AD 89-12-01

final rule
Data completeness: 70%

Airworthiness Directives; Learjet Model 24, 25, 28, 29, 35, 36 and 55 Series Airplanes

AD Number
89-12-01
Status
final_rule
Effective Date
Product Category
aircraft
Docket
Unknown
FR Citation
This information is not available.

Applicability

TypeManufacturerModelDetails
aircraft Learjet Inc. 24 Airworthiness Directives; Learjet Model 24, 25, 28, 29, 35, 36 and 55 Series Airplanes
aircraft Learjet Inc. 24A Airworthiness Directives; Learjet Model 24, 25, 28, 29, 35, 36 and 55 Series Airplanes
aircraft Learjet Inc. 24B Airworthiness Directives; Learjet Model 24, 25, 28, 29, 35, 36 and 55 Series Airplanes
aircraft Learjet Inc. 24B-A Airworthiness Directives; Learjet Model 24, 25, 28, 29, 35, 36 and 55 Series Airplanes
aircraft Learjet Inc. 24C Airworthiness Directives; Learjet Model 24, 25, 28, 29, 35, 36 and 55 Series Airplanes
aircraft Learjet Inc. 24D Airworthiness Directives; Learjet Model 24, 25, 28, 29, 35, 36 and 55 Series Airplanes
aircraft Learjet Inc. 24D-A Airworthiness Directives; Learjet Model 24, 25, 28, 29, 35, 36 and 55 Series Airplanes
aircraft Learjet Inc. 24E Airworthiness Directives; Learjet Model 24, 25, 28, 29, 35, 36 and 55 Series Airplanes
aircraft Learjet Inc. 24F Airworthiness Directives; Learjet Model 24, 25, 28, 29, 35, 36 and 55 Series Airplanes
aircraft Learjet Inc. 24F-A Airworthiness Directives; Learjet Model 24, 25, 28, 29, 35, 36 and 55 Series Airplanes

Unsafe Condition

Failure of drag chute upon deployment due to riser manufactured prior to May 1987.

AI-generated summary from the source AD text. Verify against the official source before acting.

Required Actions

Determine the drag chute riser's manufacture date using specified service bulletins. Replace riser with new part number 6600180-16 or earlier dated riser, or install placard stating 'DRAG CHUTE INOPERATIVE' if riser is pre-May 1987. Perform drag chute control system adjustment and functional test after reidentification or replacement.

AI-generated summary from the source AD text. Verify against the official source before acting.

Compliance Time

Within the next 10 hours time-in-service or 2 calendar weeks after the effective date of this AD, whichever occurs first

AI-generated summary from the source AD text. Verify against the official source before acting.

Affected Aircraft

Learjet Model 24 (24-100 through -357), 25 (25-003 through -373), 28 (28-001 through -005), 29 (29-001 through -004), 35 (35-001 through -646), 36 (36-001 through -058), and 55 (55-001 through -134) series airplanes.

AI-generated summary from the source AD text. Verify against the official source before acting.

Source: Official FAA Source ↗

Retrieved: Apr 8, 2026

Rights: U.S. Government Public Domain

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