# AD 93-23-12: Heating Systems

- Type: Airworthiness directive
- Status: Current
- Products: Learjet 60
- Effective: December 15, 1993
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small/large airplane
- Amendment: 39-8748
- Docket: 93-NM-191-AD
- Registered aircraft: 239 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/50BAD3DAF85B8E78862569890076F33A.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/93-23-12

## The airworthiness directive

93-23-12 LEARJET, INC.: Amendment 39-8748. Docket 93-NM-191-AD.

Applicability: Model 60 airplanes having serial numbers 60-002 through 60-021, inclusive, certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent overheating of the auxiliary cabin and cockpit heaters, which could potentially result in a fire, accomplish the following:

  (a) Within 10 flight hours after the effective date of this AD, deactivate the auxiliary cabin and cockpit heating systems; and install a placard stating, "Cabin and Cockpit Heat Inop" adjacent to the AUX HT Switch (S44) on the co-pilot's switch panel; in accordance with Learjet Alert Service Bulletin SB A60-21-1, dated November 1, 1993.

  (b) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Wichita Aircraft Certification Office (ACO), FAA, Small Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Wichita ACO.

NOTE: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Wichita ACO.

  (c) Special flight permits may be issued in accordance with section 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

  (d) The deactivation and placard installation shall be done in accordance with Learjet Alert Service Bulletin SB A60-21-1, dated November 1, 1993. This incorporation by reference was approved by the Director of the Federal Register, in accordance with 5 U.S.C. 552(a) and 1 CFR part 51, as of December 15, 1993 (58 FR 63060, November 30, 1993). Copies may be obtained from Learjet, Inc., P.O. Box 7707, Wichita, Kansas 67277-7707. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Wichita ACO, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

  (e) This amendment becomes effective on December 15, 1993.

## 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 1 of 29 models: 60

## 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: 239 (239 by airframe model, 0 by engine model)
- Makers: Learjet 239

Models with the most aircraft:

- [Learjet 60](https://openairdocs.org/model/learjet-60): 237 aircraft (airframe model)
- [Learjet 60 XR](https://openairdocs.org/model/learjet-60-xr): 2 aircraft (airframe model)

All 2 models: https://openairdocs.org/ad/93-23-12/models.md
Every aircraft: https://openairdocs.org/ad/93-23-12/aircraft.md

Its text cites no advisory circulars or STCs.

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