AD 78-16-03

final rule
Data completeness: 70%

Airworthiness Directives; Learjet Models 23, 24, 24A, 24B, 24B-A, 24C, 24D, 24D-A, 24E, 24F, 24F-A, 25, 25A, 25B, 25C, 25D, 25F 35, 35A, 36, and 36A Airplanes

AD Number
78-16-03
Status
final_rule
Effective Date
Product Category
aircraft
Docket
Unknown
FR Citation
This information is not available.

Applicability

TypeManufacturerModelDetails
aircraft Learjet Inc. 23 Airworthiness Directives; Learjet Models 23, 24, 24A, 24B, 24B-A, 24C, 24D, 24D-A, 24E, 24F, 24F-A, 25, 25A, 25B, 25C, 25D, 25F 35, 35A, 36, and 36A Airplanes
aircraft Learjet Inc. 24 Airworthiness Directives; Learjet Models 23, 24, 24A, 24B, 24B-A, 24C, 24D, 24D-A, 24E, 24F, 24F-A, 25, 25A, 25B, 25C, 25D, 25F 35, 35A, 36, and 36A Airplanes
aircraft Learjet Inc. 24A Airworthiness Directives; Learjet Models 23, 24, 24A, 24B, 24B-A, 24C, 24D, 24D-A, 24E, 24F, 24F-A, 25, 25A, 25B, 25C, 25D, 25F 35, 35A, 36, and 36A Airplanes
aircraft Learjet Inc. 24B Airworthiness Directives; Learjet Models 23, 24, 24A, 24B, 24B-A, 24C, 24D, 24D-A, 24E, 24F, 24F-A, 25, 25A, 25B, 25C, 25D, 25F 35, 35A, 36, and 36A Airplanes
aircraft Learjet Inc. 24B-A Airworthiness Directives; Learjet Models 23, 24, 24A, 24B, 24B-A, 24C, 24D, 24D-A, 24E, 24F, 24F-A, 25, 25A, 25B, 25C, 25D, 25F 35, 35A, 36, and 36A Airplanes
aircraft Learjet Inc. 24C Airworthiness Directives; Learjet Models 23, 24, 24A, 24B, 24B-A, 24C, 24D, 24D-A, 24E, 24F, 24F-A, 25, 25A, 25B, 25C, 25D, 25F 35, 35A, 36, and 36A Airplanes
aircraft Learjet Inc. 24D Airworthiness Directives; Learjet Models 23, 24, 24A, 24B, 24B-A, 24C, 24D, 24D-A, 24E, 24F, 24F-A, 25, 25A, 25B, 25C, 25D, 25F 35, 35A, 36, and 36A Airplanes
aircraft Learjet Inc. 24D-A Airworthiness Directives; Learjet Models 23, 24, 24A, 24B, 24B-A, 24C, 24D, 24D-A, 24E, 24F, 24F-A, 25, 25A, 25B, 25C, 25D, 25F 35, 35A, 36, and 36A Airplanes
aircraft Learjet Inc. 24E Airworthiness Directives; Learjet Models 23, 24, 24A, 24B, 24B-A, 24C, 24D, 24D-A, 24E, 24F, 24F-A, 25, 25A, 25B, 25C, 25D, 25F 35, 35A, 36, and 36A Airplanes
aircraft Learjet Inc. 24F Airworthiness Directives; Learjet Models 23, 24, 24A, 24B, 24B-A, 24C, 24D, 24D-A, 24E, 24F, 24F-A, 25, 25A, 25B, 25C, 25D, 25F 35, 35A, 36, and 36A Airplanes

Unsafe Condition

Failure of the refrigeration condenser fan with part number 6608059-3, which has blades not tapered in thickness from the hub to the tip.

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

Required Actions

Before the next flight, inspect the refrigeration condenser fan part number. If part number 6608059-3 is installed, fabricate and install a placard restricting refrigeration system operation. Replace the fan with part numbers 6608059-1, -2, or -4 to remove the placard and return to normal service.

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

Compliance Time

Before the next flight

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

Affected Aircraft

Learjet Models 23 (SN 23-003+), 24/24A (SN 24-100-24-180), 24B/24B-A (SN 24-181-24-229), 24C/24D/24D-A (SN 24-218, 24-230-24-328), 24E/24F/24F-A (SN 24-329-24-356), 25/25A (SN 25-002-25-066), 25B/25C (SN 25-061, 25-067-25-201, 25-204-25-205), 25D/25F (SN 25-206-25-253), 35 (SN 35-001-35-066), 35A (SN 35-067-35-194), 36 (SN 36-001-36-017), and 36A (SN 36-018-36-040).

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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