# AD 70-25-07: Rudder Power Control Unit

- Type: Airworthiness directive
- Status: Current
- Products: Boeing 707-100 Long Body, 707-100B Long Body, 707-100B Short Body, 707-200, 707-300 Series, 707-300B Series, 707-300C Series, 707-400 Series, 720 Series and 720B Series
- Effective: December 11, 1970
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Amendment: 39-1125
- Registered aircraft: 6 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/8E5406699CF9602286256831007351EA.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/70-25-07

## The airworthiness directive

70-25-07 BOEING: Amdt. 39-1125. Applies to Model 707 and 720 Series airplanes listed in Boeing Service Bulletin 2998, dated October 1, 1970, or later FAA approved revisions.

To prevent fluid bypassing within the Rudder Power Control Unit (PCU) accomplish the following:

Within the next 300 hours' time in service after the effective date of this AD, unless previously accomplished, modify the Rudder PCU in accordance with Boeing Service Bulletin 2998, dated October 1, 1970, or later FAA approved revision or an equivalent method approved by the Chief, Aircraft Engineering Division, FAA Western Region.

This amendment becomes effective December 11, 1970.

## Affected data sheets (3) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 4A21](https://openairdocs.org/tcds/4A21): The Boeing Company; names 4 of 4 models: 707-100B Short Body, 707-200, 707-100 Long Body, 707-100B Long Body
- [TCDS 4A26](https://openairdocs.org/tcds/4A26): The Boeing Company; names 4 of 4 models: 707-300B Series, 707-400 Series, 707-300 Series, 707-300C Series
- [TCDS 4A28](https://openairdocs.org/tcds/4A28): The Boeing Company; names 2 of 2 models: 720B Series, 720 Series

## 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: 6 (6 by airframe model, 0 by engine model)
- Makers: Boeing 6

Models with the most aircraft:

- [Boeing 707-338C](https://openairdocs.org/model/boeing-707-338c): 2 aircraft (airframe model)
- [Boeing 707-368C](https://openairdocs.org/model/boeing-707-368c): 1 aircraft (airframe model)
- [Boeing 707-321B](https://openairdocs.org/model/boeing-707-321b): 1 aircraft (airframe model)
- [Boeing 707-323B](https://openairdocs.org/model/boeing-707-323b): 1 aircraft (airframe model)
- [Boeing 707-351B](https://openairdocs.org/model/boeing-707-351b): 1 aircraft (airframe model)

All 5 models: https://openairdocs.org/ad/70-25-07/models.md
Every aircraft: https://openairdocs.org/ad/70-25-07/aircraft.md

Its text cites no advisory circulars or STCs.

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