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Thread: 2-Blade Propeller Hub Inspections
Message: 2-Blade Propeller Hub Inspections
Follow-Up To: ACRO Email list (for List Members only)
From: Skrud at aol.com
Date: Thu, 04 Jan 1996 13:39:56 UTC
>From the previous request about information concerning propeller hub
inspections:
Hartzell Propeller Service Bulletin 164C dated September 11, 1992 briefly
states:
Subject: Inspection for Cracks in Certain Two Blade "Y" Shank Aluminum Hubs
Effectivity: HC-C2YK -( )( )( ) or HC-C2YR-( )( )( ) type propeller hubs
installed on:
- aerobatic aircraft regardless of engine model or propeller serial
number
- all other aircraft with Lycoming (T,I)O-540 series engine rated at 260
HP and 2700 RPM or higher and propeller serial number range CH19835
through CH26050
"There have been incidents of hub cracks in Hartzell two blade "compact"
aluminum hub propellers. In nearly every case, blade separation did not
occur due to timely inspection (sometimes associated with reports of
abnormal vibration or grease leakage). Cracks typically initiate at the same
point on the hub. The cracks are external and are observable with careful
examination. the cracks originate at a point adjacent to the blade called
the "fillet radius". As cracks propagate toward the center of the hub, their
progression accelerates and results in failure of one hub half which can
then, potentially, progress to blade separation.
WARNING: UNEXPLAINED VIBRATION OR GREASE LEAKAGE INCIDENTS, WHERE THE
CONDITION INITIATED SUDDENLY, DEMAND IMMEDIATE INSPECTION FOR POSSIBLE
CRACKED HUB."
Compliance:
Hartzell has developed a new hub which has a different contour in the fillet
radius and different shot peening. These hubs are exempt from repetitive
inspections. These hubs are identified by the suffix letter "A" at the end
of the hub serial number and propeller serial numbers.
Inspection is required within the next 25 hours of operation [ ], and
thereafter at intervals not to exceed 50 hours, or 50 flights whichever
occurs first, of operation from the last inspection.
The procedure for inspection, line drawings of the affected area, and
additional information are included in the SB.
Anyone wishing a mailed or faxed copy of the SB can contact me with the
appropriate information, I'll be happy to get it right out to you...
Scott H. Rodriguez, IAC# 18601
Test Engineer
Hartzell Propeller Inc.
One Propeller Place
Piqua, OH 45356
Skrud at aol.com
513-778-4370 (voice)
513-7784365 (fax)