# AD 78-01-04: Horizontal Stabilizer

- Type: Airworthiness directive
- Status: Current
- Products: Boeing 707-300 Series, 707-300B Series, 707-300C Series and 707-400 Series
- Effective: March 1, 1978
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Amendment: 39-3132
- Registered aircraft: 6 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/61E1B68E2D80F00886256E0D004A9750.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/78-01-04

## The airworthiness directive

78-01-04 BOEING: Amendment 39-3112 as amended by Amendment 39-3132. Applies to all Boeing 707-300/400/300B/300C series airplanes upon the accumulation of, or with more than 8,000 landings. Visually inspect the horizontal stabilizer center section rear spar upper chord for cracks between terminal fittings in accordance with Boeing Service Bulletin 3331 or with the method specified in paragraph B at the time interval specified in paragraph A below. Chords found cracked are to be reworked in accordance with one of the methods noted in paragraph C or replaced with a chord of the same part number prior to further flight. A. Inspect within the next 375 landings after the effective date of this AD and thereafter at intervals not to exceed 375 landings. Report all cracks found during the initial inspection to the Chief, Engineering and Manufacturing Branch, FAA Northwest Region, noting airplane identification, hours time in service, crack locations and magnitude. B. Inspection may be accomplished by gaining access to the upper rear surface of the center section and examining the exposed surfaces of the upper chord using a bright light and a mirror at the aft upper and lower surfaces of the chord. If indications of a crack are found, eddy-current or penetrant inspection should be used to confirm presence of crack. C. Rework in accordance with one of the following: 1. An FAA approved repair provided by the Boeing Company. 2. A method approved by the Chief, Engineering and Manufacturing Branch, FAA Northwest Region. D. With permission of the Chief, Engineering and Manufacturing Branch, FAA Northwest Region, the airplane may be flown in accordance with FAR 21.197 to a base where the inspection or repair can be accomplished. The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1). All persons affected by this directive who have notalready received these documents from the manufacturer, may obtain copies upon request to Boeing Commercial Airplane Company, P. O. Box 3707, Seattle, Washington 98124. These documents may also be examined at FAA Northwest Region, 9010 East Marginal Way South, Seattle, Washington 98108.

Amendment 39-3112 became effective January 15, 1978. This Amendment 39-3132 becomes effective March 1, 1978.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [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

## 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/78-01-04/models.md
Every aircraft: https://openairdocs.org/ad/78-01-04/aircraft.md

Its text cites no advisory circulars or STCs.

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