# AD 72-18-06: Stabilator Rib Balance Weights

- Type: Airworthiness directive
- Status: Current
- Products: Piper PA-34-200
- Effective: September 9, 1972
- Published: September 9, 1972
- Issued: August 29, 1972
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Amendment: 39-1515
- Registered aircraft: 172 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/2214228A6452084C862569990050F732.0001
- DRS record last changed: November 21, 2025
- Page: https://openairdocs.org/ad/72-18-06

## The airworthiness directive

72-18-06 PIPER: Amendment 39-1515. Applies to Piper PA-34-200 airplanes, Serial Numbers 34-E4, and 34-7250001 through 34-7250335, certificated in all categories.

Compliance required within the next ten hours time in service after the effective date of this AD, unless already accomplished.

To provide a positive means of attachment for stabilator tip balance weights accomplish the following:

  (a) Remove stabilator tips.

  (b) Check the balance weight assembly attached to each exposed stabilator rib for looseness. If outer lead weight can be moved rotationally against the rib by hand, it is considered loose.

  (c) If a balance weight is loose, accomplish paragraph (e) before further flight.

  (d) If balance weights are satisfactorily secured, accomplish paragraph (e) within the next 50 hours time in service after this inspection.

  (e) When required by paragraph (c) or (d), remove each balance weight assembly from its attach rib, by removing the three bolts attaching the balance weight assembly plate to the stabilator rib. Replace the AN3H-26A bolts and the lock nuts which attach the balance weights to the assembly plate with AN3-27A bolts and new lock nuts with an AN970-3 washer under each bolt head and under each lock nut. MS21044N3 (AN365-1032) lock nuts or equivalent are required. A drilled head bolt and safety wire is not necessary. Torque the nuts to 35-40 inch- pounds. If balance weights show any signs of damage they must be replaced also.

NOTE: Attention must be given to insure that the bolt grip length is correct and the nut has proper engagement since the thickness of the lead weights may vary slightly. If necessary, AN3-30A bolts may be substituted for the AN3-27A bolts or AN960-10 washers may be used between the AN970-3 washers and the bolt head and/or between the AN970-3 washer and the lock nut to obtain proper thread engagement.

  (f) Reinstall each balance weight assembly to the attach rib as originally installed and safety wire as required. Reinstall stabilator tips. This procedure will not require rebalancing of the stabilator.

Piper Service Bulletin Number 367 pertains to this same subject.

This amendment becomes effective September 9, 1972 and was effective upon receipt for all recipients of the air mail letter dated August 30, 1972 which contained this amendment.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A7SO](https://openairdocs.org/tcds/A7SO): Piper Aircraft Inc.; names 1 of 5 models: PA-34-200 (Seneca)

## 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: 172 (172 by airframe model, 0 by engine model)
- Makers: Piper 172

Models with the most aircraft:

- [Piper PA-34-200](https://openairdocs.org/model/piper-pa-34-200): 172 aircraft (airframe model)

All 1 models: https://openairdocs.org/ad/72-18-06/models.md
Every aircraft: https://openairdocs.org/ad/72-18-06/aircraft.md

Its text cites no advisory circulars or STCs.

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