CHAPTER 4. MILITARY DEVIATIONS TO FAA-APPROVED TYPE DESIGN
1. Can the FAA establish that uncertified SME (appearing on FAA Form 8130-31 as a military deviation) does not interfere with the airplane and/or flight crew performance for normal operation or a failure case? The FAA and/or FAA designees cannot establish this by making actual compliance findings; however, a technical evaluation or assessment may be provided. Unless it can be established under an FAA-approved process that the system or equipment installed on follow-on aircraft are the same as that evaluated, any evaluation or assessment would apply to the specific serial number examined. Configuration control and applicability of the evaluation for subsequent aircraft would be the responsibility of the MAA.
In accordance with the FAA/Armed Forces MOA, the military may request the FAA evaluate military deviations from FAA-approved type design to determine compatibility with the aircraft systems or flight crew performance. They should make that request to the FAA under technical assistance services and make the aircraft available for such evaluations.
2. Why is it required that the FAA find compliance for an aircraft configuration (as defined in type design) even though that FAA-approved configuration may be superseded by military deviations and may never be produced?
a. To approve design changes to a type-certificated product, a configuration must be defined that will establish that the aircraft meets all applicable airworthiness regulations. So, a design data package can only be approved if the type design is complete and eligible for approval. If the equipment or installation is required by regulations, a compliant configuration must be established. If the military chooses to replace this required equipment with equipment that cannot be certified, it should not be included in the proposed type design. On delivery of the aircraft, that equipment will be identified as a military deviation on FAA Form 8130-31. For non-required, equipment that cannot be shown to comply with civil regulations, “safe-carriage” or “provisions-only” installations can be approved (see Order 8110.101, chapter 8), Equipment installed as “safe-carriage” is shown on the type design as disconnected and having no function;
therefore, the compliance findings to substantiate operation of the equipment need not be addressed. Other compliance findings may be required to establish that the equipment meets crashworthiness and cabin safety requirements. “Provisions-only” installations are designed without the equipment identified at all. Equipment could later be installed by FAA approval if compliance is shown, but the provisions are usually for installation of SME that will appear as a military deviation approved by the MAA.
b. There are other reasons why a fully compliant type design must be defined to support the FAA approval:
(1) There is no requirement, basis, or need for the FAA to identify and address exemptions, develop special conditions, or make equivalent levels of safety findings for MCDA.
If the civil airworthiness regulations are not appropriate, it is the responsibility of the MAA to determine appropriate airworthiness criteria to meet its needs. Deviations from the FAA- approved type design, as documented on Form 8130-31, identify these components for the MAA.
(2) The definition of an FAA-approved type design allows a derivative aircraft to be returned to an FAA-approved configuration at any time. If military deviations are addressed (removal of unapproved equipment and restoration of FAA-approved configuration), the aircraft could conceivably operate as a civil aircraft with a standard airworthiness certificate.
(3) Complete definition of FAA-approved type design, and military deviations thereto, help establish and maintain configuration control for the specific aircraft.
3. Do items identified in the FAA-approved type design, that will not be used in the delivered aircraft, need to be manufactured, conformed, and tested to receive certification?
In accordance with 14 CFR § 21.33, the applicant must “allow the Administrator to make any inspection and any flight and ground test necessary to determine compliance with the applicable requirements of the Federal Aviation Regulations.” This must be handled on a case-by-case basis. If compliance for the type design can be established by inspection of drawings, supporting analyses, and/or similarity to an existing FAA-approved design, it may not be necessary to actually build this hardware for the prototype installation. However, if compliance cannot be determined without a necessary inspection, ground test, or flight test, it may be necessary to manufacture a prototype installation that is later modified, or not used, in the aircraft. The applicant’s certification plan should identify components that it does not plan to manufacture or install and a rationale for suitable means of compliance should be identified.
Appendix A
APPENDIX A Acronyms 14 CFR Title 14 of the Code of Federal Regulations AC Advisory Circular ACO Aircraft Certification Office CAR Civil Aviation Regulations CDA Commercial Derivative Aircraft COTS Commercial Off-The-Shelf ELOS Equivalent Level of Safety GFE Government Furnished Equipment MAA Military Airworthiness Authority MCDA Military Commercial Derivative Aircraft MCO Military Certification Office MOA Memorandum of Agreement MOTS Military Off-The-Shelf PMA Parts Manufacturer Approval SME Special Mission Equipment STC Supplemental Type Certificate TC Type Certificate TSOA Technical Standard Order Authorization A-1
Appendix B
APPENDIX B Discussion of required/essential versus non-required/non-essential electrical equipment There are numerous regulations that have general applicability to equipment on the aircraft and there are regulations that apply to specific equipment or equipment whose function is required by “this subchapter” or “essential for safe operation.” Examples of regulations that apply generally to all electrical equipment are 14 CFR §§ 25.1301, 25.1309(b), and 25.1431. Examples of regulations that apply to electrical equipment “whose functioning is required by this subchapter” or “essential for safe operation” include 14 CFR §§ 25.1309(a) and 25.1353(a).
Equipment, including equipment “not required” or “not essential for safe operation,” must be shown not to adversely affect equipment that is required or essential during normal operation and in the case of failure. For example, for electrical equipment, 14 CFR §§ 25.1309(a), 25.1431(a) and (c), and 25.1353(a) apply to normal operation and, 14 CFR § 25.1309(b) applies to the failure case.
1. Non-Required/Non-Essential GFE/SME - Normal Operation:
a. Effect on non-required/non-essential equipment, reference includes 14 CFR § 25.1301.
(1) 14 CFR § 25.1309(a) does not directly apply; therefore, unless another regulation requires a specific design or qualification envelope, the design or qualification envelopes may be that selected by the modifier and may not necessarily have to be FAA- approved. However, operating limitations ma y be appropriate. Reference 14 CFR § 25.1301, also note 14 CFR § 25.1585(b).
b. Effect on required/essential equipment: Reference 14 CFR §§ [indirect] 25.1309(a), [indirect] 25.1431(a) & (c)], and [direct] 25.1353(a).
(1) For the showing that non-required equipment does not adversely affect required equipment or other electrical equipment essential to safe operation, certain FAA/industry qualification standards may be imposed on the non-required equipment. For example, RTCA/DO-178B and RTCA/DO-160B are applied to non-required electrical equipment, see AC 25-10. This is an indirect applica tion of 14 CFR §§ 25.1309(a) and 25.1431(a) & (c) showing the non-required equipment doesn’t affect required equipment.
2. Required/Essential Equipment (Non-GFE/SME) - Normal Operation: Effect on nonrequired/non-essential GFE/SME [no specific regulation other than 14 CFR § 25.1309(a)]. The scope of this assessment will generally be limited and/or delegated.
3. Required or Non Required/Essential or Non Essential Equipment GFE/SME - Failure Case:
a. Sections in 14 CFR such as §§ 25.1309(b) and 25.1431(a) apply. Note, under 14 CFR § 25.1431(a) critical environmental conditions must be considered when evaluating the failure case of non-required/non-essential equipment on required/essential equipment.
b. The discussions above are limited to 14 CFR part 25. The observations above should be the same for other parts (23, 27, and 29) if the regulations are the same.
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Appendix C
APPENDIX C Example (14 CFR part 25) The installation of a manually wound 24 hour military clock in the passenger cabin, and the clock is purchased from an unapproved distributor.
Requirements: As the clock is fully mechanical and not required, the applicable regulations include, but are not limited to the following:
1. 14 CFR § 21.125(b)(1) and (2): The GFE/SME design will have to be defined in the type design, including acceptance inspections and tests that would likely be required to comply with 14 CFR § 21.125(b)(1)&(2). The inspections and tests for the type design to comply with 14 CFR § 21.125(b)(1)&(2) should be developed to the extent necessary to establish that the compliance findings with respect to 14 CFR §§ 25.561(b), 25.789, 25.853, 25.1301 and 25.1309 are still valid from part to part.
2. 14 CFR § 21.53: Conformity would be normal, i.e., per type design. See paragraph above.
3. 14 CFR §§ 25.561(b), 25.789 and 25.853: Typical certification compliance effort for an item of mass in the cabin. Structural tests and burn tests may be required for certification.
4. 14 CFR § 25.1301: The accuracy and the environmental envelope that the clock is to operate can be specified by the modifier or by an agreement between the modifier and aircraft purchaser
(i.e., whether it needs a second hand, accurate to 1, 0.1 or .01 seconds etc., or needs to meet a military specifications, environmental operating conditions, color, size, etc.). The military or manufacturer’s specifications for the clock may provide adequate information.
5. 14 CFR § 25.1309(a): Defining the performance and qualification standards for this installation relative to 14 CFR § 25.1301 are up to the modifier, and the certification assessment is at the discretion of the FAA. The complian ce effort may be a spot check for functioning by the FAA.
6. 14 CFR §§ 25.671, 25.672, 25.901(c), 25.903(b) 25.1309, 25.1431(a): The clock’s failure does not affect the flight crew or other required equipment. Therefore, there is no FAA reliability requirement other than at the time of certification review “they perform their intended functions” under 14 CFR § 25.1309(a). Defining th e qualification standards for reliability for this installation is up to the modifier and the certification assessment is at the discretion of the FAA. The compliance assessment may be delegated or left to statements from the modifier or the clocks manufacturer, if necessary. The military or manufacturer’s specifications for the clock may provide adequate information.
Note: The above list of regulations is not all-inclusive. For instance, the affect of the weight of the installation would need to be assessed under the performance and structural regulations.
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