Commonwealth legislation

AD/PA-25/36 Amdt 3 - Fuselage Wing Spar Attachment Fittings

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This Directive requires owners/operators of all Piper PA‑25 variants to inspect wing‑spar‑to‑fuselage attachment fittings for cracks and corrosion, using routine close visual checks and, at specified intervals with wings removed, Magnetic Particle Inspection (MPI). Any cracked fitting must be replaced (welding prohibited).

It responds to reported failures that caused wing separation, imposes recurring maintenance/MPI costs and downtime, but two approved STCs can substitute the MPI requirement under their own inspection/fatigue regimes.

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AD/PA-25/36 Amdt 3 - Fuselage Wing Spar Attachment Fittings

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Piper PA-25 (Pawnee) Series Aeroplanes

AD/PA-25/36

Amdt 3

Fuselage Wing Spar Attachment Fittings 11/99

Applicability: PA-25 (PA-25-150 & PA-25-180), PA-25-235 and PA-25-260 aeroplanes all serial numbers.

Requirement: 1. Gain access to the forward wing spar to fuselage and aft wing spar to fuselage attachment fittings. Remove any cracked, flaking or bubbling paint and any chemical build up.

Perform a close detailed visual inspection of the front and rear fuselage tubular cluster wing attach fittings. Inspect for cracks, corrosion and general condition. Pay particular attention to the areas indicated in Figure 1.

2. Remove the wings from the aircraft. Thoroughly clean the forward wing spar fuselage attachment fitting. Carry out the following inspections:

(a) Visually inspect the forward fitting for corrosion and general condition. The bore of the lugs of the fitting should be particularly examined for evidence of corrosion occurring between the lug laminates.

(b) Perform a Magnetic Particle inspection of the forward fittings for cracks in accordance with CAO 108.8 using the magnetic flow technique. Pay particular attention to the areas indicated in Figure 1. Replace any cracked fittings.

Note 1: FAA AD 95-12-01 and FAA AD 93-21-12 refers.

Note 2: In assessing serviceability of a fitting after corrosion removal, consideration should be made of the possibility of corrosion between the laminates. In a number of cracked fittings provided to the Authority, interlaminate corrosion has been significant, even though it was not apparent in the bore of the fitting.

Note 3: Numerous proposals for repair by welding of cracked fittings have been received by CASA, the FAA and the manufacturer. Because of difficulties ensuring complete crack removal and alteration of the strength and fatigue properties of the fitting by welding, repair is not viable, and cracked fittings must be replaced.

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Compliance: 1. Inspect in accordance with Requirement 1 of this Directive within 100 hrs time in service or 900 landings whichever occurs first after 4 January 1996.

Re-inspect at intervals not exceeding 100 hours time in service or 900 landings, whichever occurs first.

Initially inspect in accordance with Requirement 2 of this Directive within 2000 hrs time in service of forward fitting installation or within 100 hrs time in service after 4 January 1996, whichever occurs last;

Re-inspect at intervals not exceeding 500 hrs time in service or 4500 landings, whichever occurs first.

If the forward fitting has been modified in accordance with Gippsland Aeronautics CASA STC 83-8 (Modification GA96-01) or Kosola & Associates Inc FAA STC SA00992AT, then the requirement to carry out Requirement 2 is removed.

However, incorporation of either STC makes the fitting subject to the inspection, maintenance and fatigue limitations in the relevant STC instructions. Further, as the Gippsland Aeronautics fitting is common to the Gippsland Aeronautics GA- 200, any Airworthiness Directives issued against the GA-200 relating to the wing fitting will be applicable to this STC.

Any fitting found cracked is to be replaced before further flight.

Note 4: The Authority is aware of a number of instances where the wing bolts have been overtightened upon wing reinstallation. This combined with poor tolerances between the wing lugs and the fittings can cause the fitting lugs to bend and crack. The need to comply with the appropriate wing installation instructions is emphasised.

This Amendment becomes effective on 4 November 1999.

Background: Two failures of a wing front spar fuselage attachment have been reported. In both cases the wing separated from the aeroplane. Since issue of this Directive, numerous cracked and corroded fittings have been reported.

Amendment 2 extended the interval for inspection with wings removed, and required a magnetic particle inspection in lieu of the previous fluorescent penetrant inspection. The magnetic particle inspection has been demonstrated to be considerably more effective than dye penetrant methods.

Amendment 3 clarifies the inspection requirements and addresses the amended FAA AD. Further, it includes reference to two approved STCs that relieve the Magnetic Particle Inspection.

Amendment 2 of this Directive became effective on 4 January 1996. Amendment 1 of this Directive became effective on 25 May 1995.

The original issue of this Directive became effective in September 1977.

Source text

Sourced from the Federal Register of Legislation (legislation.gov.au), CC BY 4.0.

1 AD/PA-25/36 Amdt 3 - Fuselage Wing Spar Attachment Fittings

Piper PA-25 (Pawnee) Series Aeroplanes