Commonwealth legislation

AD/AC-SNOW/14 Amdt 4 - Wing Spar and Wing Attachments

In ForceCTH

Jurisdiction

Commonwealth

Collection

legislative instrument

Plain English Summary

6/10 complexity

This airworthiness directive requires owners/operators of Ayres Thrush Commander S2 series aeroplanes to carry out regular visual inspections of the lower wing spar, wing main spar and wing attachment hardware, and to retire the wing main spar lower cap by 25,000 hours. Inspections must follow Ayres Service Letter SL-AG-97 and Service Bulletin SB-AG-23.

Inspection intervals vary by condition and are halved for aircraft fitted with FAA STC SA 1463 NM (46.5" wing tip extensions) until fatigue substantiation is supplied; some checks require draining the fuel tank and removing sealant.

JSON API

Deep dive

Want the full deep dive?

Zoe can write the in-depth analysis on top of the summary above: how it works, who it affects and what each part actually does.

Current sections

Direct links to the current provisions in AD/AC-SNOW/14 Amdt 4 - Wing Spar and Wing Attachments.

AD/AC-SNOW/14 Amdt 4 - Wing Spar and Wing Attachments

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES

View image in the official source
Ayres Thrush (Snow) Commander Series Aeroplanes

AD/AC-SNOW/14

Amdt 4

Wing Spar and Wing Attachments 10/95

Applicability: All models S2D, S2R, S2R-R1820, S2R-T15 and S2R-T34.

Requirement: 1. Visually inspect the lower wing spar centre section in accordance with Ayres Corporation Service Letter SL-AG-97.

2. For aircraft listed in Ayres Corporation Service Bulletin SB-AG-23; Inspect the wing main spar and wing attachment hardware in accordance with Ayres Corporation Service Bulletin SB-AG-23, Accomplishment Instructions. Externally inspect the lower surface of the wing from the root rib to the outboard end of the fuel tank for evidence of fuel leakage. If a fuel leak, originating from the wing main spar, is found inspect the forward face of the wing main spar web common to the fuel tank for cracks.

Note: Inspection of the forward face of the wing main spar will require draining of the fuel tank and removal of the fuel tank sealant.

3. Retire the wing main spar lower cap assembly from service.

Compliance: 1. Initially inspect in accordance with Requirement 1 before 2500 hours’ time in service or before 100 hours’ time in service after 14 September 1995, whichever occurs later. Re-inspect at intervals not to exceed 500 hours’ time in service.

2. Initially inspect in accordance with Requirement 2 before 250 hours’ time in service after 14 September 1995 or before 14 September 1996, whichever occurs first. Re-inspect at intervals not to exceed 500 hours’ time in service.

3. Retire, in accordance with Requirement 3, before 25000 hours’ time in service.

For aircraft incorporating FAA STC SA 1463 NM (46.5 inch wing tip extensions) the threshold and interval values for all Requirements are to be halved.

Note: The limitation on STC SA 1463 NM may be lifted by the Authority upon receipt of fatigue and fail safe substantiation data. This limitation does not apply to the Ayres factory designed wing tip extensions.

This amendment is effective 14 September 1995.

Background: The Requirements in this Directive are based on fatigue and fail safe analyses carried out by the manufacturer of the aircraft and service experience. The limitation on STC SA 1463 NM wing tip extensions is imposed as no fatigue analysis for the modified wing has been provided.

This amendment includes inspection of the wing spar and attachment hardware for aircraft built with aluminium spar webs and doublers. A crack in the wing main spar web was found on one aircraft when repairing a fuel leak. The aft face of the spar web is not visible due to the presence of a doubler.

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES

Source text

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

1 AD/AC-SNOW/14 Amdt 4 - Wing Spar and Wing Attachments

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES

Ayres Thrush (Snow) Commander Series Aeroplanes

AD/AC-SNOW/14

Amdt 4

Wing Spar and Wing Attachments 10/95

Applicability: All models S2D, S2R, S2R-R1820, S2R-T15 and S2R-T34.

Requirement: 1. Visually inspect the lower wing spar centre section in accordance with Ayres Corporation Service Letter SL-AG-97.

2. For aircraft listed in Ayres Corporation Service Bulletin SB-AG-23; Inspect the wing main spar and wing attachment hardware in accordance with Ayres Corporation Service Bulletin SB-AG-23, Accomplishment Instructions. Externally inspect the lower surface of the wing from the root rib to the outboard end of the fuel tank for evidence of fuel leakage. If a fuel leak, originating from the wing main spar, is found inspect the forward face of the wing main spar web common to the fuel tank for cracks.

Note: Inspection of the forward face of the wing main spar will require draining of the fuel tank and removal of the fuel tank sealant.

3. Retire the wing main spar lower cap assembly from service.

2. Initially inspect in accordance with Requirement 2 before 250 hours’ time in service after 14 September 1995 or before 14 September 1996, whichever occurs first. Re-inspect at intervals not to exceed 500 hours’ time in service.

3. Retire, in accordance with Requirement 3, before 25000 hours’ time in service.

For aircraft incorporating FAA STC SA 1463 NM (46.5 inch wing tip extensions) the threshold and interval values for all Requirements are to be halved.

This amendment is effective 14 September 1995.