# AD 61-21-03: Hydraulic Fluid Gage

- Type: Airworthiness directive
- Status: Current
- Products: Boeing DC-8-11, DC-8-12, DC-8-21, DC-8-31, DC-8-32, DC-8-33, DC-8-41, DC-8-42, DC-8-43, DC-8-51, DC-8-52, DC-8-53 and 15 more
- Effective: October 13, 1961
- Published: October 13, 1961
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Registered aircraft: 8 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/2C9B00FEC1E2932F862569BC007489B1.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/61-21-03

## The airworthiness directive

61-21-03 DOUGLAS: Amdt. 346 Part 507 Federal Register October 13, 1961. Applies to All DC-8 Series Aircraft.

Compliance required within the next 150 hours' time in service after the effective date of this AD.

As a result of recent incidents which have shown the need for effective quantity indication of "reserve" hydraulic fluid in the system reservoir, the following must be accomplished:

Unless already accomplished in accordance with FAA approved technical data, replace or modify in accordance with Douglas Service Bulletin No. DC-8 A29-40 (Reissue No. 1 or later) or FAA approved equivalent, the existing hydraulic quantity gage in the cockpit and the quantity transmitter in the fluid reservoir, to provide a system which will indicate the quantity of reserve hydraulic fluid in the reservoir down to approximately one gallon. The system indication error shall not exceed 10 percent. The dial on the quantity gage shall be marked in a manner which divides the total indicator range into three segments and identifies the three segments, as follows:

Segment Reserve Fluid Quantity in Reservoir NORMAL Full (11.5 gal.) to 4.9 gal. AUX. 4.9 gal. to 1.5 gal. EMER. 1.5 gal. to approx. 1.0 gal.

The exact quantities in gallons need not be marked on the quality indicator. "EMER." need not be shown provided that this segment is otherwise marked in a manner distinctly different from the other segments.

(Douglas Service Bulletin No. DC-8 A29-40 (Reissue No. 1 or later) pertains to this same subject.)

This directive effective October 13, 1961.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 4A25](https://openairdocs.org/tcds/4A25): The Boeing Company; names 27 of 27 models: DC-8-41, DC-8-52, DC-8-61, DC-8-53, DC-8-51, DC-8-63, DC-8-11, DC-8-72F…

## 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: 8 (8 by airframe model, 0 by engine model)
- Makers: Douglas 5, Mcdonnell Douglas 3

Models with the most aircraft:

- [Douglas DC-8-73](https://openairdocs.org/model/douglas-dc-8-73): 2 aircraft (airframe model)
- [Douglas DC-8-73F](https://openairdocs.org/model/douglas-dc-8-73f): 2 aircraft (airframe model)
- [Mcdonnell Douglas DC-8-62](https://openairdocs.org/model/mcdonnell-douglas-dc-8-62): 1 aircraft (airframe model)
- [Mcdonnell Douglas DC-8-63](https://openairdocs.org/model/mcdonnell-douglas-dc-8-63): 1 aircraft (airframe model)
- [Mcdonnell Douglas DC-8-63F](https://openairdocs.org/model/mcdonnell-douglas-dc-8-63f): 1 aircraft (airframe model)
- [Douglas DC-8-72](https://openairdocs.org/model/douglas-dc-8-72): 1 aircraft (airframe model)

All 6 models: https://openairdocs.org/ad/61-21-03/models.md
Every aircraft: https://openairdocs.org/ad/61-21-03/aircraft.md

Its text cites no advisory circulars or STCs.

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