# AD 61-20-02: Exhaust Stack Reinforcement

- Type: Airworthiness directive
- Status: Current
- Products: Piper PA-24-250
- Effective: October 20, 1961
- Published: September 20, 1961
- Issued: December 14, 1961
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Registered aircraft: 1,222 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/9C86C46C99C0A6958625699900507DA7.0001
- DRS record last changed: November 21, 2025
- Page: https://openairdocs.org/ad/61-20-02

## The airworthiness directive

61-20-02 PIPER: Amdt. 336 Part 507 Federal Register September 20, 1961. Applies to Model PA-24 "250" Aircraft Serial Numbers 24-103 to 24-1629 Inclusive, Which Do Not Have a Reinforcing Plate Welded to the Stack in the Area Where the Rear Engine Cylinder Stack is Welded to the Exhaust Stack Assembly.

Compliance required as indicated.

Due to incidents of cracks occurring in the exhaust stack assembly, right side, P/N 21664-03, the following inspections and reinforcement must be accomplished:

  (a) Within 25 hours' time in service after effective date of this AD, remove the carburetor heat shroud assembly, P/N 21664-03, for any indication of cracks or deterioration particularly in the area where the rear engine cylinder exhaust stack is welded to the exhaust stack assembly. If evidence of cracks or deterioration is noted, the assembly must be replaced with a new assembly prior to further flight. The provisions of this paragraph shall be reaccomplished at intervals of50 hours' time in service until such time as the installation in paragraph (b) is accomplished.

  (b) Within 100 hours' time in service after initial compliance with paragraph (a), a clamp-on reinforcement Piper Kit No. 754396 or equivalent, shall be installed on the exhaust stack assembly, P/N 21664-03. After installation of the clamp-on reinforcement, the provisions of paragraph (a) are no longer applicable.

(Piper Service Bulletin 202 dated May 22, 1961, applies to this subject.)

This directive effective October 20, 1961.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 1A15](https://openairdocs.org/tcds/1A15): Piper Aircraft Inc.; names 1 of 4 models: PA-24-250

## 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: 1,222 (1,222 by airframe model, 0 by engine model)
- Makers: Piper 1,222

Models with the most aircraft:

- [Piper PA-24-250](https://openairdocs.org/model/piper-pa-24-250): 1,222 aircraft (airframe model)

All 1 models: https://openairdocs.org/ad/61-20-02/models.md
Every aircraft: https://openairdocs.org/ad/61-20-02/aircraft.md

Its text cites no advisory circulars or STCs.

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