination revealed no
pre-impact anomalies or mechanical deficiencies.
The cause!
According to the NTSB Report, the airplane was
manufactured in 1972, and had accrued approximately 4,813 total aircraft
hours. The airplane's engine had accrued a total of about 4,700 hours
of operation and about 475 hours since overhaul.
Examination of the airplane's maintenance records revealed that on April
6, 1995, an entry stated, "Remove paint, remove damage from face of
blades, correct angles, dress, track, balance, alodine, and repaint."
A subsequent entry dated May 7, 1998 stated that the propeller was "repitched
to 60" following an engine overhaul and conversion. Entries dated
July 6, 2001 and July 25, 2002, reflected annual inspections
respectively, each included "filed and inspected prop" in the
text.
Again, according to the NTSB
Report, the propeller and the associated broken segment were examined at
the Safety Board Materials Laboratory. Examination revealed that a large
portion of the fracture surface displayed crack arrest positions typical
of fatigue cracking. The fracture features emanated from an origin area
on the camber (forward) surface of the propeller.
NTSB Report click here!
Microscopic examination revealed an area of corrosion around the fatigue
origin, as well as sanding scratches and conversion (Alodine) coating.
The lesson . .
.
While rare as far as
accident causes, a propeller failure in flight produces devastating
consequences. The immediate imbalance caused by the separation of even
a small segment of the propeller can produce catastrophic engine
failure.
The best defense is a
careful examination of the propeller(s) prior to beginning any flight.
Look for chips, tiny cracks, and even scratches in the propeller surface
from tip to hub. If there is any question , don't launch without having
it looked at by a trained professional.
The above courtesy of
http://overtheairwaves.com/
|
|
|
|
1
2 3 4
5 6 7
8 9 10
11 12
13 14
15 16 17 18
19 20 Index for this section. |
|
|
|
|
|
|
 |
For hours and hours
of web video interviews on the world of Light Sport Aircraft subscribe to
the Ultralight Flyer web video magazine - Only $24.50 CDN (approximately
$19.50 U.S.) per year gives your access to web video on Light Sport
aircraft, aircraft builders, Light Sport Aircraft manufacturers,
designer, accessories and much, much more!
|
|
|
|
|
Light Sport Aircraft News Web Magazine PO Box 1710 Holland Landing
Ontario Canada L9N 1P2 647-723-8767.
You may link to these pages or print
them out for your own personal use.
No part of this
publication may be copied or distributed, transmitted, transcribed,
stored in a retrieval system, or translated into any human or computer
language, in any form or by any means, electronic, mechanical,
manual, or otherwise, without the written permission of Dave
Loveman.
By copying or paraphrasing the intellectual
property on this site, you're automatically signing a binding contract
and agreeing to be billed $10,000 payable immediately. Copyright Light Sport Aircraft News - Ultralight Flyer. Email
|
|
|
|
