23.867 Electrical bonding and protection against lightning and static electricity There is no corresponding rule in CAR 3.
The corresponding airworthiness criteria is section 4.42, Airship Design Criteria, FAA-P-8110-2, Change 2.
Amendment 23-7 and Subsequent
A proposed revision in NPRM 67-14 explains this amendment as follows: “Small airplane operations involving potential exposure to lightning strikes are increasing. The hazardous effects of lightning on aircraft are well known. Economically
practical means of protecting aircraft from such effects have been under study for several years. In order to prevent undue dictation of design, and yet, on the other hand, avoid an unnecessarily vague standard, this proposal summarizes the design objectives derived from the studies and experience obtained in the field of lightning protection of aircraft structures.”
Amendment 23-7 states: “The Final Rule notice proposed to add a new Sec. 23.581 to require lightning protection of the airplane structures. The designation of that amendment has been changed to new Sec. 23.867 since it is a design and construction requirement and should be included in Subpart D of Part 23. One comment objected to the proposal, citing a report regarding a particular airplane which indicated that the recorded lightning strikes on that airplane had not been catastrophic. The report does not, however, cover the numerous other small airplanes and does not establish that lightning strikes would not be catastrophic for small airplanes. Another
commentator suggested that the requirement be applied only to all-weather airplanes. While the term "all-weather" is not defined, service experience has established that lightning strikes occur most frequently along frontal patterns and squall lines in VFR conditions. A third comment stated that the proposal was a satisfactory general statement but that it should be supported by guidance material. General information about lightning and its effect on aircraft is available (Advisory Circular No. AC 20- 53). The FAA believes that the proposal is clear and that no change is warranted. Except for the change in section number, the amendment is adopted as proposed.” Lightning protection of Visual Flight Rules (VFR) airplanes was considered because
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For VFR-only airplanes, an applicant should submit a certification plan that describes the airplane lightning protection design for structure, controls, and systems.
Compliance may be demonstrated by any of the following: Design review, reference to aircraft lightning protection design handbooks, calculations or analysis, lightning test data, or system lightning qualification.
For any other airplane, an applicant should submit a certification test plan describing the analyses or tests to be used to show lightning protection effectiveness. The lightning compliance should, as a minimum, include the following steps:
a. Define the lightning zones for the entire aircraft, and describe the method for determining the zones, such as lightning strike attachment model tests, similarity to previous airplane designs, or service experience.
b. Evaluate the lightning direct effects protection for all flight critical portions of the airframe, flight controls, and propulsion systems. Define the lightning
qualification tests and damage assessment procedures. Fuel system lightning protection compliance should be demonstrated by compliance to 23.954.
c. Evaluate lightning indirect effects protection for the airplane and its electrical and avionics systems. Include both upset and damage assessment for the electrical and avionics systems.
d. Define the test procedures, test parameters, analysis methods simulation techniques, and lightning waveforms and test voltages and currents used to demonstrate the lightning protection compliance.
e. Define the airplane grounding and bonding design features, particularly for composite structures. Demonstrate airplane grounding and bonding tolerance to environments such as vibration, temperature and corrosion.
Define instructions for continued airworthiness of the airplane lightning protection, including maintenance practices and repairs for structure.
The following documents are applicable:
AC 20-155, SAE Documents to Support Aircraft Lightning Protection Certification. This AC states that SAE ARP5412A, Aircraft Lightning Environment and Related Test Waveforms, and ARP5414A, Aircraft Lightning Zoning, are acceptable for certification.
AC 20-53B, Protection of Aircraft Fuel Systems Against Fuel Vapor Ignition Caused by Lightning. This AC addresses ignition hazards caused by direct effects on main and auxiliary fuel tanks, fuel tank components and plumbing, and the indirect effects (upset or damage) on analog or digital electronic and electrical systems that could
lead to ignition hazards on wires or equipment such as fuel quantity probes located in a fuel tank cavity containing fuel vapor.
AC 20-136A, Protection of Aircraft Electrical / Electronic Systems Against the Indirect Effects of Lightning,” December 21, 2006.
SAE ARP 5412A, “Aircraft Lightning Environment and Related Test Waveforms,” February 21, 2005.
SAE ARP 5414A, “Aircraft Lightning Zoning,” February 16, 2005.
SAE ARP 5415A, “Users Manual for Certification of Aircraft Electrical/Electronic Systems for the Indirect Effects of Lightning,” May 14, 2002.
SAE ARP 5416, “Aircraft Lightning Test Methods, “March 17, 2005.
SAE ARP 5577, "Aircraft Lightning Direct Effects Certification,” September 30, 2002.
Amendment 23-49 and Subsequent
A proposed revision in NPRM 94-21 explains the change in the title of § 23.867 as follows: “This proposed revision would change the heading that precedes the section from "Lightning Evaluation" to "Electrical Bonding and Lightning Protection." It would also revise the section heading form "Lightning protection of structures" to "Electrical bonding and protection against lightning and static electricity." The proposed revisions more accurately clarify the content of the section.”
Section 8. Miscellaneous