# AD 77-09-02: Windshield Inspection and Repair

- Type: Airworthiness directive
- Status: Current
- Products: Cessna 421B and 421C
- Effective: May 9, 1977
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Amendment: 39-2883
- Registered aircraft: 721 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/6ACC50B90003A2A486256A340068395E.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/77-09-02

## The airworthiness directive

77-09-02 CESSNA: Amendment 39-2883. Applies to Models 421B (Serial Numbers 421B0301 thru 421B0970 except 421B0463, 421B0663 and 421B0962) and 421C (Serial Numbers 421C0001 thru 421C0272 except 421C0224, 421C0232, 421C0246, 421C0260, 421C0261 and 421C0264 thru 421C0271) airplanes.

Compliance: Required as indicated, unless already accomplished.

To prevent separation of the pilot's or co-pilot's windshields from the aircraft, within 50 hours' time in service after the effective date of this AD for those aircraft having 50 hours' or more time in service or upon accumulation of 100 hours' time in service for those aircraft having 49 hours' or less time in service, accomplish either Paragraph A or B below:

A. Windshield Inspection and Repair:

  (1) Visually inspect the pilot's and co-pilot's windshield installation and if necessary, repair in accordance with Cessna Service Letter ME77-5, dated March 14, 1977, or later approved revisions and Windshield Inspection and/or Modification Attachment thereto dated March 11, 1977, or later approved revisions.

  (2) Paragraph A(1) must be accomplished only by maintenance personnel that have been specially trained by Cessna Aircraft Company or its designated representative for this purpose.

NOTE: Owners/operators should contact their local Cessna dealer to schedule their airplane into the nearest Cessna dealership having the specially trained personnel required to accomplish Paragraph A(1).

B. Unpressurized Aircraft Operation:

  (1) Move the cabin pressurization switch to the "unpressurized" position and place adhesive tape over the switch to prevent its movement to the "pressurized" position.

  (2) Fabricate a placard having white 3/16 inch or larger letters on a red background reading: "DO NOT PRESSURIZE CABIN".

  (3) Install the placard fabricated in Paragraph B(2) just above or adjacent to the cabin pressurization switch and operate the aircraft in accordance with this limitation until Paragraph A is accomplished.

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 May 9, 1977.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A7CE](https://openairdocs.org/tcds/A7CE): Textron Aviation Inc.; names 2 of 16 models: 421C, 421B

## 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: 721 (721 by airframe model, 0 by engine model)
- Makers: Cessna 721

Models with the most aircraft:

- [Cessna 421C](https://openairdocs.org/model/cessna-421c): 496 aircraft (airframe model)
- [Cessna 421B](https://openairdocs.org/model/cessna-421b): 225 aircraft (airframe model)

All 2 models: https://openairdocs.org/ad/77-09-02/models.md
Every aircraft: https://openairdocs.org/ad/77-09-02/aircraft.md

Its text cites no advisory circulars or STCs.

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