AD/Enst 28/39 Main Rotor Blade Retention Pin (Cth)

AIRWORTHINESS DIRECTIVE

For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (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.

Enstrom F-28 Series Helicopters

AD/ENST 28/39 Main Rotor Blade Retention Pin 10/2007 DM

Applicability:

Model F-28, F-28A, F-28C, F-28C-2, F-28C-2R, F-28F, F-28F-R, 280, 280C, 280F, 280FX, TH-28, 480, and 480B helicopters, with a main rotor blade retention pin having a serial number that is listed below:

04098-01 through 04098-56
05018-01 through 05018-36
05143-01 through 05143-56
05341-1 through 05341-8
05341-10 through 05341-17
05341-19
05341-21 through 05341-33
05341-35 through 05341-42
05341-44 through 05341-59
05341-61
05341-62
05341-64 through 05341-71
06214-3 through 06214-14
06214-16 through 06214-23
06214-25 through 06214-29
06214-31
06214-33 through 06214-35
06214-37 through 06214-57
06214-59 through 06214-68

Requirement:

1.    Check the serial number that is marked on the head of each main rotor blade retention pin (retention pin) and check if the number is listed in the Applicability section of this Directive.  See Figure 1 for the location of the serial number.  If there is no serial number marked on the head of the retention pin (ie. The retention pin head is blank), the retention pin does not need to be replaced and this determination constitutes a terminating action for the requirements of this Directive for that retention pin.

2.    Determine the number of hours time in service (TIS) for any affected retention pin and replace the retention pin with a serviceable retention pin as follows:

a.     For a retention pin with 545 or more hours TIS, remove the retention pin and replace it with a serviceable retention pin with a serial number that is not listed in the Applicability section of this Directive.

b.    For a retention pin with less than 545 hours TIS, remove the retention pin and replace it with a serviceable retention pin with a serial number that is not listed in the Applicability section of this Directive.

Note 1:  Enstrom Service Directive Bulletin No. T-029, original issue, and Enstrom Service Directive Bulletin No.0102, original issue, or later FAA approved revisions, refer.

Note 2:  FAA AD 2007-16-01 Amdt 39-15140 refers.

Compliance:

1.    Before further flight.

For Requirement 2.a: Within the next 5 hours TIS or within 30 days, whichever occurs first.

For Requirement 2.b: Before reaching 550 hours TIS or within 30 days, whichever occurs first.

This Directive shall be entered on the Maintenance Release as maintenance required. The Requirement 1 serial number check may be performed and certified by the Pilot in Command who has been trained by an appropriately qualified person.  In this case, a copy of this Directive is to be carried in the aircraft.

This Airworthiness Directive becomes effective on 15 August 2007.

Background:

The FAA received a report from the manufacturer that some retention pins were not manufactured in accordance with specifications cited on the engineering drawing. Failure of a retention pin would result in separation of a main rotor blade from the helicopter, and subsequent loss of control.

David Villiers
Delegate of the Civil Aviation Safety Authority

8 August 2007