COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Cessna 400 Series Aeroplanes
AD/CESSNA 400/103
Amdt 2
Wing Spars Delamination and Corrosion 6/95
Applicability: All models 404 and 441.
Requirement: 1. Gain access to the rear spar from CWS 34.25 to CWS 82.3 Port and Starboard and inspect the full area of the laminated spar web for delamination and/or corrosion, between the specified stations using an NDI method acceptable to the Authority.
Note: Qantas NDT Technique U-53 using a Fokker Bond tester is an acceptable method.
2. Repair any detected corrosion in accordance with a scheme approved pursuant to CAR 35. Where an aircraft has been repaired as a result of inspection in accordance with this issue, or previous issues, of this Directive, inspect in accordance with the requirements of the approved repair scheme.
Compliance: a. Unless already accomplished, within forty five days after 03 August 1994; thereafter at intervals not exceeding one year; or
b. As specified in the approved repair scheme.
Spar web replacement and internal corrosion protection in accordance with a scheme approved pursuant to CAR 35 terminates the repeat inspection requirement.
The date for compliance with the initial issue of this Directive was within 30 days after 8 June 1994, for amendment 1 the effective date was 3 August 1994.
This Amendment is effective from 25 May 1995
Background: An Australian operator found substantial delamination and corrosion necessitating replacement of the rear spar web in a number of aircraft. Due to similar construction techniques, and as a precautionary measure, a one time visual inspection was also required on the front and centre spar webs.
Amendment 1 was raised following advice from the manufacturer, and an Australian major maintenance organisation, as well as the results of inspections in accordance with the initial issue of the Directive, which demonstrated the total unreliability of a tap test in one case, and extensive spar cap corrosion in another.
Amendment 2 is raised following the extensive inspections undertaken as a result of Amendment 1. These have shown that the problem is confined to the rear spar web.