Piper PA-31 Series Aeroplanes
AIRWORTHINESS DIRECTIVE
For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/PA-31/126 Amdt 1. and issues the following AD under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.
AD/PA-31/126
Amdt 3
Elevator Spar 2/2000
Applicability: Models Serial Numbers
PA-31, PA-31-300, and PA-31-325 31-2 through 31-8312019 PA-31-350 31-5001 through 31-8553002
PA-31P-350 31P-8414001 through 31P-8414050
Requirement: Inspect in accordance with either Requirement 1 or Requirement 2 below:
- a. Visually inspect the upper and lower surfaces of the elevator spar, from the outboard hinge to 9-inches (230 mm) inboard of the hinge. Inspect for cracking in the skin, loose rivets, and fretting.
b. (i) Gain access as necessary and perform a detail visual inspection of the rear faces of left and right elevator spar webs at the inboard ends of the outboard hinge doublers (refer to Figure 1, item C).
(ii) Gain access as necessary and perform detail visual inspections of the forward faces of the left and right elevator spar webs at their outboard ends. Pay particular attention to the spar bend radii (refer to Figure 1, items A and B).
If cracks are found, replace elevator spar assembly in accordance with Requirement 3.
Note 1: Installation of access holes in accordance with a scheme approved by a CAR 35 authorised person, may facilitate access for these inspections.
Figure 1: Inspect the forward face of each elevator spar web, including the upper and lower bend radii between rivets ‘A’ and ‘B’. Inspect the rear face of each elevator spar adjacent to rivet ‘C”.
2. Accomplish the following in accordance with the Instructions section of Piper Mandatory Service Bulletin (MSB) 998A, dated August 4 1997:
- Install access holes for the inspection of the elevator spar.
b. Inspect the elevator spar for cracks using a boroscope.
(i) If no cracks are found in the elevator spar during the inspection, reinspect the elevator spars for cracks.
(ii) If cracks are found during the initial inspection or subsequent repetitive inspection, refer to Requirement 3 of this Directive.
3. Replace each elevator or elevator spar assembly with a part of improved design as specified in the “Replacement Elevator P/N” and “Replace Spar P/N” columns of the “Material Required Table” on page 4 of Piper MSB 998A.
Accomplish these replacements in accordance with the applicable maintenance manual.
If one elevator spar assembly is replaced before further flight when a crack is found, the other elevator spar assembly must still be repetitively inspected every 100 hours time in service until replacement at 1,000 hours time in service after the initial inspection or when cracks are found, whichever occurs first.
4. Inspect the elevator ice protection boots for looseness in accordance with the Instructions section of Piper MSB 998A.
If the elevator ice protection boots are loose, reinstall or replace the boots before further flight.
Note 2: FAA AD 99-12-05 Amdt 39-11189 refers.
Compliance: 1. a. Within 10 hours time in service after 12 October 1995, unless previously accomplished in accordance with the previous issues of this Directive.
b. Before further flight if skin cracking, loose rivets, or fretting is found during the Requirement 1.a. inspection; otherwise, before 2,500 hours component time in service or within 100 hours time in service after 20 October 1995, whichever occurs later. Thereafter at intervals not to exceed 100 hours time in service; until replaced by an elevator or elevator spar assembly of improved design.
Note 3: Elevator spars repaired prior to the issue of Amendment 2 of this Directive shall be inspected at intervals not exceeding 100 hours time in service unless otherwise previously approved by the Authority.
2. a. Upon accumulating 2,500 hours time in service on each elevator spar assembly, or within 100 hours time in service after 31 December 1999, whichever occurs later.
b. Reinspect at intervals not to exceed 100 hours time in service; until replaced by an elevator or elevator spar assembly of improved design.
3. Whichever of the following occurs first:
Before further flight on any elevator spar assembly where any cracks are found during inspection; or,
Within 1,000 hours time in service after the first Requirement 2 inspection performed after 31 December 1999 or within 1,000 hours time in service after the next Requirement 1 inspection after 24 February 2000, as applicable.
4. Within 100 hours time in service after 31 December 1999, unless already accomplished.
The compliance times of the previous issue of this Directive remain unchanged by this issue of the Directive, except for the Requirement 3 compliance.
This Amendment becomes effective on 24 February 2000.
Background: There have been numerous reports of cracked PA-31 elevator spars. In several instances, both left and right elevator spars were cracked. In two instances the spar was completely severed, significantly reducing the elevator stiffness and introducing a risk of tailplane flutter.
Amendment 1 removed the requirement to perform X-ray inspections. The visual inspection introduced maintains equivalent safety by mandating a simpler inspection that can be performed more frequently. A threshold for the inspection is also introduced, based on a survey of major defect reports. Figure 1 was revised to provide more guidance on the inspection location.
Amendment 2 was issued in response to an FAA AD which introduces certain inspections and replacement of the elevators or elevator spar assemblies with parts of improved design, either at a certain time period or when cracks are found, whichever occurs first. The on-going repetitive visual inspection requirement of the previous issue of this Directive is retained as an option for operators.
Amendment 3 is issued to clarify the intent of Compliance 3 and Compliance Note 3. Amendment 2 of this Airworthiness Directive became effective on 31 December 1999. The original issue of this Airworthiness Directive became effective on 12 October 1995.
Eugene Paul Holzapfel
Delegate of the Civil Aviation Safety Authority 12 January 2000
The above AD is notified in the Commonwealth of Australia Gazette on 27 January 2000.