# AD 78-13-04: Fuel Measurement Gauge - Type: Airworthiness directive - Status: Current - Products: True Flight Holdings AA-1, AA-1A and AA-1B - Effective: June 30, 1978 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Small airplane - Amendment: 39-3247 - Registered aircraft: 618 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/A68724F8E19AFF6E86256A38005E819E.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/78-13-04 ## The airworthiness directive 78-13-04 GRUMMAN AMERICAN AVIATION CORPORATION: Amendment 39- 3247. Applies to airplanes Models AA-1, AA-1A, all serial numbers, and AA-1B Serial Number AA-1B 0001 through AA-1B 0542, certificated in all categories. Compliance required within next 200 hours in service after the effective date of this A. D. unless already accomplished. To provide increased visibility and readability of the fuel measurement gauge and thereby to minimize the occurrence of unintentional fuel exhaustion in flight, accomplish the following: (a) Defuel both fuel tanks and gain access to the fuel measurement gauges by removing interior side panels and access panels on the underside of the wing root. Caution: Installation of the float involves opening of the fuel system within the cockpit. Observe appropriate safety practices concerning defueling and fuel system maintenance. (1) Disconnect the line fittings from the top of the gauges, and from inside the wing root, disconnect the measurement gauge fuel supply lines. Also, disconnect primer line on the right gauge. (2) Remove the two (2) screws in each of the four (4) clamps which mount the measurement gauges to the side panels. (3) The measurement gauges may now be disassembled on the bench and each component individually inspected. Figure 1 shows details of the gauge in an exploded view. (4) Place one (1) Grumman Part Number 401129-5 Fuel Float in each gauge, install two (2) new Part Number 14.2 "U" Cup Packings and reassemble in the reverse order. NOTE: To prevent damage from over-tightening, assemble packings to caps and press assemblies onto glass tube until they bottom. Run nuts up equally on both ends until contact is made with caps. Complete assembly by turning each nut 1/4 turn tighter. (5) Install fuel measurement gauges in aircraft and check for leaks. Install interior side panels and access panels on the underside of the wing root. (b) For the purpose of this A. D.this float fuel gauge is not considered an instrument as defined in FAR 1. Therefore, this modification may be accomplished by an appropriately certificated mechanic or repair station notwithstanding the limitations of FAR 65.81(a) and FAR 145.53. (c) An equivalent method of complying with this A. D. is provided by complying with Grumman American Aviation Corporation Service Letter 75-7 dated November 17, 1975. Alternate methods of complying with this A. D. may be used if approved by the Chief, Engineering and Manufacturing Branch, Federal Aviation Administration, Southern Region, Atlanta, Georgia. (d) An airplane may be flown in accordance with FAR 21.197 to a base for the accomplishment of the modifications required by this A. D. This amendment becomes effective June 30, 1978. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS A11EA](https://openairdocs.org/tcds/A11EA): True Flight Holdings LLC; names 3 of 4 models: AA-1A, AA-1, AA-1B ## 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: 618 (618 by airframe model, 0 by engine model) - Makers: American 386, Grumman American Avn. 232 Models with the most aircraft: - [Grumman American Avn. AA-1B](https://openairdocs.org/model/grumman-american-avn-aa-1b): 231 aircraft (airframe model) - [American AA-1A](https://openairdocs.org/model/american-aa-1a): 207 aircraft (airframe model) - [American AA-1](https://openairdocs.org/model/american-aa-1): 153 aircraft (airframe model) - [American AA-1B](https://openairdocs.org/model/american-aa-1b): 26 aircraft (airframe model) - [Grumman American Avn. AA-1A](https://openairdocs.org/model/grumman-american-avn-aa-1a): 1 aircraft (airframe model) All 5 models: https://openairdocs.org/ad/78-13-04/models.md Every aircraft: https://openairdocs.org/ad/78-13-04/aircraft.md Its text cites no advisory circulars or STCs. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.