AD 87-02-06

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AD Number:
87-02-06
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; Gates Learjet Model 35, 36 and 55 Series Airplanes
Subject:
Engine Mounts
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
02/06/1987
Make:
Learjet Inc.
Model:
35 | 35A (C-21A) | 36 | 36A | 55 | 55B | 55C
Product Type:
Aircraft
Product Subtype:
Small/Large Airplane
Affected AD:
Superseded AD:
Affected By:
Superseded By:
Service/Office:
Office of Primary Responsibility:
CFR Part Reference:
Part 39
Comments:
AIRWORTHINESS DIRECTIVES FINAL RULES: 87-02-06
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-5520

AD NUMBER:   87-02-06

SUBJECT HEADING:   Airworthiness Directives; Gates Learjet Model 35, 36 and 55 Series Airplanes

ACTION:  

SUMMARY:  

DATES:   Effective February 6, 1987.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
87-02-06 GATES LEARJET: Amendment 39-5520. Applies to the following Gates Learjet series airplanes, models/serial numbers listed below, certificated in any category; except those airplanes equipped with Part Number (P/N) 2651034 forward engine mount assembly due to spare replacements:

MODEL	SERIAL NUMBER
35	001 through 522
36	001 through 053
55	001 through 107

Compliance required as indicated, unless previously accomplished.

To ensure the structural integrity of the forward engine mounts, accomplish the following:

A. Prior to the accumulation of 2,400 hours time-in-service or 2,400 landings (whichever occurs first), or within the next 75 hours time-in-service after the effective date of this AD, whichever occurs later, conduct a visual inspection of the installed left and right forward engine mounts in accordance with Paragraph 2A of Gates Learjet Service Bulletin 35/36-71-3 or 55-71-2, both dated January 5, 1987, or later FAA-approved revision, as appropriate.

1. If no cracks are found, repeat the visual inspection at intervals not to exceed 420 hours time-in-service.

2. If cracks are found, inspect or replace as indicated below:

a. For total visible crack length (forward plus aft) of 1.0 inch or more, prior to further flight accomplish one of the following:

(1) Replace cracked mount(s) with P/N 2651034 mount assembly; or

(2) Conduct the magnetic particle inspection and disposition in accordance with paragraph B. of this AD.

b. For total visible crack length (forward plus aft) of less than 1.0 inch, accomplish one of the following:

(1) Replace the cracked mount(s) with P/N 2651034 mount assembly within the next 420 hours time-in-service; or

(2) Conduct the magnetic particle inspection and the next 420 hours time-in-service.

B. Prior to the accumulation of 2,400 hours time-in-service or 2,400 landings (whichever occurs first), or within the next 1,500 hours time-in-service after the effective date of this AD, whichever occurs later, conduct a magnetic particle inspection of the removed left and right engine mounts, in accordance with Paragraph 2B of Gates Learjet Service Bulletin 35/36- 71-3 or 55-71-2, both dated January 5, 1987, or later FAA-approved revisions, as appropriate.

1. If no cracks are found, repeat the inspection at intervals not to exceed 1,500 hours time-in-service.

2. If cracks are found, replace as indicated below:

a. For total crack lengths (forward plus aft) of 3.0 inches or more, replace cracked mount(s) with P/N 2651034 mount assembly prior to further flight.

b. For total crack lengths (forward plus aft) of less than 3.0 inches, replace cracked mount(s) with P/N 2651034 mount assembly within 420 hours time-in-service.

C. The installation of a P/N 2651034 mount assembly constitutes terminating action for the repetitive inspections required by paragraphs A. and B. of this AD.

D. Duplicate copies of the Compliance Response form, included in Gates Learjet Service Bulletins 35/36-71-3 and 55-71-2, both dated January 5, 1987, used for reporting the results of the initial visual and magnetic particle inspections, must be submitted within one week after the inspection to the FAA, Central Region, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas 67209.

E. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD.

F. Alternate means of compliance, which provide an acceptable level of safety, may be used when approved by the Manager, Wichita Aircraft Certification Office, FAA, Central Region.

All persons affected by this directive who have not already received the appropriate service information from the manufacturer may obtain copies upon request to Gates Learjet Corporation, P.O. Box 7707, Wichita, Kansas 67277. This information may be examined at the FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or FAA, Central Region, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Mid- Continent Airport, Wichita, Kansas.

This amendment becomes effective February 6, 1987.

FOOTER: