September 04, 2013

U.S. Department of Transportation

Docket Operations

West Building, Room W12-140

1200 New Jersey Avenue, S.E.

Washington, D.C. 20590

Subject: Petition for Exemption,

Delta Engineering for Project ODA-2233-03

Title 14 CFR § 23.1359 (c), amendment 23-49

Subject: Request for immediate exemption from Title 14 CFR §23.1359(c) for the wire and cable located 

within certain metal electronic articles.

Introduction:

In accordance with Title 14 CFR Part 11, Delta Engineering is petitioning for an immediate exemption from Title 

14 CFR § 23.1359 (c) for the wire and cable located within certain metal electronic articles, where the electronic 

article is located in a non-fire zone. Delta Engineering’s STC project, ODA-2233-03 is for the installation of 

various electronic articles in the fuselage, in the cabin, in the Electronics Rack, and under the floor, of a Beech 

Kingair B300 aircraft. Many of the electronic articles are commercial off the shelf articles. 

Title 14 CFR § 23.1359 (c) amendment 23-49 states, “Insulation on electrical wire and electrical cable must be 

self-extinguishing when tested at an angle of 60 degrees in accordance with the applicable portions of Appendix F 

of this part, or other approved equivalent methods. The average burn length must not exceed 3 inches (76 mm) 

and the average flame time after removal of the flame source must not exceed 30 seconds. Drippings from the test 

specimen must not continue to flame for more than an average of 3 seconds after falling.” This regulation does 

not provide relief if the wire or cable is located within a non-flammable metal case, electronic article. 

Based upon requirements of Title 14 CFR § 23.1359 (c) even the electrical wire and cable located within a metal 

case electronic article must be tested per Appendix F. 

Supporting data for the requested exemption:

As provided in FAA Advisory Circular 21-16G the FAA finds the criteria in RTCA DO-160G sufficient for 

compliance with Title 14 CFR Part 25. Within RTCA DO-160G, Section 26.3.3 it is establishes two conditions 

wherein flammability testing is NOT required. As worded the wire and cable within an electronic article that 

meets those conditions would not require flammability testing, even though this maybe contrary to the wording 

provided in Title 14 CFR § 23.1359(c) amendment 23-49. 
When shielded wire assembly, or coaxial cable is tested for compliance the test subjects the flame to the outer 

surface of the shielded wire or coax. When the shielded wire assembly or coaxial cable assembly is found 

compliant additional testing is not conducted on each wire internal to the shielded assembly, or when the coaxial 

cable is found compliant the center insulator and conductor are not separately tested. Likewise should be wire 

and cable within an assembly that would prevent an external flame from propagating internal to the electronic 

article, or an internal flame from being able to propagate externally. 

Proposed Requirements for Equivalent level of safety:

To ensure an equivalent level of safety as provided by Title 14 CFR 23.1359 (c) amendment 23-49, Delta 

Engineering is proposing the following:

Wire and cable located internal to the electronic articles/ metal cased articles located in non-fire zones if 

any of the following conditions are met:

1) The enclosure is constructed of metal (metal finish that is non-flammable), on all sides, and has no 

vent holes.

2) The enclosure is constructed of metal (metal finish that is non-flammable) on five sides and one side is 

constructed of a material that has met 12 second vertical test, and has no vent holes

3) The enclosure is constructed of metal (metal finish that is non-flammable) on all sides and has vent 

holes, provided test and/or analysis substantiates an external fire event cannot propagate to the inside 

of the metal case and subject any of the wire or cable to the flame. The test and/or analysis 

substantiates an internal fire event cannot propagate out of the metal case and subject any external item 

to a fire that would be located within three inches (3”) of the electronic article.

4) The enclosure is constructed of metal (metal finish that is non-flammable) on five sides with vent 

holes and one side is constructed of a material that has met 12 second vertical test, provided test and/or 

analysis substantiates an external fire event cannot propagate to the inside of the metal case and 

subject any of the wire or cable to the flame. The test and/or analysis substantiates an internal fire 

event cannot propagate out of the metal case and subject any external item to a fire that would be 

located within three inches (3”) of the electronic article.
Public Interest:

Granting this request for exemption would benefit the public by not requiring additional articles to be purchased 

to support flammability testing of the wire and cable that is used on the internal of the electronic articles.

Sincerely,

John A. Moritz

Delta Engineering

13 DRBA Way

New Castle County Airport

New Castle, Delaware 19720

Phone (302) 325-9337

E Mail jamoritz@delta-engineering.com