# AD 56-20-04: Fire Seals

- Type: Airworthiness directive
- Status: Current
- Products: Kelowna Flightcraft R & D 240 Series, 340 and 440
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Registered aircraft: 12 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/70690FF10B0E6DF7862569AB006F0DA4.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/56-20-04

## The airworthiness directive

56-20-04 CONVAIR: Applies to All 240, 340 and 440 Aircraft.

Compliance recommended at the next engine change or airplane overhaul but required not later than December 31, 1957.

Several recent accidents involving nacelle fires have indicated certain deficiencies in the construction of the fire seals between zone 1 and zone 2. To correct this condition the following rework of the present cowling and zone seals is required.

1. Incorporate an additional fireproof seal at the zone 1 to zone 2 shroud-to-cowl seal around the periphery of the diaphragm where the bottom and side cowl meet.

2. Improve the present nacelle seals by incorporating a fireproof seal along the longitudinal juncture of the cowl segments and also improve the present cowl hinge point seals.

3. Replace any existing aluminum material in the zone 2 chimney vent with steel material. (Applicable to CV-240 aircraft only.)

The following Convair Service Bulletins cover acceptable methods of compliance with these modifications: Nos. 240-472 and 340-177 cover item No. 1; Nos. 240-474, 240-481A, 340- 209, 340-210A, 440-30 and 440-32A cover item No. 2; Nos. 240-470 and Revision 1 cover item No. 3. (Compliance with Revision 2 to 240-470 is not required.)

## Affected data sheets (2) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 6A6](https://openairdocs.org/tcds/6A6): Kelowna Flightcraft R & D Ltd.; names 2 of 6 models: 340, 440
- [TCDS A-793](https://openairdocs.org/tcds/A-793): Kelowna Flightcraft R & D Ltd.; names 1 of 1 models: 240 Series

## 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: 12 (12 by airframe model, 0 by engine model)
- Makers: Convair 12

Models with the most aircraft:

- [Convair 340](https://openairdocs.org/model/convair-340): 7 aircraft (airframe model)
- [Convair 440](https://openairdocs.org/model/convair-440): 5 aircraft (airframe model)

All 2 models: https://openairdocs.org/ad/56-20-04/models.md
Every aircraft: https://openairdocs.org/ad/56-20-04/aircraft.md

Its text cites no advisory circulars or STCs.

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