# AD 66-13-04: Pressure Control Static Air System

- Type: Airworthiness directive
- Status: Current
- Products: Learjet 23 and 24
- Effective: May 17, 1966
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Amendment: 39-237
- Registered aircraft: 13 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/BB1467AE853B693B8625696E005425B7.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/66-13-04

## The airworthiness directive

66-13-04 LEARJET: Amdt. 39-237 Part 39 Federal Register May 17, 1966. Applies to Models 23 and 24 Airplanes.

Compliance required before further flight, unless already accomplished, except that the airplane may be flown to a base where the repair can be performed, provided the following restrictions are contained on a placard in clear view of the pilot:

"(a) No passengers may be carried.

"(b) Monitor the cabin pressure indicator for proper pressurization control. If automatic and/or manual control of the cabin pressure is not properly effective:

"(1) Turn air bleed off to shutoff bleed air.

"(2) Reduce power to reduce bleed air pressure as necessary.

"(3) Don oxygen masks.

"(4) Expedite descent to a safe altitude."

Modify the pressure control static air system in accordance with Lear Service Kit SK23/24-230 or an equivalent approved by the Chief, Engineering and Manufacturing Branch, FAA Central Region.

This directive effective upon publication in the Federal Register for all persons except those to whom it was made effective immediately by telegram dated May 10, 1966.

## Affected data sheets (2) (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: 24
- [TCDS A5CE](https://openairdocs.org/tcds/A5CE): Learjet Inc.; names 1 of 1 models: 23

## 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: 13 (13 by airframe model, 0 by engine model)
- Makers: Learjet 13

Models with the most aircraft:

- [Learjet 24](https://openairdocs.org/model/learjet-24): 7 aircraft (airframe model)
- [Learjet 23](https://openairdocs.org/model/learjet-23): 6 aircraft (airframe model)

All 2 models: https://openairdocs.org/ad/66-13-04/models.md
Every aircraft: https://openairdocs.org/ad/66-13-04/aircraft.md

Its text cites no advisory circulars or STCs.

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