Mailing List lml@lancaironline.net Message #53470
From: Ron Laughlin <ronlaughlin@gmail.com>
Sender: <marv@lancaironline.net>
Subject: Re: [LML] What could be causing this in-flight noise on my Legacy?
Date: Tue, 17 Nov 2009 18:53:23 -0500
To: <lml>
Engine backfiring?
Ron



On Tue, Nov 17, 2009 at 9:43 AM, Jay M. Sabot
<jsabot@oxforditconsult.com> wrote:
Yesterday afternoon while flying Legacy N26XY (with about 17 hours to date),
power and speed were reduced to explore the lower speed range of the
airplane. Was at 4,500 MSL, smooth air.



As the airplane decelerated thru 89 knots TAS, once or twice a sound was
heard that can best be described as a door closing shut firmly. It sounded
like a landing gear door being slapped against the fuselage/cowling by the
slip stream. However, the gear was retracted.



Opening the throttle and increasing speed eliminated the noise. The slapping
sound, like a door closing firmly, did not reoccur. The noise occurred only
once or twice per event. I proceeded to repeat the flight conditions, and
the same thing happened: As the airplane decelerated to below 90 knots with
the gear retracted and no flaps extended, just like the first time, the
noise was heard again two or three times over about 6 or 7 seconds. The
throttle was advanced and the noise did not repeat itself.



I reduced the throttle and lowered the landing gear and allowed the airplane
to decelerate again. Same thing happened with the gear extended, (no flaps).
A sound much like I imagine would be made if a gear door was swinging loose
in the slipstream and occasionally hitting the wing skin or cowling.
Advancing the throttle and retracting the gear was normal and the noise did
not reoccur.

Returned for a normal landing.

In the hangar, the gear and doors were examined only to find them all
attached firmly as they have been from the beginning. Nothing is loose, no
sign of anything striking the cowl or lower wing skins.

Anyone had any similar experience?  Would appreciate any commentary on the
situation and their findings in this regard.





Thanks all.



Jay M. Sabot




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