> U.S. Department\
> of Transportation
>
> **Federal Aviation\
> Administration**
>
> ![](media/image1.png){width="6.305555555555555in"
> height="0.16597222222222222in"}

+----+----------------------------------------+---+-----+----------------+
| Su | [INFORMATION]{.underline}: Policy      |   | Da  | May 9, 2005    |
| bj | Statement on Conducting Component      |   | te: |                |
| ec | Level Tests to Demonstrate Compliance  |   |     |                |
| t: | with §§ 25.785(b) and (d)              |   |     |                |
|    |                                        |   |     |                |
|    | #                                      |   |     |                |
+----+----------------------------------------+---+-----+----------------+
|    |                                        |   |     |                |
+----+----------------------------------------+---+-----+----------------+
| F  | Manager, Transport Airplane            |   | Re  | ANM-03-115-31  |
| ro | Directorate, Aircraft Certification    |   | ply |                |
| m: | Service, ANM-100                       |   | to  |                |
|    |                                        |   | At  |                |
|    |                                        |   | tn. |                |
|    |                                        |   | of: |                |
+----+----------------------------------------+---+-----+----------------+
|    |                                        |   |     |                |
+----+----------------------------------------+---+-----+----------------+
| T  | See Distribution                       |   | R   | §§ 25.785(b)   |
| o: |                                        |   | egu | and (d)        |
|    |                                        |   | lat |                |
|    |                                        |   | ory |                |
|    |                                        |   | R   |                |
|    |                                        |   | efe |                |
|    |                                        |   | ren |                |
|    |                                        |   | ce: |                |
+----+----------------------------------------+---+-----+----------------+
|    |                                        |   |     |                |
+----+----------------------------------------+---+-----+----------------+

> The purpose of this memorandum is to provide Federal Aviation
> Administration (FAA) certification policy on conducting component
> level tests in order to demonstrate compliance with the requirements
> of §§ 25.785(b) and (d). The tests described herein provide a
> standardized approach by which each potentially injurious item located
> within the headstrike zone can be assessed for occupant injury
> potential. These test methods are the product of an Aviation
> Rulemaking Advisory Committee recommendation and are harmonized with
> the Joint Aviation Authorities (JAA) and Transport Canada.
>
> Although this policy memorandum focuses primarily on describing
> component level tests for seatback mounted accessories installed
> within the striking radius of the head, the same test methodologies
> can be applied more generally to any surface or other items that may
> be potentially injurious and are located within the headstrike zone
> (e.g., escape slide bustles, and tables, etc.) that need to be
> addressed for compliance with §§ 25.785(b) and (d).
>
> In addition to §§ 25.785(b) and (d) blunt trauma requirements, some
> aircraft certification bases include the additional (and more
> stringent) requirements of § 25.562(c)(5). For these airplanes,
> protection must also be provided so that the head impact does not
> exceed a head injury criterion (HIC) measurement of 1000 units. The
> tests described herein do not address compliance with § 25.562(c)(5)
> HIC requirements.

## Current Regulatory and Advisory Material

> Section 25.785(b), Amendment 25-88, requires that each seat, berth,
> safety belt, harness, and adjacent part of the airplane at each
> station designated as occupiable during takeoff and landing be
> designed so that a person making proper use of those facilities will
> not suffer serious injury in an emergency landing as a result of
> inertia forces specified in §§ 25.561 and 25.562.
>
> Section 25.785(d), Amendment 25-88, requires, in pertinent part, that
> each occupant of a forward or aft facing seat be protected from head
> injury by the elimination of injurious objects within the striking
> radius of the head.
>
> These same occupant injury protection requirements have existed within
> § 25.785 (with the exception of reference to § 25.562 which was added
> by Amendment 25-64) since the adoption of part 25. As such, the policy
> contained within this memorandum can be utilized for demonstrating
> compliance with § 25.785 at all amendments. This policy cannot,
> however, be used in lieu of HIC testing for airplanes whose
> certification bases specifically require compliance with the
> requirements of § 25.562(c)(5). Attachment 1 provides additional
> information for determining how certification bases considerations
> affect the applicability of the tests described herein.

In order to demonstrate compliance with §§ 25.785(b) and (d), two injury
mechanisms must be examined. The first consideration is blunt trauma
injuries experienced by the occupant resulting from the crash loads.
This policy memorandum describes three impact test methods that can be
used to evaluate blunt trauma injuries. The second injury mechanism is
sharp or injurious edges or features. Sharp or injurious edges or
features could cause additional injury and thus impede occupants from
exiting the airplanes after a crash; they are therefore not acceptable.
They are not allowed as design features of airplane interiors, nor are
they allowed to be formed as a result of the impact tests described
within this policy memo. Both injury mechanisms (i.e., blunt trauma and
sharp or injurious edges or features) must be successfully addressed in
order to make a determination of compliance with the requirements of
§§ 25.785(b) and (d).

> Advisory Circular (AC) 25-17, paragraph 81b(4), as supplemented by FAA
> memorandum dated July 13, 1994, provided a method for demonstrating
> compliance with § 25.785 blunt trauma requirements using a comparative
> bowling ball test. This approach allowed an applicant to compare the
> characteristics of a new (i.e., unapproved) feature against a
> previously approved configuration. If the blunt trauma characteristics
> (measured by bowling ball impact accelerations) associated with the
> new feature were less severe than the previously approved
> configuration, they were considered acceptable. Advisory Circular
> 25-17 also described an assessment of the test article for sharp or
> injurious edges or features post-test.
>
> We recognized that there were shortcomings with the bowling ball test
> policy as it was originally published. Because of these shortcomings,
> we noted in the July 13, 1994, memorandum our intent to develop more
> comprehensive policy on this subject. As such, this policy memorandum
> supersedes the guidance contained in AC 25‑17, paragraphs 81b(4)(i)
> through b(4)(iv) regarding the bowling ball test pass/fail criteria
> and the subsequent FAA memorandum on this same subject, dated July 13,
> 1994.
>
> Likewise, the impact device described in Society of Automotive
> Engineers (SAE) standard J921 essentially performs the same function
> as the bowling ball test and therefore is also no longer acceptable
> for demonstrating compliance with the
>
> requirements of §§ 25.785(b) and (d). This policy memorandum does not
> supersede any of the other methods of compliance pertaining to
> §§ 25.785(b) and (d) contained within\
> AC 25-17. The remaining allowable methods of compliance described in
> AC 25-17 include padding potentially injurious surfaces and relocating
> objects outside of the headstrike zone.
>
> Implementation of this new policy memorandum does not nullify any
> previously completed compliance determinations. However, all new
> compliance determinations should be made in accordance with this
> policy memorandum, the remaining methods of compliance identified in
> AC 25-17, or other methods of compliance established through the issue
> paper process.

## Policy 

> Sections 25.785(b) and (d) require that seatbacks, components mounted
> on the seatbacks (such as video monitors, telephones, cup holders,
> etc.), and any other objects located within the striking radius of the
> head, be designed to prevent serious injury to an occupant whose head
> would impact the objects as a result of the emergency landing inertia
> forces.
>
> We have determined through 16g row to row dynamic tests that seatback
> accessories totaling less than three pounds do not exceed the
> performance criteria described below when installed in seatbacks that
> provide at least one inch of permanent deformation. Industry data
> indicate that "standard" airline passenger seatback designs generally
> provide more than one inch of permanent deformation. As a result, data
> substantiating seatback deformation is not required unless the
> seatback design contains unusual features that significantly increase
> the stiffness beyond that of traditional passenger seats.
>
> If the seatback has been stiffened such that the one-inch permanent
> deformation assumption is questionable, testing may be required. For
> example, a business class pod seat with a separate composite seatback
> privacy shroud would not be considered a "standard" seatback and may
> require further investigation. Standard seatback designs containing
> accessories whose combined weight is less than three pounds can be
> accepted without further assessment for blunt trauma injury potential.
> These items still require assessment for the creation of sharp or
> injurious edges or features resulting from occupant impact.
>
> In order to generate compliance determinations for which the
> objectives may be clearly met, the test methods require, by necessity,
> determinate pass/fail criteria. As noted in this policy, other
> acceptable methods of compliance which may not meet these criteria may
> be proposed. The inclusion of determinate pass/fail criteria is a
> change from the approach that was previously accepted, which allowed
> approval based solely on comparative analysis. This change is
> necessary because the comparative bowling ball test could not
> adequately discriminate between injurious and non-injurious features.
> For example, a traditional seatback could have very effective energy
> absorption characteristics.
>
> However, this very effective energy absorbing seatback could be
> modified to include an item such as an "XYZ brand" video monitor,
> which could result in *slightly* degraded energy absorption
> characteristics. Under these circumstances, applying the guidance
> provided in AC 25-17, as modified by the FAA memorandum dated July 13,
> 1994, would lead one to conclude that the video monitor installation
> was unacceptable.

The converse was also possible; an applicant could present a very rigid
"standard" seatback that provided very little energy-absorbing
capability. Because "standard" seatbacks have been traditionally
accepted as being adequately delethalized by inspection, an applicant
could then show by comparison that the addition of the same "XYZ brand"
video monitor would slightly improve the energy-absorption
characteristics of the seatback assembly due to the somewhat crushable
nature of the video monitor screen. The applicant could then conclude
that the monitor that was determined to be unacceptable in the first
example would be acceptable in the second example, even though the seat
in the first example would provide greater occupant injury protection.
This was not the intent of the previous guidance; therefore, we have
determined that changing to absolute pass/fail criteria is necessary.

[Test Methods]{.underline}

In order to determine whether or not an item is "injurious" from a blunt
trauma perspective, the item should be installed in a seatback and
subjected to an impact test using either a 13 pound bowling ball, a Free
Motion Headform as defined in 49 CFR part 572, subpart L, or a Head
Component Test Device. Schematics describing each type of test and the
corresponding pass/fail criteria are contained in detail in Attachments
2 through 4. If a seatback contains more than one potentially injurious
item, the test should be repeated to strike each potentially injurious
item using one of the test methods described in Attachments 2 through 4.
Under all three test methods potentially injurious features are struck
with a test device simulating a human head traveling at a minimum
velocity of 34 ft./sec. The resulting peak accelerations should not
exceed 200g's, and accelerations in excess of 80g's should not exceed a
cumulative duration of 3.0 milliseconds.

> In addition to the means of compliance described in Attachments 2
> through 4, it remains acceptable to utilize the other means of
> compliance identified above.

#### Considerations for Seat Technical Standard Order (TSO) Authorization Holders 

> We believe that the vast majority of these types of component tests
> will be conducted on seats to address occupant injury considerations.
> When the seat manufacturer (TSO authorization holder) uses a seatback
> accessory manufacturer as a supplier, they assume responsibility for
> the integration of the accessory in the seatback (see AIR-100
> memorandum, Policy and Guidance on the Approval of Electronic
> Components on
>
> Aircraft Seating Systems, dated October 27, 1998). In this case these
> types of tests can be conducted in parallel with the seat TSO
> processes but cannot be approved under the TSO authorization (or
> Letter of Design Approval for foreign manufacturers). If the testing
> is
>
> done in parallel with a TSO approval, we will accept statements made
> by seat TSO authorization holders regarding the pass/fail criteria
> pertaining to the seatback mounted accessories.
>
> The design approval for seatback accessories is not covered by the TSO
> authorization. Instead, the seat TSO design approval only covers the
> mass, location, and means of attachment of seatback accessories.
> Current industry practices show that most seat TSO holders do not wish
> to be held accountable for the design and manufacturing responsibility
> of accessories. In this case, design approval and installation
> approval of the accessories is the responsibility of the seat
> installer, even though the actual integration of the accessories into
> the seats is most likely accomplished by the seat manufacturer.
> Whether responsibility for the approval of the seatback accessories is
> assumed by the TSO holder or the seat installer, it is acceptable for
> seat manufacturers to conduct the tests described in Attachments 2
> through 4 to determine the occupant injury characteristics. In either
> case, adequate test article definition is still required, but can be
> encompassed by the seat manufacturer's quality control system and
> conformity inspection processes.
>
> A statement from the TSO authorization-holding seat manufacturer that
> the seatback-mounted accessories meet the pass/fail criteria described
> in this memorandum along with submittal of the resultant test data
> should be sufficient for the installer to make a determination of
> compliance with §§ 25.785(b) and (d). This may be a specific statement
> or encompassed in a more general statement, but cannot be included in
> the TSO applicant's statement of conformance (per § 21.605(a)(1)), nor
> any other documents associated with the TSO approval (e.g.,
> installation limitations drawing/document).

#### An example of the latter is as follows: The seat installer (e.g., an airplane manufacturer) includes the text from § 25.785(b) and (d) in its seat interface requirements document (or equivalent) that all seat suppliers must meet, and specifically requires that all seatback mounted accessories be evaluated for occupant injury potential (i.e., blunt trauma and sharp or injurious edges) per this memorandum. The seat supplier, upon delivery of the seats, should provide the test data and a statement to the installer that all of the requirements of the interface document have been met, thereby enabling the installer to make a determination that the occupant injury concerns have been adequately addressed.

#### 

#### Sharp and Injurious Edges

> As a result of the impact tests described above, sharp edges may be
> formed that are injurious or may impede egress. This is not
> acceptable. An assessment of sharp or injurious edges must therefore
> be completed for each seatback mounted accessory, or any other
> potentially injurious item located within the headstrike zone to
> determine compliance with the requirements of §§ 25.785(b) and (d).
>
> We recognize that repeated tests may be necessary to develop and
> refine a seat/seatback accessory configuration that meets the occupant
> injury requirements. As such, the costs associated with utilizing
> production quality accessories for repetitive impact tests can become
> prohibitive. In order to help reduce the costs associated with these
> tests, we have determined that blunt trauma evaluations and
> evaluations of sharp and injurious edges or features can be performed
> independently, if so desired. The blunt trauma tests described in
> Attachments 2 through 4 can be conducted utilizing surrogate test
> articles in accordance with FAA Policy Memorandum ANM-03-115-28, dated
> October 2, 2003. Likewise, a component level assessment of sharp and
> injurious edges and features can be made of a seatback accessory by
> itself, if it is rigidly mounted in a test fixture and subjected to
> one of the test methods described in Attachments 2 through 4. If a
> seatback accessory does not show the propensity to create sharp or
> injurious edges when tested in a rigid fixture, this is sufficient to
> find compliance for the article as installed.
>
> If testing with a surrogate test article yields unacceptable blunt
> trauma results, or an accessory develops sharp and injurious edges or
> features characteristics when tested while mounted in a rigid test
> fixture, it may be advantageous to more accurately represent the
> energy-absorbing characteristics of the seat and seatback accessory
> acting together as a system. In these cases it may be necessary to
> conduct the tests described in Attachments 2 through 4 on the
> accessory installed in the seatback assembly. If this testing approach
> still does not yield acceptable results, it remains acceptable to
> conduct testing to meet the HIC requirements of § 25.562(c)(5), and
> thereafter demonstrate that no sharp or injurious features were
> created.

#### Considerations for Airplane Manufacturers and Airplane Modifiers

> An airplane manufacturer/modifier may also utilize the methods
> described above and in Attachments 2 through 4 to determine that
> features located within the striking radius of an occupant's head are
> non-injurious in accordance with §§ 25.785(b) and (d). In these cases,
> the development of an FAA-approved test plan, test article conformity,
> and test witnessing responsibilities must be coordinated with the
> aircraft certification office with oversight responsibility for the
> installation or modification in accordance with FAA Order 8110.4.

## Effect of Policy

> The general policy stated in this document does not constitute a new
> regulation or create what the courts refer to as a "binding norm." The
> office that implements policy should follow this policy when
> applicable to the specific project. Whenever an applicant\'s proposed
> method of compliance is outside this established policy, it must be
> coordinated with the policy issuing office (e.g., through the issue
> paper process or equivalent). Similarly, if the implementing office
> becomes aware of reasons that an applicant's proposal that meets this
> policy should not be approved, the office must coordinate its response
> with the policy issuing office.

Applicants should expect that the certificating officials will consider
this information when making findings of compliance relevant to new
certificate actions. Also, as with all advisory material, this policy
statement identifies one means, but not the only means, of compliance.

**Implementation**

The compliance method discussed in this policy should be applied to
type, amended supplemental, and amended supplemental type certification
programs whose application date is on or after the date the policy is
finalized. For existing certification programs whose application
precedes the date this policy is effective and the methods of compliance
have already been coordinated with and approved by the FAA or their
designee, the applicant may continue to follow the previously acceptable
methods of compliance or choose to follow the guidance contained in this
policy.

/s/

Ali Bahrami

Attachments