AD/Phof/2 Amdt 3 Propeller Hub (Cth)

AIRWORTHINESS DIRECTIVE

On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/PHOF/2 Amdt 2 and issues the following AD under subregulation 39.001(1) of CASR 1998.  The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

Propellers - Variable Pitch - Hoffman

AD/PHOF/2 Amdt 3 Propeller Hub 7/2005

Applicability:

Hoffmann Propeller Model HO-V343K.

Requirement:

Using information contained in the applicable Operations and Maintenance Manual, Service Bulletin 61-10-03 SB E 15B dated 13 July 2004 or later LBA / EASA approved revisions and Service Instruction 61-10-05 SI E 4D dated 16 March 2005 or later LBA / EASA approved revisions:

1.    Carry out an examination of the propeller blade shake.

2.    Carry out an examination of the blade retention nut preload torque.

3.    Carry out an Ultrasonic Inspection of the propeller hub.

4.    Carry out an Eddy Current Inspection of the propeller hub, if the ultrasonic inspection shows any signs of damage.

5.    Exchange or repair the propeller if any blade shake or signs of cracks or damage of the propeller hub outside serviceable limits have been detected during the inspection.

Note:  German LBA Airworthiness Directive (AD) D-2004-352R4 as approved by EASA under Approval No. 2005-2514 dated 21 March 2005 refers.

Compliance:

1.    At each pre-flight inspection, following the effective date of this AD.

2.    According to the following schedule:

a.     Initial inspection prior to the next flight following the effective date of this AD; then

b.    Within 50 flight hours plus or minus 5 flight hours Time in Service (TIS) after the effective date of this AD; then

c.     Within 100 flight hours plus or minus 10 flight hours TIS after the effective date of this AD; and then

d.    Repetitively, at the inspection intervals not to exceed 100 flight hours.

3.    a.     For all propellers, irrespective of Time Since New (TSN) - Before further flight if the inspection per Requirement 2 of this AD shows a loss of blade retention nut preload torque below the allowable limits.

b.    For propeller hubs exceeding 500 flight hours TSN on the effective date of this AD:

i.     Prior to the next flight, if ultrasonic or eddy current inspection has not been performed up to now; and then

ii.     Repetitively, at the inspection intervals not to exceed 100 flight hours.

4.    Before further flight.

5.    Before further flight.

This Amendment becomes effective on 7 July 2005.

Background:

An occurrence of the propeller blade separation due to a possible hub failure has been reported.  The cracked propeller hub is still under investigation and therefore no detailed information about the kind of failure is known at the present time.  The actions specified by this Airworthiness Directive are of a precautionary nature and are intended to prevent possible further hub failures.

This amendment introduces an ultrasonic inspection of the propeller hub.

Amendment 2 became effective on 23 December 2005.

James Coyne
Delegate of the Civil Aviation Safety Authority

25 May 2005