# AD 70-26-06: Cracks in Elevator and Rudder Spar

- Type: Airworthiness directive
- Status: Historical
- Products: Piper PA-31 and PA-31-300
- Effective: December 29, 1970
- Superseded by: [AD 2001-06-01](https://openairdocs.org/ad/2001-06-01)
- Product type: Aircraft, Small airplane
- Amendment: 39-1132
- Registered aircraft: 29 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/B5ABD6DCF04637EA862569970058302D.0001
- DRS record last changed: August 7, 2025
- Page: https://openairdocs.org/ad/70-26-06

## The airworthiness directive

70-26-06 PIPER AIRCRAFT: Amdt. 39-1132. Applies to Piper Aircraft Models PA-31 and PA-31-300 Serial Numbers 31-2 through 31-694, certificated in all categories.

Compliance required as indicated.

To detect cracks in the elevator and rudder spars, and elevator butt ribs accomplish the following:

  (a) Within the next 100 hours in service after the effective date of this Airworthiness Directive, unless already accomplished within the last 100 hours in service, and thereafter at intervals not to exceed 100 hours in service, inspect in accordance with Piper Service Bulletin No. 323 dated 21 September 1970 and later changes thereto, or in accordance with an equivalent inspection program approved by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region.

  (b) If cracks are found, the defective parts must be replaced as specified in Piper Service Bulletin No. 323 dated 21 September 1970 and later changes thereto or replaced or repaired in a manner approvedby the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region before further flight, except that the airplane may be flown in accordance with FAR 21.197 to a base where the repair can be made.

  (c) Upon the incorporation of Piper Elevator and Rudder Hinge Installation Kit No. 760 465 or equivalent modification approved by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region, the repetitive inspection required under Paragraph (a) may be discontinued.

  (d) Report the results of inspection findings required by this Airworthiness Directive to the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region, (Reporting approved by Bureau of the Budget under BOB No. 04-R0174).

This amendment is effective December 29, 1970.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A20SO](https://openairdocs.org/tcds/A20SO): Piper Aircraft Inc.; names 2 of 4 models: PA-31, PA-31-300

## Registered aircraft it may apply to (OpenAirDocs)

Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment.

- Aircraft: 29 (29 by airframe model, 0 by engine model)
- Makers: Piper 29

Models with the most aircraft:

- [Piper PA-31](https://openairdocs.org/model/piper-pa-31): 26 aircraft (airframe model)
- [Piper PA-31-300](https://openairdocs.org/model/piper-pa-31-300): 3 aircraft (airframe model)

All 2 models: https://openairdocs.org/ad/70-26-06/models.md
Every aircraft: https://openairdocs.org/ad/70-26-06/aircraft.md

## Related documents

- [AD 2001-06-01](https://openairdocs.org/ad/2001-06-01): Elevator Structure · Piper PA-31, PA-31-300, PA-31-325 and 7 more. Effective May 8, 2001. Supersedes this AD

Its text cites no advisory circulars or STCs.

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