COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Eurocopter AS 355 (Twin Ecureuil) Series Helicopters
AD/AS 355/22 Main Rotor Head, Main Gearbox and Landing Gear
Applicability: All Model AS 355 Helicopters. Requirement: Inspect the following:
- Main Rotor Head in accordance with MET work card 62-20-00-601.
10/86
DM
2. MGB suspension (without removing MGB), check condition of the laminated bearings, MGB struts, in accordance with MET work cards 63-00-00-602 Chapt.
2.2 and 63-00-00-606, paying particular attention to cylindrical section of the struts and the strut bearings for retention.
In addition, check for wrinkling, blistering, nicks (maximum allowable depth of defects 0.2mm). The total area of these defects, within a separation of 150mm, shall be a maximum of 1 square centimetre. Scoring or corrosion may be reworked using 400 grit abrasive paper to a maximum depth of 0.1mm and a maximum length of 40mm.
3. Skid type landing gear in accordance with MET work card 32-13-00-601.
In addition check the deflection of rear spring blade P/N 350A41-1076-20 measured between the upper face of the blade end and a ruler placed on the upper part of the skid must not be less than 85mm. Ensure bars are correctly secured and there is no evidence of movement.
4. Hydraulic shock absorbers in accordance with MET work card 32-13-00-401 Chapt. 3.
In addition disconnect the RH and LH shock absorbers at the clamp secured to the front cross tube, functionally check by sliding the shock absorber from one stop to the other by hand. If there is any jerk in the action fill the shock absorber body, in accordance with MRR work card 32-10-11-701 Chapt. 8, with fluid. If actuation of shock absorber is not possible replace shock absorber. During reassembly ensure the 234mm dimension on fig. 4 of work card 32-13-00-401 is complied with. Identify the location of each clamp by a paint mark on the cross tube.
Compliance: 1 to 4
(a) Within 50 hours time in service after 17 September 1986 or before the
30 September 1986 whichever occurs first and thereafter at any occurrence of self sustained dynamic excitation of the helicopter on the ground; and,
b) At each periodic (T) inspection.
COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Background: After further investigation the manufacturer believes the problem is associated with divergent dynamic excitation which occurred at touch down and made possible by the combined deterioration of several dynamic and structural components which resulted in a frequency coupling between the rotor and the landing gear. This Directive supersedes TELEX AD/AS 355/21.