813 APPENDIX 9
ACRONYMS AC Aircraft Certification AC Advisory Circular ACO Aircraft Certification Office AFM Airplane Flight Manual ASTM American Society of Testing and Materials AWG American Gage Size Conductor BTU British Thermal Unit CFR Code of Federal Regulations ELT Emergency Locator Transmitter FAA Federal Aviation Administration FSSR Flight Standards Service Releases
g. G ravity GPH Gallons Per Hour Hg Mercury HIC Head Injury Criterion NACA National Advisory Committee for Aeronautics NASA National Aeronautics and Space Administration PSI Pounds per Square- inch RTO Rejected Takeoff SAE Society of Automotive Engineers SRP Seat Reference Point STC Supplemental Type Certificate TSO Technical Standard Order TT & L Taxi, Takeoff, and Landing
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815 APPENDIX 10 CROSS REFERENCE FOR PRE-AMENDMENT 25-72 AND POST AMENDMENT 25-72
RELOCATION AND REWORDING OF PERTINENT CRASHWORTHINESS SECTIONS BY AMENDMENT 25-72 NOTE: Only those sections, paragraphs or sub-paragraphs that have been relocated are listed here. If the section, paragraph or sub-paragraph is exactly the same between pre and post amendment 25-72, that section, paragraph or sub-paragraph will not appear in the list below. Minor rewording or revisions will also be listed below.
Pre-amendment 25-72 Post-Amendment 25-72
(b) rewritten (content the same)
25.783(g) minor revision (correct previous error)
25.785(a), relocated from § 25.1307(a), Refer to below
25.785(a) (b)
(b) (c)
(c) (d)
(d) (j)
(e) (k)
(f) (e)
(c) rewritten and part moved to (h)(1), part moved to (h)(6)
(h)(1) (h)(2)
(h)(2)(i) (h)(5)
(h)(2)(ii) (h)(3)
(i) (f) & (f) (1)
(i)(1) (f)(1)
(i)(2) (f)(2)
(i)(3) (f)(3)
(j) (h)(4)
25.785(k) (l)
25.791 separated into 25.791(a) and (b)
25.801(a) revised reference from § 25.807(d) to 25.807(f)
25.803(a) minor rewording
(a) 25.807(d)(6)(ii) and (iii)
(b) minor rewording, added content of 25.803(d), Refer to below
(c)(1) Appendix. J (a)
(c)(2) “ (b)
(c)(3) “ (c)
(c)(4) “ (d)
(c)(5) “ (e)
(c)(6) “ (f) Pre-amendment 25-72 Post-Amendment 25-72
25.803(c)(7) Appendix J (g) with minor rewording
(c)(8) “ (h)
(c)(9) “ (i)
(c)(10) “ (j)
(c)(11) “ (k)
(c)(12) deleted, already in Appendix J, (g)
(c)(13) Appendix J (l)
(c)(14) “ (m)
(c)(15) “ (n)
(c)(16) “ (o)
(c)(17) “ (p)
(c)(18) “ (q)
(c)(19) “ (r)
(c)(20) “ (s)
25.803(d) added to 25.803(c)
25.803(d) is reserved in Amendment 25-72
25.803(e) 25.810(c)
25.803(e) is reserved in Amendment 25-72
25.805 25.807(f) with minor rewording
25.807(a),(a)(1),(a)(2),(a)(3),(a)(4) minor rewording
(a)(7),(a)(7)(i),(a)(7)(ii) (a)(7) with minor rewording
(a)(7)(iii),(a)(7)(iv),(a)(7)(v) 25.813(a)
(a)(7)(vi) 25.785(h)(1)
(a)(7)(vii) 25.813(b),(b)(1),(b)(2)
(a)(7)(viii) 25.810(a),(a)(1)
(a)(7)(ix) 25.810(b) and 25.807(b)
(b) 25.813 and 25.807(c)
(b)(1),(b)(2) 25.807(c)
(c) 25.813 with minor rewording
(c)(1),(c)(2) 25.807(d),(d)(1)
(c)(3) (d)(2)
(c)(4) (d)(3)
(c)(5) (d)(4)
(c)(6) (d)(6)(i)
(c)(7) (d)(7)
(d) (e) with minor rewording
817 Pre-amendment 25-72 Post-Amendment 25-72
25.809(d) 25.809(f)
(e) (g)
(f) 25.810(a)
(g) 25.809(e)
(h) 25.810(d) with minor rewording
(i) 25.809(d)
(j) (h)
25.813(a) revised with additional wording
(b) (b),(b)(1),(b)(2)
25.851(a)(1) 25.851(a)(4)
(a)(2) (a)(5)
(a)(3) (a)(6)
(a)(4) (a)(3)
(a)(5) (a)(1) with minor rewording
(a)(6) (a)(2)
(b),(b)(1) minor rewording
25.853 minor rewording
(d) Appendix F, Part I, (a)(1)(i), with minor rewording (a-1) 25.853©
(b) Appendix F, Part I, (a)(1)(ii), with minor rewording (b-1) Appendix F, Part I, (a)(1)(iii), with minor rewording (b-2) Appendix F, Part I, (a)(1)(iv), with minor rewording (b-3) Appendix F, Part I, (a)(1)(v), with minor rewording
(c) 25.853(b)
(d) part (placard requirement) moved to 25.791(a)
(d)(1) 25.853(d)
(d)(2) 25.791(a)
(e) 25.853(f) plus part (placard requirement) moved to 25.791(c)
(f)* 25.853(e) plus part (placard requirement) moved to
25.791(d) and 25.791(e)* NOTE: * last sentence on lettering size and color has been dropped.
25.855(a) 25.855(d) and Appendix F, Part I (a)(2)(i) with liner requirements moving to 25.855(b) and (c)
818 Pre-amendment 25-72 Post-Amendment 25-72
25.855(a-1) 25.855(b) (a-1)(1) (c) (a-1)(2) (d) and Appendix F, Part I (a)(2)(iii) (a-2) (d) and Appendix F, Part I (a)(2)(iv)
(b) (e)
(c) (f)
(d) (g)
(e) (a), (h) and (i) (Note: first sentence of (e) to (a), second sentence of (e) and (e)(1), (e)(2), (e)(3) to (h), and last sentence of (e) to (i)
25.1307(a) 25.785(a) with minor revision and clarification
25.1359(a) 25.869(a)(1)
(e) (a)(2)
(f) (a)(3)
(g) (a)(4) and Appendix F, Part I (a)(4)
25.1413 (removed by amendment 25-72)
(a) unnecessary duplication of 25.791
(b) and (c) transferred and combined with the same requirements for seats
(d) 25.785(i)
25.1415(a) minor revision Some errors created by Amendment 25-72
25.812(g)(1)(ii) references 25.803(e), should be 25.810(c)
25.812(g)(2) references 25.809(f), should be 25.810(a)
25.812(h) references 25.809(f)(1) and (h), should be 25.810(a) and (d)
25.1411(c) references 25.809(f), should be 25.810(a)
819 APPENDIX 11 FAA MEMORANDUM (latest revision) Certification of Strengthened Flightdeck Doors on Transport Category Airplanes U.S. Department of Transportation Federal Aviation Administration
Subject: INFORMATION: Certification of Strengthened Flightdeck Doors on Transport Category Airplanes Date: Original Release:
November 6, 2001 Revised:
December 3, 2002
From: Manager, Transport Airplane Directorate, ANM-100 Reply to Attn. of: Jeff Gardlin 01-115-11 To: Refer to Distribution This memorandum has been revised to include additional information on § 25.772(b) and information contained in the airplane flight manual.
The events of September 11, 2001, have highlighted the importance of expediting the installation of strengthened flightdeck doors to prevent, or at least delay, entry of unauthorized persons into the flightdeck. To accomplish this goal in a very short time, the Federal Aviation Administration (FAA) promulgated Special Federal Aviation Regulation (SFAR) 92, effective October 9, 2001, and subsequent amendments, SFAR 92-1 through SFAR 92-4, the latest being effective March 19, 2002. While earlier versions of the SFAR only encouraged entities operating under part 121 of 14 CFR to install internal locking devices on their flightdeck compartment doors to resist intrusion by unwanted persons, the latest version requires the installation of these devices. To facilitate rapid improvements to security, all versions of the SFAR allow installations that do not meet all of the airworthiness requirements of Title 14 CFR part 25. At this time, most U.S. operators have installed bars and/or bolts on their flightdeck doors.
These installations have usually resulted in a non-compliance with one or more of the part 25 requirements, typically, the decompression requirements of § 25.365, the egress from the flightdeck requirements of § 25.772, and the entry into the flightdeck requirements of §§ 25.807 and 25.809.
On November 19, 2001, the United States Congress enacted Public Law 107-71, the Aviation and Transportation Security Act, henceforth referred to as the Act. Section 104 of the Act required the FAA to issue requirements to improve flightdeck integrity, specifically the strengthening of the flightdeck door. On January 15, 2002, the FAA
820 issued Amendment 25-106 which adds new intrusion resistance and ballistic penetration requirements to part 25. Concurrently, the FAA also issued Amendment 121-288 that requires part 121 passenger operators that are required to have flightdeck doors, and part 121 cargo operators with flightdeck doors installed on that date, to strengthen these doors. Flightdeck doors on these airplanes must meet these new requirements of part 25 by April 9, 2003.
Supplemental Type Certificate (STC) applications involving flightdeck door modification must address all affected regulatory requirements, including, but not limited to: §§ 25.301, 25.303, 25.305, 25.307, 25.365, 25.571, 25.601, 25.605,
25.607, 25.609, 25.611, 25.613, 25.619, 25.625, 25.771, 25.772, 25.777, 25.789,
25.803, 25.807, 25.809, 25.831, 23.853, 25.855, 25.857, 25.1301, 25.1309, and
25.1581. Final determination of the affected regulatory sections is dependent on the complexity and scope of the modification, and the agreed certification basis of the design change. As stated earlier, all the applicable regulatory sections must be addressed and complied with in order for an applicant to be issued an STC.
The regulations that have been most commonly excepted under SFAR 92-4 (§§ 25.365, 25.772, 25.807, 25. 795, and 25.809) will typically pose the greatest challenge for STC applicants. Additionally, other significant requirements that must be addressed by an STC applicant include the ventilation and smoke requirements of § 25.831, § 25.855, § 25.857, and the flammability requirements of § 25.853.
Information about these requirements and possible acceptable design approaches are discussed in the following paragraphs.
Pressurized Compartment Loads:
Background: Changes in decompression venting integral to the flightdeck door, and in the surrounding flightdeck barrier, must be reviewed to ensure compliance with § 25.365. Airplane decompression requirements include both minimum effective vent areas and maximum opening times for blowout panels or similar decompression venting devices. In cases where the entire flightdeck door functions as a large decompression blowout panel, applicants should consider the impact of additional door locking features on the release time, the reliability of the latching system to release under decompression loads, as well as any increases in opening time due to an increase in door mass, special or additional door hinges, etc. Some of these same concerns apply to smaller decompression blowout panels. Applicants must also address reduced decompression venting area due to the addition of grilles, louvers, or similar features, as well as the direction of the required venting (e.g., from the main cabin to the flightdeck or from the flightdeck to the main cabin).
Failure of a decompression mechanism to function could result in a catastrophic failure of the flightdeck structure. Therefore, if the decompression venting relies on an electrically or mechanically actuated release or opening mechanism, the applicant should
821 conduct qualitative and/or quantitative assessments in accordance with Figure 2, "Depth of Analysis Flowchart," in AC (AC) 25.1309-1A, "System Design and Analysis."
FAQ:
Q: Should the effects of loose articles (e.g., newspapers, magazines, blankets, etc.)
blocking the available flightdeck door flow area through grilles, louvers, grates, or similar features be considered?
A: The intent of CFR 25.365(e) is to establish a minimum design level of strength for floors, bulkheads, partitions and other structure to be able to withstand prescribed decompression scenarios. In particular, CFR 25.365(e)(2) currently establishes a hole size based on fuselage cross-sectional area and is intended to cover different decompression scenarios through one simple and conservative criterion.
Since loose articles are not part of the type design, and their effect cannot be quantified with any certainty, loose articles such as newspapers, magazines, or blankets need not be considered in a decompression analysis. However, if there is something inherent to the airplane design that would become detached or would otherwise be free to block a vent
(e.g., a curtain or a lavatory door), then this should be considered in the analysis.
While the intent of the decompression criteria is to establish a simple and conservative level of strength, certain rational assumptions, such as the use of a discharge coefficient, have historically been accepted and will continue to be accepted. Other assumptions may also be accepted. For example, the flow area restriction formed by the flightdeck glareshield and overhead panel, as would occur in the event of a windshield blowout, may be considered, provided that it is shown that these components will remain intact.
Reliability:
The primary purpose of the door systems is to deter and delay unauthorized entry into the flightdeck without compromising aircraft safety. The flightdeck door systems that are developed to comply with the new § 25.795 requirements must have a reliability level commensurate with the security function intended to support the operational strategies for intruder mitigation. Although the conditional probability of an intruder is not considered extremely high (i.e., this probability is less than one), there should be reasonable confidence that the door will deter and delay any intrusion attempt. Systems used to meet flightdeck intrusion, decompression or other safety related criteria, must meet the applicable requirements of § 25.1309. Guidance on compliance to § 25.1309 is provided in AC 25.1309-1A. Reliability guidance is based on section § 25.1309(b) which states:
The airplane systems and associated components, considered separately and in relation to other systems, must be designed so that:
(1) The occurrence of any failure condition which would prevent the continued safe flight and landing of the airplane is extremely improbable, and
(2) The occurrence of any other failure condition which would reduce the capability of the airplane or the ability of the crew to cope with adverse operating conditions is improbable.
Flightdeck door systems must be shown to comply with §§ 25.1309(b)(1) and (b)(2). In showing compliance with § 25.1309(b)(1) the applicant must consider that the failure of the flightdeck door locking system to unlock during a decompression event may be catastrophic.
If the probability of the decompression event is used then the probability of occurrence must be based on statistically valid data or supporting service experience. Further, the applicant must show the independence between the decompression event and the failure of the system to unlock.
In addition to the decompression scenario, less severe failure conditions such as the crew “lock out” scenarios discussed elsewhere in this Memorandum may become a more stringent requirement and should be assessed when showing compliance to § 25.1309(b)(2).
It is assumed that a failure of the system to lock the door will be detected within one flight. Therefore, the period of latency in this case is reasonable for the failure of the door to unlock. The applicant should provide substantiation that the failure mode is not intermittent. In this case the latency period could be much greater and should factor into the method for showing compliance to § 25.1309(c). Failures of the system to lock the door should be indicated and only be evident to the cockpit crew.
Based on the above rationale, the FAA considers a suitable reliability level to be on the order of 10-5 failure per flight-hour for both lock and unlock operations. Applicants should provide specific rationale if a lower reliability target is requested. This should be accomplished via the issue paper process.
FAQ:
Q: Some designs use decompression panels for venting instead of the opening of the door. Does the above guidance apply to these designs?
A: The reliability target of 10-5 for the door lock and unlock functions is also applicable to the decompression detection and venting functions.
Q: How do you show that a decompression event, a catastrophic event, to be extremely improbably using the 10-5 reliability target?
823 A: There is no agreed probability of occurrence for a decompression event. However, the FAA considers the probability of a decompression event to occur during flight to be much less than 10-4. Using a decompression venting system that is on the order of 10-5 failure per flight-hour, the probability of a catastrophic event becomes extremely improbable (10-9).
Intrusion Protection:
Background: Section 25.795 (a)(1) requires that the flightdeck door installation be designed to resist intrusion by any person who attempts to enter the flightdeck by physically forcing his or her way through the door. The door installation includes the door, its means of attachment to the surrounding structure, and the attachment structure to the bulkhead itself. Of concern are the integrity of the locking/latching/hinge mechanism, any decompression venting panels included as part of the door panel, the door panel itself, and the attachment of the door to the surrounding structure.
It is important to understand that the intent of this regulation is not to make the flightdeck door impenetrable, rather to deter attempts at entry and delay any attempts until other actions can be taken to prevent entry.
Advisory Circular 25.795-1 includes test methods and procedures that result in acceptable methods for demonstrating compliance. Other methods, or deviations from methods described in the AC, may be acceptable to demonstrate compliance.
Alternative compliance methods should be coordinated with the Transport Directorate Staff and documented in an issue paper.
FAQ:
Q: How much of the structure surrounding the door must be representative for the test set-up, and how representative must it be? For example, doors may be installed in airplanes with interior configurations that result in the door being installed on various types of bulkheads from multiple suppliers, with different strength and stiffness characteristics. In some cases, the original mounting structure is no longer available.
A: Section 25.795(a)(1) identifies intrusion requirements for the door installation. The preamble to this amendment states, “the door installation includes the door, its means of attachment to the surrounding structure, and the attachment structure on the bulkhead itself.” Therefore, the test article should be representative of that installation. If the structure to which the door frame attaches is not available, it may be possible to test with the extreme conditions of stiffness (i.e., soft and firm). Conversely, an installation that does not rely on the existing monuments for structural capabilities (strength and stiffness) would avoid this issue.
Q: Do interface loads (static and dynamic) between the door/surround structure need to be collected during the testing? If required, how are these loads applied?
824 A: As discussed above, the relevant structure should be included in the test. If the door, the door frame, and the surround structure to which the door frame is attached is represented in the test, collection of interface loads during testing should not be necessary. Testing that is proposed to be conducted with non-representative structure should be coordinated in advance with the appropriate Aircraft Certification Office. In this case, interface loads may be required to substantiate the installation of the door system.
Ballistic Penetration:
Background: Section 25.795 (a)(2) requires design precautions be taken to minimize the penetration of shrapnel from a fragmentation device and small arms fire which might be fired through the flightdeck doors from occupied compartments. The intent of the ballistic requirements is twofold: (1) to ensure that the integrity of the flightdeck door is not compromised from a ballistic threat that could enable an intruder to gain access to the flightdeck, and (2) to protect the pilot and critical flight instruments from projectiles penetrating into the flightdeck. Again, the intent is not to make the flightdeck “impenetrable,” but to provide a high level of protection.
Advisory Circular 25.795-2 includes test methods and procedures that result in acceptable methods for demonstrating compliance. Other methods, or deviations from methods described in the AC, may be acceptable to demonstrate compliance.
Alternative compliance methods should be coordinated with the Transport Directorate Staff and documented in an issue paper.
FAQ:
Q: How will certification of ballistics labs be handled?
A: There are two ballistics test facilities, U.S. Test Laboratories and H.P. White, that have been accepted by the National Institute of Justice (NIJ) as being capable of conducting tests in accordance with NIJ 0101.04. The FAA has discussed these laboratories qualifications with the NIJ. Based on their qualifications, the FAA will accept either of these laboratories for testing. Conformity inspections would still be required using the normal processes. Other test facilities may be acceptable; however, additional FAA review and oversight will be required. Note, test witnessing may be delegated to the above two laboratories, however, the pass/fail determination will be made by the FAA or an authorized designated engineering representative (DER).
Q: If the door contains decompression panels as part of the design, does the door need to pass the ballistic penetration tests with the panels deployed?
A: The door is not required to provide ballistic penetration protection after a decompression event.
Q: Some designs may contain louvers or openings in panels that are installed at angles greater or less than the 0-30 degree angle required in AC 25.795-2. Since the bullet would be deflected by these louvers/openings and not allow penetration into the