# AD 63-18-02: Engine Breather

- Type: Airworthiness directive
- Status: Current
- Products: Helio H-391B, H-395 (USAF L-28A or U-10B) and H-395A
- Effective: September 1, 1963
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Registered aircraft: 33 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/BEF97D3718CF4C3286256A38005EE735.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/63-18-02

## The airworthiness directive

63-18-02 HELIO: Amdt. 609 Part 507 Federal Register August 31, 1963. Applies to All Models H-391B, H-395 Serial Numbers 1 to 591, Inclusive, and H-395A Serial Numbers 1 to 1008, Inclusive.

Compliance required prior to September 15, 1963.

To preclude possible loss of engine oil through the vacuum oil separator due to blockage of the engine breather tube with ice or snow, accomplish the following:

Modify the oil breather tube P/N 391-060-317 by slicing a flute cut 18 inches from contour of lower cowl 0.25 to 0.31 inch depth and 0.75 inch in height on aft side of tube. This cut can be added to the present breather tube.

(Helio Service Bulletin No. 30A dated April 20, 1963, covers this same subject.)

This supersedes AD 62-12-05. This directive effective September 1, 1963.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 1A8](https://openairdocs.org/tcds/1A8): Helio Alaska Inc.; names 3 of 9 models: H-395 (USAF L-28A or U-10B), H-395A, H-391B

## 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: 33 (33 by airframe model, 0 by engine model)
- Makers: Helio 33

Models with the most aircraft:

- [Helio H-391B](https://openairdocs.org/model/helio-h-391b): 16 aircraft (airframe model)
- [Helio H-395](https://openairdocs.org/model/helio-h-395): 16 aircraft (airframe model)
- [Helio H-395A](https://openairdocs.org/model/helio-h-395a): 1 aircraft (airframe model)

All 3 models: https://openairdocs.org/ad/63-18-02/models.md
Every aircraft: https://openairdocs.org/ad/63-18-02/aircraft.md

Its text cites no advisory circulars or STCs.

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