# AD 76-18-07: Inverter Input Power

- Type: Airworthiness directive
- Status: Current
- Products: Learjet 24, 25, 35 and 36
- Effective: September 10, 1976
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Amendment: 39-2714
- Registered aircraft: 40 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/3BF162CE083B67158625696E00542AF4.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/76-18-07

## The airworthiness directive

76-18-07 GATES LEARJET: Amendment 39-2714. Applies to Models 24 (Serial Numbers 24-230 thru 24-331 and 24-333); 25 (Serial Numbers 25-061 and 25-067 thru 25-207); 35 (Serial Numbers 35-001 thru 35-079); and 36 (Serial Numbers 36-001 thru 36-020) airplanes.

Compliance: Required as indicated, unless already accomplished.

To determine that each inverter is connected to the correct power bus, within the next 25 hours' time in service after the effective date of this AD, accomplish the following in accordance with Gates Learjet Service Bulletins SB 24/25-273, dated August 9, 1976, or SB 35/36-24-3, dated August 9, 1976, or later approved revisions, as applicable:

A) Perform inverter operational check as outlined in the aforementioned Service Bulletins.

B) If the electrical system does not operate as indicated re the operational checks required by Paragraph A, rewire the inverter input power wiring per the applicable manufacturer's Service Manual Wiring Diagram and repeat the operational check required by Paragraph A to verify proper operation of the electrical system.

C) Any equivalent method of compliance with this AD must be approved by the Chief, Engineering and Manufacturing Branch, FAA, Central Region.

This amendment becomes effective September 10, 1976.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A10CE](https://openairdocs.org/tcds/A10CE): Learjet Inc.; names 4 of 29 models: 24, 25, 35, 36

## Registered aircraft it may apply to (OpenAirDocs)

Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment.

- Aircraft: 40 (40 by airframe model, 0 by engine model)
- Makers: Gates Lear Jet 30, Learjet 10

Models with the most aircraft:

- [Gates Lear Jet 35](https://openairdocs.org/model/gates-lear-jet-35): 16 aircraft (airframe model)
- [Gates Lear Jet 36](https://openairdocs.org/model/gates-lear-jet-36): 13 aircraft (airframe model)
- [Learjet 24](https://openairdocs.org/model/learjet-24): 7 aircraft (airframe model)
- [Learjet 25](https://openairdocs.org/model/learjet-25): 2 aircraft (airframe model)
- [Gates Lear Jet 25](https://openairdocs.org/model/gates-lear-jet-25): 1 aircraft (airframe model)
- [Learjet 35](https://openairdocs.org/model/learjet-35): 1 aircraft (airframe model)

All 6 models: https://openairdocs.org/ad/76-18-07/models.md
Every aircraft: https://openairdocs.org/ad/76-18-07/aircraft.md

Its text cites no advisory circulars or STCs.

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