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
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.
2. 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.
Overview
The Piper PA-25 (Pawnee) Series Aeroplanes Airworthiness Directive AD/PA-25/36, initially enacted in 1977, addresses safety concerns regarding the wing spar attachments of the Piper PA-25 aircraft series. This legislative instrument, issued under the Civil Aviation Regulations 1998 by the Civil Aviation Safety Authority (CASA), aims to mitigate the risk of wing separation by mandating rigorous inspection and maintenance protocols. The directive was introduced in response to reported failures and subsequent separations of the wing from the fuselage, primarily due to corrosion and cracks in the wing spar attachment fittings. The policy objective is to ensure the continued airworthiness of these aircraft by preventing structural failures through regular and detailed inspections. This directive has undergone several amendments, with the most recent one, Amendment 3, becoming effective on 4 November 1999, emphasising the importance of thorough inspections and the replacement of any compromised fittings to maintain safety standards.
Scope and Application
This piece of legislation, F2006B05572 (Legislative instrument) applies to the Piper PA-25 (Pawnee) series aeroplanes, specifically the PA-25-150, PA-25-180, PA-25-235, and PA-25-260 models of all serial numbers. The legislation pertains to the mandatory inspection and maintenance requirements for the fuselage wing spar attachment fittings of these aeroplanes. It is a national regulation issued by the Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations 1998, applying across the Commonwealth of Australia. The legislation outlines specific inspection and maintenance procedures for the forward and aft wing spar to fuselage attachment fittings, including the removal of cracked, flaking, or bubbling paint and chemical build-up, detailed visual inspections, and magnetic particle inspections for cracks in accordance with Civil Aviation Order (CAO) 108.8. The directive mandates inspections at certain intervals, with initial inspections to occur within specific timeframes or flight hours, and subsequent inspections at intervals not exceeding certain limits. The legislation also addresses modifications to the wing spar attachment fittings and the applicability of other airworthiness directives.
Key Provisions
The key provisions of this piece of legislation, specifically the Airworthiness Directive (AD) AD/PA-25/36 Amendment 3, focus on the maintenance and inspection requirements for the Piper PA-25 (Pawnee) Series Aeroplanes. Section 1 of the AD mandates that the forward wing spar to fuselage and aft wing spar to fuselage attachment fittings must be inspected and cleaned of any cracked, flaking or bubbling paint and chemical buildup. Section 2 requires a detailed visual inspection of these fittings, checking for cracks, corrosion, and general condition, with particular attention to areas indicated in Figure 1. Additionally, the wings must be removed, and the forward wing spar fuselage attachment fitting must be cleaned and inspected for corrosion, with a magnetic particle inspection conducted for cracks in accordance with Civil Aviation Order (CAO) 108.8.
The AD imposes several obligations on the operators and maintenance personnel of the Piper PA-25 series aeroplanes. Operators must ensure that the inspections are conducted within the specified intervals: initially within 100 hours time in service or 900 landings, whichever occurs first, after 4 January 1996, and then re-inspected at intervals not exceeding 100 hours time in service or 900 landings. The inspection of the forward fitting must be conducted within 2000 hours time in service of the forward fitting installation or within 100 hours time in service after 4 January 1996, whichever occurs last, and re-inspected at intervals not exceeding 500 hours time in service or 4500 landings. Operators must also ensure that any cracked fittings are replaced before further flight, and must comply with the appropriate wing installation instructions to prevent overtightening of wing bolts which could cause fitting lugs to bend and crack.
Failure to comply with the requirements of the AD may result in serious safety hazards, as evidenced by the reported failures of the wing front spar fuselage attachment leading to the wing separating from the aeroplane. The AD does not explicitly state penalties for non-compliance, but non-compliance with Civil Aviation Safety Regulations could result in enforcement actions by the Civil Aviation Safety Authority (CASA). These actions may include fines, suspension or revocation of airworthiness certificates, or other regulatory actions deemed necessary to ensure compliance and maintain air safety standards. The severity of penalties can vary based on the nature and extent of the non-compliance, but they are intended to enforce strict adherence to the safety requirements outlined in the AD.