# AD 74-22-05: Full Valve Stem and Cap Nut

- Type: Airworthiness directive
- Status: Current
- Products: Piper PA-23, PA-23-160, PA-23-235, PA-23-250 (Navy UO-1) and PA-E23-250
- Effective: October 23, 1974
- Published: October 17, 1974
- Issued: October 8, 1974
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Amendment: 39-1991
- Registered aircraft: 1,267 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/14F7572C52D6F2598625699900513F0F.0001
- DRS record last changed: November 21, 2025
- Page: https://openairdocs.org/ad/74-22-05

## The airworthiness directive

74-22-05 PIPER: Amendment 39-1991. Applies to Piper Models PA-23 and PA-23-160. Serial Nos. 23-1 to 23-2046 incl. and PA-23-235, PA-23-250 and PA-E23-250 Serial Nos. 27-1 to 27-3943 incl. except 27-3837.

Compliance required within 100 hours or ninety days after the effective date of this AD, whichever occurs first.

In order to prevent the heater fuel valve stem and cap nut from backing off and spilling fuel, accomplish the following:

a. Inspect the stem and cap nut on Valves P/N's 17781-00 and 19460-00 for proper safetying and secureness in accordance with Apache Service Manual No. 752422, Section 13-138 or Aztec Service Manual No. 753564, Section 13-135 as applicable, and Piper Service Bulletin No. 401 dated May 21, 1974, or subsequent approved revisions, or equivalent methods approved by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region.

b. If the stem and nut are not secure or properly safetied, disassemble and inspect the stem, seat body and threads for damage in accordance with Section 13-135 or 13-138 of the applicable airplane Service Manual. Any part found damaged must be replaced with a serviceable part. Also, replace the cap nut (or the complete assembly if necessary) with a like part which has been drilled for MS20995C41 safety wire, or has equivalent safetying provisions approved by the Chief, Engineering & Manufacturing Branch, FAA, Eastern Region.

c. Re-install valve assembly, safety wire cap nut and pressure check fuel system in accordance with Section 13-136 or 13-139 of applicable Airplane Service Manual and Piper Service Bulletin No. 401, or equivalent methods approved by the Chief, Engineering & Manufacturing Branch, FAA, Eastern Region.

d. Aircraft may be flown to a base where the maintenance required by this Airworthiness Directive may be performed per FAR's 21.197 and 21.199.

This amendment is effective October 23, 1974.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 1A10](https://openairdocs.org/tcds/1A10): Piper Aircraft Inc.; names 5 of 6 models: PA-23-160, PA-23-235, PA-E23-250, PA-23-250 (Navy UO-1), PA-23

## 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: 1,267 (1,267 by airframe model, 0 by engine model)
- Makers: Piper 1,267

Models with the most aircraft:

- [Piper PA-23-250](https://openairdocs.org/model/piper-pa-23-250): 894 aircraft (airframe model)
- [Piper PA-23-160](https://openairdocs.org/model/piper-pa-23-160): 188 aircraft (airframe model)
- [Piper PA-23](https://openairdocs.org/model/piper-pa-23): 155 aircraft (airframe model)
- [Piper PA-23-235](https://openairdocs.org/model/piper-pa-23-235): 25 aircraft (airframe model)
- [Piper PA-23-250 (6PCLM)](https://openairdocs.org/model/piper-pa-23-250-6pclm): 5 aircraft (airframe model)

All 5 models: https://openairdocs.org/ad/74-22-05/models.md
Every aircraft: https://openairdocs.org/ad/74-22-05/aircraft.md

Its text cites no advisory circulars or STCs.

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