# AD 66-27-04: Main Landing Gear Keel Members

- Type: Airworthiness directive
- Status: Current
- Products: Bombardier CL-44D4
- Effective: November 12, 1966
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Amendment: 39-299
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/2F2C8B6439ECE2FA862569A7005A45B3.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/66-27-04

## The airworthiness directive

66-27-04 CANADAIR: Amdt. 39-299 Part 39 Federal Register November 2, 1966. Applies to Model CL-44D4 airplanes.

Compliance required as indicated.

To detect cracks in the main landing gear keel vertical posts and horizontal lower reinforcing angle members in the inboard nacelles, accomplish the following:

  (a) For airplanes incorporating the modification specified in Canadair Service Information Circular No. 247-CL44D4, dated April 9, 1963, within the next 50 hours' time in service after the effective date of this AD, unless already accomplished within the last 450 hours' time in service, and thereafter at intervals not to exceed 500 hours' time in service from the last inspection, visually inspect the vertical post members and nesting angles for cracks.

  (b) For airplanes other than those specified in (a), within the next 50 hours' time in service after the effective date of this AD, unless already accomplished within the last 450 hours' time in service, and thereafterat intervals not to exceed 500 hours' time in service from the last inspection, visually inspect the vertical post members and lower reinforcing angles for cracks, in accordance with paragraphs (a), (b), (c) and (d) of "Inspection Procedure" of Canadair Service Information Circular, Issue No. 2, No. 247-CL44D4, dated May 17, 1966, or later FAA-approved revision or an FAA-approved equivalent.

  (c) If a crack is found during an inspection required by (a) or (b), repair the crack in an FAA-approved manner, or replace the part with a part of the same part number that has been inspected in accordance with this AD and found free of cracks or with an equivalent part approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region, before further flight, except that the airplane may be flown in accordance with FAR 21.197 to a base where the repair can be performed.

  (d) The repetitive inspection of the vertical post members required by (a) and (b) may be discontinued whenthe vertical post members are modified with a modification approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region.

  (e) The repetitive inspection of the nesting angles required by (a) may be discontinued when the modification specified in Canadair Service Information Circular No. 247- CL44D4, dated April 9, 1963, is disassembled, the lower reinforcing angles and nesting angles are visually inspected for cracks and repaired or replaced as necessary in accordance with (c), and reinstalled in accordance with Canadair Service Bulletin CL44-452, dated July 8, 1966, or later FAA-approved revision, or an equivalent approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region.

  (f) The repetitive inspection of the lower reinforcing angle members required by (b) may be discontinued when the lower reinforcing angles are modified in accordance with Canadair Service Bulletin CL44-452, dated July 8, 1966, or later FAA-approved revision, or an equivalent approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region.

  (g) Upon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Engineering and Manufacturing Branch, FAA Eastern Region, may adjust the repetitive inspection intervals specified in this AD to permit compliance at an established inspection period of the operator if the request contains substantiating data to justify the increase for that operator.

This directive effective November 12, 1966.

## 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 1 of 2 models: CL-44D4

## Registered aircraft it may apply to (OpenAirDocs)

No registered aircraft matched the models it names.

Its text cites no advisory circulars or STCs.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.