AD/SUPP/13 Amdt 1 - Air Equipment Hoists - Earth Bonding

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Supplementary Equipment

AD/SUPP/13

Amdt 1

Air Equipment Hoists - Earth Bonding 1/92

Applicability: Air-Equipment Hoists P/Nos 76370. All variants, up to and including Serial Numbers 493.

Requirement: 1. Measure the motor current limit resistors P/N 709967 with a milliohmmeter - Maximum permissible value is 0.040 OHM for the two resistors in series.

Note: These can be measured on 76370-30 models using the shunt terminals on the hoist control box.

2. Measure the resistor terminals to ground (the resistor mounting plate) with a megohmmeter - Minimum resistance should be 20 Meg OHM.

3. Install bonding cables and carry out a bonding check in accordance with the Lucas Air Equipment Service Bulletin 25-62-0L.

Note 1: Hoists which have already had bonding jumpers installed in accordance with the original issue 1 of this AD are still required to comply with the requirements of Lucas Air Equipment SB 25-62-0L.

Note 2: Bonding resistance checks are to be carried out with a milliohmmeter capable of resolving to 0.002 OHM.

Note 3: Carry out all checks with main connectors disconnected.

Note 4: Compliance with Lucas Air Equipment SB 25-62-0L is considered Mandatory, French DGAC AD 91-125 refers.

4. Examine all relevant documents to identify any hoists which have exhibited a history of slow operation. All hoists which have exhibited a history of slow operation or have blown circuit breakers in operation shall be returned to an approved overhaul facility for internal inspection.

Compliance: 1. For Requirements 1 and 2. In accordance with the original issue of this AD, ie. prior to hoist operations with cable cutter squib installed, after 9 January 1991.

2. For Requirement 3. For installed hoists; prior to 12 March 1992. For uninstalled hoists; prior to installation in an aircraft.

3. For Requirement 4. In accordance with the original issue of this AD, ie. prior to further hoist operations.

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

Background: An electrical failure introducing ground currents in the hoist body may cause an uncommanded cable cut.

In the absence of any advice from the hoist manufacturer of the French DGAC, the original issue of this AD was raised to address the problem.

Both the hoist manufacturer and DGAC have now issued instructions to improve and check the electrical bonding of the hoist installation, and Amendment 1 to this AD has been issued to reflect these instructions.

In addition, Aerospatiale have issued Mandatory Service Bulletins applicable to hoists installed in particular Aerospatiale helicopters. DGAC have also issued Airworthiness Directives mandating compliance with the Aerospatiale SBs. Details and cross reference to corresponding Australian ADs is as follows: