# AD 74-05-02: Main Landing Gear Uplock Cylinder

- Type: Airworthiness directive
- Status: Current
- Products: Bombardier CL-44D4 and CL-44J
- Effective: February 26, 1974
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Amendment: 39-1790
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/0036D683BA504567862569A7005E2870.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/74-05-02

## The airworthiness directive

74-05-02 CANADAIR: Amdt. 39-1790. Applies to CL-44-D4 and CL-44-J airplanes certificated in all categories.

Compliance required as indicated.

To prevent cracks in the main landing gear uplock actuator cylinder on the Canadair Models CL-44-D4 and CL-44-J aircraft, resulting in the inability to extend the landing gear, accomplish the following:

1. Prior to accumulation of 3,500 hours time in service on the main landing gear uplock actuator cylinders, modify the aircraft in accordance with Canadair Service Bulletin No. CL-44-D4-381, revised September 28, 1968, observing the shimming requirements of Canadair Service Information Circular No. 317-CL-44-D4, dated August 28, 1964, or in accordance with an equivalent procedure approved by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region.

2. For those aircraft modified as described in paragraph 1, the following apply:

a. An uplock actuator cylinder installed in a primary uplock actuator must be replaced prior to the accumulation of 8,000 hours in service in primary uplock actuators. Service time accumulated on uplock cylinders prior to accomplishment of Canadair Service Bulletin No. CL-44-D4-381, must be counted as part of the aforementioned 8,000 hours.

b. Cylinders removed from primary uplock actuators including unmodified, single cylinder uplock systems, may be used in emergency uplock actuators provided that:

  (a) Cylinders are subjected to a dye-penetrant inspection, and are found to be free from cracks.

  (b) Satisfactory dye-checked cylinders are reidentified to distinguish them from new cylinders.

  (c) Cylinders do not exceed 16,000 hours total combined service time in primary and emergency systems.

c. A new actuator cylinder installed in an emergency uplock system has an unrestricted service life.

This AD supersedes AD 65-04-04.

This amendment is effective February 26, 1974.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 1A20](https://openairdocs.org/tcds/1A20): Bombardier Inc.; names 2 of 2 models: CL-44D4, CL-44J

## Registered aircraft it may apply to (OpenAirDocs)

No registered aircraft matched the models it names.

Its text cites no advisory circulars or STCs.

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