# AD 50-40-01: Nose Gear Spindle

- Type: Airworthiness directive
- Status: Current
- Products: Aero Spacelines 377, 377MG and 377SGT
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Registered aircraft: 1 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/F596572CAC89D1438625682A0064871A.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/50-40-01

## The airworthiness directive

50-40-01 BOEING: Applies to all Model 377 Aircraft. A. Compliance required not later than December 15, 1950, unless already accomplished, and at the periodic inspections nearest a 700-hour interval thereafter if not reinforced as indicated below. Thoroughly inspect the nose gear spindle for circumferential cracks in the area adjacent to the weld between the nose gear spindle shaft, P/N 9-13735, and the spindle bearing, P/N 6- 25978. Since these cracks are extremely fine, a close magnaflux, dye penetrant or equivalent inspection is required. (Etching process is not recommended.) If cracks are found, either of the following steps should be taken: (1) Remove the cracks with 3/8-inch diameter grinding tool such that not more than 0.08 inch of the spindle shaft and not more than 0.10 inch of the weld is removed. (Boeing Service Letter No. 94 covers this subject.) If cracks extend beyond these limits the spindle should be reinforced per item (2) below: (2) Reinforcethe nose gear spindle by machining inside of spindle and inserting a 1/2-inch wall steel tube 25-inches long, P/N 5-39516-3. (Boeing Service Letter No. 138A covers this same subject.) B. (P/N 15-22594) Compliance required as indicated. 1. Thoroughly inspect the nose landing gear terminal P/N 15-22594, for cracks in the trapezoidal cutout as soon as practicable, but not later than November 1, 1952, unless already accomplished, and continuing at periodic intervals not to exceed 800 hours thereafter. This cutout is visible by removing the cover plate on the lower end of the strut and turning the nose gear segment. If cracks are found, the strut may be reworked in accordance with item 2 below, and provided cracks are removed, strut may be returned to service. 2. If not already accomplished, at the next landing gear overhaul, grind the sides of the trapezoidal cutout to a 0.50 inch radius at corners to conform to the sketch shown in Boeing's Service Letter 148A. The inspection of item 1 above must also be continued after rework until service experience shows that further cracking will not occur.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A-812](https://openairdocs.org/tcds/A-812): Aero Spacelines Incorporated; names 3 of 3 models: 377, 377MG, 377SGT

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

Models with the most aircraft:

- [Boeing 377MG](https://openairdocs.org/model/boeing-377mg): 1 aircraft (airframe model)

All 1 models: https://openairdocs.org/ad/50-40-01/models.md
Every aircraft: https://openairdocs.org/ad/50-40-01/aircraft.md

Its text cites no advisory circulars or STCs.

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