ASTM F2696-08

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: F2696 − 08
StandardPractice for
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Inspection of Airplane Electrical Wiring Systems
This standard is issued under the fixed designation F2696; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Terminology
3.1 Acronyms:
1.1 This practice covers basic inspection procedures for
3.1.1 EWIS—electrical wiring interconnection system
electrical wiring interconnect systems for normal and utility
category aircraft electrical wiring systems.
3.1.2 HIRF—high-intensity radiated fields
1.2 This practice is not intended to replace any instructions 3.1.3 ICA—instructions for continued airworthiness
for continued airworthiness published by the aircraft or acces-
3.1.4 LRU—line-replaceable unit
sory manufacturer or type design holder.
3.1.5 MS—military standard
1.3 The values stated in inch-pound units are to be regarded
3.1.6 MTBF—mean time between failures
as standard. The values given in parentheses are mathematical
3.1.7 PTFE—polytetrafluoroethylene
conversions to SI units that are provided for information only
3.1.8 RF—radio frequency
and are not considered standard.
3.1.9 STC—supplemental type certificate (Federal Aviation
1.4 This standard does not purport to address all of the
Administration)
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
4. Significance and Use
priate safety and health practices and determine the applica-
4.1 The term “electrical system” as used in this practice
bility of regulatory limitations prior to use.
means those parts of the aircraft that generate, distribute, and
use electrical energy, including their support and attachments.
2. Referenced Documents
2 4.2 The satisfactory performance of an aircraft is dependent
2.1 Military Standard:
upon the continued reliability of the electrical system.
MIL-C-85049 Connector Accessories, Electrical, General
Specification for 4.3 Damaged wiring or equipment in an aircraft, regardless
of how minor it may appear to be, cannot be tolerated. It is,
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2.2 FAA Guidance Material:
therefore, important that maintenance be accomplished using
FAA Advisory Circular 33.4-3 Instructions for Continued
the best techniques and practices to minimize the possibility of
Airworthiness; Aircraft Engine High Intensity Radiated
failure.
Fields (HIRF) and Lightning Protection Features
4 4.4 When inspecting and evaluating EWIS, improper
2.3 SAE Documents:
wiring, routing, or repairs shall be corrected regardless of the
SAE ARP1870 Aerospace Systems Electrical Bonding and
origin of the error.
Grounding for Electromagnetic Compatibility and Safety
SAE Aerospace ARP5583 Guide to Certification of Aircraft 4.5 This practice is not intended to supersede or replace any
government specification or specific manufacturer’s instruction
in a High Intensity Radiated Field (Hirf) Environment
regarding electrical system inspection and repair
5. Causes of Wire Degradation
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This practice is under the jurisdiction ofASTM Committee F39 on Normal and
Utility CategoryAirplane Electrical Wiring Systems and is the direct responsibility
5.1 The following are considered the principal causes of
of Subcommittee F39.02 on Inspection, Maintenance, and Repair.
wiring degradation and should be used to help focus mainte-
Current edition approved Jan. 15, 2008. Published February 2008. DOI:
nance programs:
10.1520/F2696-08.
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5.1.1 Vibration—High-vibration areas tend to accelerate
Available from the U.S. Government Printing Office, Superintendent of
Documents, Stop: SSOP, Washington, DC 20402-0001.
degradation over time resulting in “chattering” contacts and
3
Available from Federal Aviation Administration (FAA), 800 Independence
intermittent symptoms. High vibration of tie-wraps or string
Ave., SW, Washington, DC 20591, http://www.faa.gov.
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ties can cause damage to insulation. In addition, high vibration
Available from Society of Automotive Engineers (SAE), 400 Commonwealth
Dr., Warrendale, PA 15096-0001, http://www.sae.org. will exacerbate any existing wire insulation cracking.
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F2696 − 08
5.1.2 Moisture—High-moisture areas generally accelerate 6.1.9 Insufficient clearance between exposed current-
corrosion of terminals, pins, sockets, and conductors. Note that carrying parts and ground or poor insulation of exposed
wiring installed in clean, dry areas with moderate temperatures terminals;
appears to hold up well.
6.1.10 Broken or missing
...