Lightning Certification
Guidance Flowchart: P-Static and Lightning Certification Steps for Transport Category (Part 25) Aircraft
In the aircraft certification world it is easy to get stuck in the quagmire of the various FARs, ACs, and ARPs. That’s why we at EMA® put together a handy flowchart of guidance documents one can use when thinking about precipitation static (P-Static) and Lightning certification steps of a transport category (or part 25 category) aircraft.
The flowchart starts by first listing the CFRs (Code of Federal Regulations) pertaining to:
- Systems Lightning Protection – 14 CFR 25.1316, which encompasses both direct effects and indirect effects of lightning
- Fuel Systems Lightning Protection – 14 CFR 25.954 and 25.981, which also includes direct and indirect effects
- Lightning Protection – 14 CFR 25.581, which includes lightning direct effects
- Precipitation Static – 14 CFR 25.899(a)(3)
From there we list the relevant guidance documents, and the flowchart shows how everything fits together. The flowchart focuses on the Systems Lightning Protection, Fuel Lightning Protection, and Precipitation Static guidance documents.
The table shown below lists the FAR (Federal Aviation Regulations) sections, the related guidance documents and their titles. NOTE: there will be a guidance document for 25.981, Fuel Tank Ignition Prevention, sometime in the future. Currently we are not aware of its release date or its document number.
| Environmental Effect | FAR Section | FAR Description | Guidance Doc Number | Guidance Doc Title |
| Lightning | 25.1316 | Electrical and Electronic Systems Lightning Protection | AC 20-136B | Aircraft Electrical and Electronic System Lighting Protection |
| SAE ARP 5414B | Aircraft Lightning Zoning | |||
| SAE ARP 5412B | Aircraft Lightning Environment and Related Test Waveforms | |||
| SAE ARP 5415A | Certification of Aircraft Electrical/Electronic Systems for the Indirect Effects of Lightning | |||
| SAE ARP 5416A | Aircraft Lightning Test Methods | |||
| SAE ARP 5577 | Aircraft Lightning Direct Effects Certification | |||
| DO-160G Sec. 22 | Environmental Conditions and Test Procedures for Airborne Equipment: Lightning Induced Transient Susceptibility | |||
| DO-160G Sec. 23 | Environmental Conditions and Test Procedures for Airborne Equipment: Lightning Direct Effects | |||
| 25.954 | Fuel System Lightning Protection | AC 20-53B | Protection of Aircraft Fuel Systems Against Fuel Vapor Ignition Caused by Lightning | |
| SAE ARP 4761 | Aerospace Recommended Practice, Guidelines and Method for Conducting the Safety Assessment Process on Civil Airborne Systems and Equipment | |||
| 25.981 | Fuel Tank Ignition Prevention | TBD | Policy Guidance for Lightning Protection for Fuel Tank Structure and Systems | |
| P-Static | 25.899(a)(3) | Electrical Bonding and Protection Against Static Electricity | SAE ARP 5672 | Aircraft Precipitation Static Certification |
| SAE ARP 1870A | Aerospace Systems Electrical Bonding and Grounding for Electromagnetic Compatibility and Safety |
