[Federal Register Volume 64, Number 184 (Thursday, September 23, 1999)]
[Rules and Regulations]
[Pages 51424-51430]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-24792]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM155; Special Conditions No. 25-148-SC]


Special Conditions: Boeing Model 767-300 Series Airplanes; Seats 
with Inflatable Lapbelts

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: These special conditions are issued for Boeing Model 767-300 
series airplanes. These airplanes as modified by Am-Safe, Inc. will 
have novel and

[[Page 51425]]

unusual design features associated with seats with inflatable lapbelts. 
The applicable airworthiness regulations do not contain adequate or 
appropriate safety standards for this design feature. These special 
conditions contain the additional safety standards that the 
Administrator considers necessary to establish a level of safety 
equivalent to that established by the existing airworthiness standards.

EFFECTIVE DATE: October 25, 1999.

FOR FURTHER INFORMATION CONTACT: Jeff Gardlin, Airframe and Cabin 
Safety Branch, ANM-115, Transport Airplane Directorate, Aircraft 
Certification Service, FAA, 1601 Lind Avenue SW., Renton, Washington 
98055-4056; telephone (206) 227-2136; facsimile (425) 227-1149.

SUPPLEMENTARY INFORMATION:

Background

    On March 8, 1999, Am-Safe Inc. 240 North 48th Avenue, Phoenix, 
Arizona, 85043, applied for a supplemental type certificate to install 
inflatable lapbelts for head injury protection on certain seats in 
Boeing Model 767-300 series airplanes. The Model 767-300 series 
airplane is a swept-wing, conventional-tail, twin-engine, turbofan-
powered transport. The inflatable lapbelt is designed to limit occupant 
forward excursion in the event of an accident. This will reduce the 
potential for head injury, thereby reducing the Head Injury Criteria 
(HIC) measurement. The inflatable lapbelt behaves similarly to the 
fixed mounted airbag, but in this case the airbag is integrated into 
the lapbelt, and deploys away from the seated occupant. While airbags 
are now standard in the automotive industry, the use of an inflatable 
lapbelt is novel for commercial aviation.
    Title 14 Code of Federal Regulations (14 CFR) 25.785 requires that 
occupants be protected from head injury by either the elimination of 
any injurious object within the striking radius of the head, or by 
padding. Traditionally, this has required a set back of 35'' from any 
bulkhead or other rigid interior feature or, where not practical, 
specified types of padding. The relative effectiveness of these means 
of injury protection was not quantified. With the adoption of Amendment 
25-64 to 14 CFR part 25, a new standard that quantifies required head 
injury protection was created.
    Title 14 CFR 25.562 specifies that dynamic tests must be conducted 
for each seat type installed in the airplane. In particular, the 
regulations require that persons not suffer serious head injury under 
the conditions specified in the tests, and that a HIC measurement of 
not more than 1,000 units be recorded, should contact with the cabin 
interior occur. While the test conditions described in this section are 
specific, it is the intent of the requirement that an adequate level of 
head injury protection be provided for crash severity up to and 
including that specified.
    While Amendment 25-64 is not part of the Model 767-300 
certification basis, it is recognized that the installation of 
inflatable lapbelts will eventually be proposed for airplanes that do 
include this requirement. In addition HIC is the only available 
quantifiable measure of head injury protection. Therefore, the FAA will 
require that a HIC of less than 1,000 be demonstrated for occupants of 
seats incorporating the inflatable lapbelt.
    Because 25.562 and associated guidance do not adequately address 
seats with inflatable lapbelts, the FAA recognizes that appropriate 
pass/fail criteria need to be developed that do fully address the 
safety concerns specific to occupants of these seats.
    The inflatable lapbelt has two potential advantages over other 
means of head impact protection. First, it can provide significantly 
greater protection than would be expected with energy absorbing pads, 
for example, and second, it can provide essentially equivalent 
protection for occupants of all stature. These are significant 
advantages from a safety standpoint, since such devices will likely 
provide a level of safety that exceeds the minimum standards of the 
Federal Aviation Regulations (FAR). Conversely, airbags in general are 
active systems, and must be relied upon to activate properly when 
needed, as opposed to an energy absorbing pad or upper torso restraint 
that is passive, and always available. These potential advantages must 
be balanced against the potential disadvantages in order to develop 
standards that will provide an equivalent level of safety to that 
intended by the regulations.
    The FAA has considered the installation of inflatable lapbelts to 
have two primary safety concerns: First, that they perform properly 
under foreseeable operating conditions, and second, that they do not 
perform in a manner or at such times as would constitute a hazard to 
the airplane or occupants. This latter point has the potential to be 
the more rigorous of the requirements, owing to the active nature of 
the system. With this philosophy in mind, the FAA has considered the 
following as a basis for the special conditions.
    The inflatable lapbelt will rely on electronic sensors for 
signaling and pyrotechnic charges for activation so that it is 
available when needed. These same devices could be susceptible to 
inadvertent activation, causing deployment in a potentially unsafe 
manner. The consequences of such deployment must be considered in 
establishing the reliability of the system. Am-Safe, Inc. must 
substantiate that the effects of an inadvertent deployment in flight 
are either not a hazard to the airplane, or that such deployment is an 
extremely improbable occurrence (less than 10-9 per flight 
hour). The effect of an inadvertent deployment on a passenger or 
crewmember that might be positioned close to the airbag should also be 
considered. The person could be either standing or sitting. A minimum 
reliability level will have to be established for this case, depending 
upon the consequences, even if the effect on the airplane is 
negligible.
    The potential for an inadvertent deployment could be increased as a 
result of conditions in service. The installation must take into 
account wear and tear so that the likelihood of an inadvertent 
deployment is not increased to an unacceptable level. In this context, 
an appropriate inspection interval and self-test capability are 
considered necessary. Other outside influences are lightning and high 
intensity electromagnetic fields (HIRF). Since the sensors that trigger 
deployment are electronic, they must be protected from the effects of 
these threats. Existing Special Conditions No. 25-ANM-18 regarding 
lightning and HIRF are therefore applicable. For the purposes of 
compliance with those special conditions, if inadvertent deployment 
could cause a hazard to the airplane, the airbag is considered a 
critical system; if inadvertent deployment could cause injuries to 
persons, the airbag should be considered an essential system. Finally, 
the airbag installation should be protected from the effects of fire, 
so that an additional hazard is not created by, for example, a rupture 
of the pyrotechnic squib.
    In order to be an effective safety system, the airbag must function 
properly and must not introduce any additional hazards to occupants as 
a result of its functioning. There are several areas where the airbag 
differs from traditional occupant protection systems, and requires 
special conditions to ensure adequate performance.
    Because the airbag is essentially a single use device, there is the 
potential that it could deploy under crash conditions that are not 
sufficiently severe as to require head injury protection from the 
airbag. Since an actual crash is frequently composed of a series of 
impacts before the airplane

[[Page 51426]]

comes to rest, this could render the airbag useless if a larger impact 
follows the initial impact. This situation does not exist with energy 
absorbing pads or upper torso restraints, which tend to provide 
protection according to the severity of the impact. Therefore, the 
airbag installation should be such that the airbag will provide 
protection when it is required, and will not expend its protection when 
it is not needed. There is no requirement for the airbag to provide 
protection for multiple impacts, where more than one impact would 
require protection.
    Since each occupant's restraint system provides protection for that 
occupant only, the installation must address seats that are unoccupied. 
It will be necessary to show that the required protection is provided 
for each occupant regardless of the number of occupied seats, and 
considering that unoccupied seats may have lapbelts that are buckled.
    Since a wide range of occupants could occupy a seat, the inflatable 
lapbelt should be effective for a wide range of occupants. The FAA has 
historically considered the range from the fifth percentile female to 
the ninety-fifth percentile male as the range of occupants that must be 
taken into account. In this case, the FAA is proposing consideration of 
a larger range of occupants, due to the nature of the lapbelt 
installation and its close proximity to the occupant. In a similar 
vein, these persons could have assumed the brace position, for those 
accidents where an impact is anticipated. Test data indicate that 
occupants in the brace position may not require supplemental 
protection, and so it would not be necessary to show that the 
inflatable lapbelt will enhance the brace position. However, the 
inflatable lapbelt must not introduce a hazard in that case if it 
deploys into the seated, braced occupant.
    Another area of concern is the use of seats so equipped by children 
whether lap-held, in approved child safety seats, or occupying the seat 
directly. The installation needs to address the use of the inflatable 
lapbelt by children, either by demonstrating that it will function 
properly, or by adding appropriate limitation on usage.
    Since the inflatable lapbelt will be electrically powered, there is 
the possibility that the system could fail due to a separation in the 
fuselage. Since this system is intended as crash/post-crash protection 
means, failure due to fuselage separation is not acceptable. As with 
emergency lighting, the system should function properly if such a 
separation occurs at any point in the fuselage. A separation that 
occurs at the location of the inflatable lapbelt would not have to be 
considered.
    Since the inflatable lapbelt is likely to have a large volume 
displacement, the inflated bag could potentially impede egress of 
passengers. Since the bag deflates to absorb energy, it is likely that 
an inflatable lapbelt would be deflated at the time that persons would 
be trying to leave their seats. Nonetheless, it is considered 
appropriate to specify a time interval after which the inflatable 
lapbelt may not impede rapid egress. Ten seconds has been chosen as a 
reasonable time since this corresponds to the maximum time allowed for 
an exit to be openable. In actuality, it is unlikely that an exit would 
be prepared this quickly in an accident severe enough to warrant 
deployment of the inflatable lapbelt, and the inflatable lapbelt will 
likely deflate much quicker than ten seconds.

Type Certification Basis

    Under the provisions of 14 CFR 21.101, Am-Safe, Inc. must show that 
the Model 767-300 series airplanes, as changed, continue to meet the 
applicable provisions of the regulations incorporated by reference in 
Type Certificate No. A1NM or the applicable regulations in effect on 
the date of application for the change. The regulations incorporated by 
reference in the type certificate are commonly referred to as the 
``original type certification basis.'' The regulations incorporated by 
reference in Type Certificate No. A1NM are as follows: Amendments 25-1 
through 25-45 with exceptions. The U.S. type certification basis for 
the Model 767-300 is established in accordance with 14 CFR 21.29 and 
21.17 and the type certification application date. The U.S. type 
certification basis is listed in Type Certificate Data Sheet No. A1NM.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., 14 CFR part 25 as amended) do not contain adequate 
or appropriate safety standards for the Boeing Model 767-300 series 
airplanes because of a novel or unusual design feature, special 
conditions are prescribed under the provisions of 14 CFR 21.16.
    In addition to the applicable airworthiness regulations and special 
conditions, the Boeing Model 767-300 must comply with the fuel vent and 
exhaust emission requirements of 14 CFR part 34 and the noise 
certification requirements of 14 CFR part 36.
    Special conditions, as appropriate, are issued in accordance with 
14 CFR 11.49 after public notice, as required by 14 CFR 11.28 and 
11.29(b), and become part of the type certification basis in accordance 
with 14 CFR 21.101(b)(2).
    Special conditions are initially applicable to the model for which 
they are issued. Should the applicant apply for a supplemental type 
certificate to modify any other model included on the same type 
certificate to incorporate the same novel or unusual design feature, 
the special conditions would also apply to the other model under the 
provisions of 21.101(a)(1).

Novel or Unusual Design Features

    The Model 767-300 series airplanes will incorporate the following 
novel or unusual design features: Am-Safe, Inc. is proposing to install 
an inflatable lapbelt on certain seats of Boeing Model 767-300 series 
airplanes, in order to reduce the potential for head injury in the 
event of an accident. The inflatable lapbelt works similarly to a fixed 
mounted airbag, except that the airbag is integrated with the lap belt 
of the restraint system.
    The CFR states the performance criteria for head injury protection 
in objective terms. However, none of these criteria are adequate to 
address the specific issues raised concerning seats with inflatable 
lapbelts. The FAA has therefore determined that, in addition to the 
requirements of 14 CFR part 25, special conditions are needed to 
address requirements particular to installation of seats with 
inflatable lapbelts.
    Accordingly, in addition to the passenger injury criteria specified 
in 14 CFR 25.785, these special conditions are adopted for the Boeing 
Model 767-300 series airplanes equipped with inflatable lapbelts. Other 
conditions may be developed, as needed, based on further FAA review and 
discussions with the manufacturer and civil aviation authorities.

Discussion

    From the standpoint of a passenger safety system, the airbag is 
unique in that it is both an active and entirely autonomous device. 
While the automotive industry has good experience with airbags, the 
conditions of use and reliance on the airbag as the sole means of 
injury protection are quite different. In automobile installations, the 
airbag is a supplemental system and works in conjunction with an upper 
torso restraint. In addition, the crash event is more definable and of 
typically shorter duration, which can simplify the activation logic. 
The airplane-operating environment is also quite different from 
automobiles and includes the potential for greater wear and tear, and 
unanticipated abuse conditions (due to galley loading, passenger 
baggage, etc.);

[[Page 51427]]

airplanes also operate where exposure to high intensity electromagnetic 
fields could affect the activation system.
    The following special conditions can be characterized as addressing 
either the safety performance of the system, or the system's integrity 
against inadvertent activation. Because a crash requiring use of the 
airbags is a relatively rare event, and because the consequences of an 
inadvertent activation are potentially quite severe, these latter 
requirements are probably the more rigorous from a design standpoint.

Discussion of Comments

    Notice of proposed special conditions, Notice No. 25-99-03-SC, for 
the Boeing Model 767-300 series airplanes; equipped with inflatable 
lapbelts was published in the Federal Register on May 13, 1999 (64 FR 
2581). Eight commenters responded to the Notice.
    Six commenters addressed special condition #1, concerning the range 
of occupants and conditions of occupancy that must be considered when 
qualifying the inflatable lapbelt. One commenter felt that pregnant 
women should be added to the occupants considered. Other commenters 
stated that the range of occupant statures specified was not 
substantiated, and that there were existing accepted ranges that were 
applicable to this installation that should be used. Some commenters 
inferred from the wording of condition #1 that ``consideration'' of the 
scenarios specified meant that occupant protection must be demonstrated 
for those scenarios. Another commenter pointed out that occupant 
stature was very important to the performance of the inflatable 
lapbelt, considering that the occupant's lap and lower limbs were 
likely to provide the bearing surface for the airbag. A commenter also 
noted that, once deployed, the airbag will absorb energy based upon its 
size, pressure and vent area, and to require a ``consistent'' level of 
energy absorption for all occupant sizes is virtually impossible.
    After further consideration, the FAA has concluded that the 
established range of occupant stature, inclusive of the ninety-fifth 
percentile male is sufficient to address the performance of the 
inflatable lapbelt. Consideration of larger occupants, while desirable, 
is not specifically unique to this installation, and therefore should 
not be made an additional criterion by special condition. The FAA does, 
however, continue to maintain that small children should be 
accommodated by the inflatable lapbelt, and should not be subject to 
any hazards associated with its deployment. There were no adverse 
comments to this aspect of the proposal.
    With respect to consideration of occupancy conditions given in 
conditions #1.a., b., and c., it was not the FAA's intent that the 
lapbelt be shown to accommodate all of these conditions. The intent of 
the condition was to cause each case to be addressed, and either 
demonstrated to be acceptable, or prohibited from occurring by 
operational limitations. Thus, if the inflatable lapbelt cannot 
accommodate a child restraint device, it would be acceptable to 
prohibit use of child restraint devices in seats so equipped. The same 
is true for the other conditions.
    With respect to the requirement that the inflatable lapbelt provide 
a ``consistent level of energy absorption'' the FAA agrees that the 
amount of energy absorbed is dependent on the amount of energy input, 
and that will vary according to occupant size. The use of the word 
consistent may be confusing in this case. The intent of the requirement 
is to ensure that the range of occupants under consideration is 
presented with a consistent approach to injury protection, such that 
all occupants are afforded protection by the same mechanisms. This 
requirement has the effect of both establishing a consistent approach 
to injury protection for the range of occupants, as well as permitting 
demonstration with the fiftieth percentile anthropomorphic test dummy 
(ATD) to show compliance for the extremes of the ranges.
    With respect to pregnant women, the FAA agrees that there should be 
some instruction provided regarding use of the seat with an inflatable 
lapbelt. This requirement is added as condition #1.d., which would 
enable the applicant to either demonstrate or restrict such occupancy.
    It is clear that the performance of the inflatable lapbelt will 
depend to a large extent on the bearing surface, whether it is the 
person occupying the seat themselves or it is the airplane interior 
structure. The FAA considers this to be part of the basic qualification 
of the system, and however the system performs, it must be shown to do 
so reliably and consistently for the range of occupants.
    Two commenters addressed condition #2 regarding the number of 
seated occupants to be considered. Both commenters stated that the 
wording of the condition implies that the buckles must have switches, 
and that a buckle is required for firing. Both commenters request 
clarification of the term ``adequate protection''. One commenter 
suggested alternative wording.
    In this case, the design incorporates switches in the buckle 
assembly, and so the special condition addresses that design. Other 
designs might be addressed differently, but the main issue is to 
consider the effect on occupants of a partially occupied seat assembly, 
if all of the airbags activate. In that instance, the inflatable 
lapbelt should still perform its safety function for each occupant, and 
there should be no hazard (either as a result of the deployment, or to 
egress) from inflatable lapbelts that might activate in unoccupied seat 
places. In order to account for possible design changes, the wording is 
adjusted slightly to remove the word ``buckled'' and simply state that 
the unoccupied seats may have ``active'' inflatable lapbelts.
    One commenter stated that condition #3 is subjective, and the 
stiffness of the belt should suffice to satisfy the requirement. 
Another commenter pointed out that a person could properly fasten the 
belt, and then twist the whole assembly so as to invert the buckle with 
respect to its proper position. The same commenter also noted that a 
loosely fastened belt should be considered.
    The intent of this requirement is to make improper use of the belt 
unlikely. While there may be some subjectivity in this determination, 
there are practical design measures that will effectively eliminate the 
chance that a person would inadvertently misuse the lapbelt. The 
situation where a person deliberately inverts the buckle is different, 
and the intent of the special condition was not to account for such 
situations. Nonetheless, the measures taken to address inadvertent 
misuse will also likely be effective in preventing or minimizing 
deliberate misuse. With respect to a loosely fastened belt, this is 
something that no doubt occurs on standard seatbelts and reduces their 
effectiveness. The FAA agrees that a loosely fastened belt should not 
result in any greater risk to the occupant than on a standard belt, but 
cannot require that the inflatable belt be demonstrated to perform as 
well in this condition as when it is properly fastened. This provision 
is added to condition #5, which addresses occupants in the brace 
position.
    Four commenters felt that the requirement of condition #4 was 
vague, and that ``wear and tear'' needed further definition. Some 
commenters felt that this requirement could be linked to inspection and 
instructions for continued airworthiness, which are required anyway. 
One commenter indicated that the condition is directed at pyrotechnic 
devices, which may not be typical.
    The FAA agrees that the term ``wear and tear'' is not particularly 
specific,

[[Page 51428]]

and this was intentional. Depending on where certain components of the 
system are installed, their susceptibility to in-service wear and tear 
will vary. It is the intent of this requirement that the inflatable 
lapbelt will not deploy as a result of foreseeable in-service 
conditions, including interaction with passengers, if applicable, use 
of service carts, if applicable, and so on. There are regulatory 
requirements for instructions for continued airworthiness, which 
continue to apply and are not a substitute for these special 
conditions. The device in question is pyrotechnically activated and, 
therefore, this condition was written with that in mind. Other designs 
that might require a different condition, or might not require a 
similar consideration, are not the subject of this special condition. 
No change is made to the special condition.
    Four commenters felt that the requirement of condition #5 was 
impractical as stated, since no injury severity level was specified. 
One commenter pointed out that a bruise could be considered an injury 
under the current wording, and would therefore make the inflatable 
lapbelt unacceptable. Commenters point out that a person sitting in a 
fully compliant standard seat is likely to suffer some injuries as a 
result of an accident of the severity addressed by the regulations, and 
that the requirement should be that their ability to egress the 
airplane not be adversely affected.
    The FAA agrees that the proposed wording could have unintended 
consequences. The intent of the requirement is to prevent the 
introduction of injury mechanisms that did not exist previously, or 
would not be present on a seat that complied with the regulations 
directly. In this regard, injuries that would affect rapid egress are 
certainly of concern. However, there could be other injury mechanisms 
that might not have a direct impact on rapid egress, but could still be 
debilitating. In order to clarify the requirement, the wording is 
changed to require that the inflatable lapbelt not introduce injury 
mechanisms and that rapid egress not be affected.
    Three commenters addressed the issue of brace position. Comments 
concerned establishing what is an acceptable brace position and on what 
basis an injury assessment should be made.
    For the purposes of this special condition, the brace position is 
considered to be that shown on the operators' safety information card. 
The FAA does not expect that different approaches to the brace 
positions are feasible for seats with and without the inflatable 
lapbelt (for example considering the seated, upright position as the 
``brace'' position for these seats). It is recognized that the current 
approach to brace position does result in a different position for 
seats that are closely spaced, versus those that aren't. In both of 
those cases, however, the approach is to assume a position bending as 
far forward as possible. Considering the modifications made to 
condition #5, this requirement will be combined with that one as a 
consideration to be addressed when determining injury potential. (Note: 
The special conditions are renumbered due to the combining of Notice 
conditions #5 and #6).
    There was one comment regarding condition #6 (condition #7 of 
Notice), the need to demonstrate that inadvertent deployment that could 
cause injury to a sitting or standing person is improbable 
(10-5/flt-hour). The commenter felt that this requirement 
could be open-ended unless inadvertent deployment was shown to be 
extremely improbable (10-9/flt-hour). The FAA does not 
agree. Demonstration of reliability at the improbable level is 
sufficient to satisfy the objective of the requirement.
    Two commenters addressed the requirement that an inadvertent 
deployment that could cause a hazard to continued safe flight and 
landing be extremely improbable. Both commenters agree with the 
requirement, however, one commenter believes it is unnecessary, since 
the commenter feels the inflatable lapbelt cannot cause such a hazard. 
While the FAA agrees that the design as it is currently understood is 
unlikely to constitute a direct hazard to safe flight, this requirement 
is fundamental to the acceptability of such a system. Thus, while the 
system may, in practice, not constitute a hazard, the possibility 
cannot be ruled out, and criteria are needed in that event.
    Four commenters questioned the proposed requirement addressing 
impediment to rapid egress. One commenter stated that some ground rules 
are necessary to make an objective assessment. Another commenter 
questioned the origin of the 10 second standard proposed, and whether 
that standard applied equally to accidents that consisted of single and 
multiple impacts. One commenter stated that the deflated airbag should 
also be considered. Another commenter noted that the deflation of the 
airbag is dependent on vent size and the impact occuring to the bag 
itself. If there is no impact, the bag will vent naturally, and 
typically more slowly than if it were impacted.
    The requirement as written was intended to address both the 
inflated and deflated conditions, as well as a representative accident 
scenario, from initial impact until the airplane comes to rest. The 
reason that a specific time interval was chosen was in consideration of 
the fact that an evacuation cannot take place simultaneously with the 
accident. The 10 second interval was established based on FAA review of 
both test and accident data concerning the time from impact until an 
airplane comes to rest, coupled with the time needed to prepare exits 
and escape slides for evacuation. Therefore, 10 seconds after the 
device deploys, it should not impede rapid egress of occupants. This 
includes occupants of seats adjacent to deployed devices, as well as 
occupants of the seat in which the device deploys. No change is made to 
this provision.
    One commenter questioned the need to address lightning and high 
intensity radiated fields (HIRF), considering the potential hazard. The 
FAA regards this as a necessary requirement since the failure to 
address it potentially increases the hazards present. If the inflatable 
lapbelt were not protected from HIRF and lightning effects the 
potential for inadvertent deployment increases dramatically, and the 
associated risk would increase accordingly. Therefore, the requirement 
remains as written.
    One commenter noted that, in the preamble discussion regarding 
condition #10 (condition #11 of Notice), a transverse separation 
occurring at the location of the inflatable lapbelt is excluded from 
consideration. The commenter suggests that this provision be included 
in condition #10 (condition #11 of Notice) itself. This has been done.
    Two commenters believe that condition #11 (condition #12 of Notice) 
is too vague, and that no standards are provided to determine what 
constitutes a ``hazardous quantity'' of gas. One commenter questions 
whether the hazard extends to the effect on visibility from release of 
any gases.
    This requirement was left intentionally general, since there are so 
many different approaches to inflation systems and the gases used. 
Since the bag is vented to the cabin, it is assumed that occupants will 
be exposed to the gases used. To large extent, then, this requirement 
will dictate the gases that are used. The FAA considers it appropriate 
to allow the applicant to demonstrate that that the gases released do 
not pose a safety hazard, and there are several options for doing this. 
There was no intent to address visibility as part of this condition, 
although it theoretically could be an issue as part of

[[Page 51429]]

condition #8 (condition #9 of Notice). This isn't expected to be the 
case, however.
    Two commenters responded to the requirement that the inflatable 
lapbelt be protected from the effects of fire. Both commenters agree 
with the intent of the requirement. One commenter proposes alternative 
wording to clarify that the effects of the fire are applicable to the 
most critical component of the system, and the other commenter proposes 
that the standards currently used for chemical oxygen generators should 
be adequate.
    Again, this requirement was intentionally general, since the system 
design and installation will dictate the fire threat, as well as the 
consequences of the threat. For example, an installation that isolated 
any pyrotechnic devices or pressure vessels from the occupants might 
not be as critical as one where those items are inside the passenger 
cabin. In terms of the standards to be used, there are existing 
standards for pressure vessels, gas generators and other components 
that could be applied to this device/installation. The FAA expects the 
applicant to propose standards that are applicable in this case.
    There was one comment regarding the provisions of condition #13 
(condition #14 of Notice). This condition requires that there be means 
to enable a crewmember to determine whether the system is operable, or 
that the system has been shown to be reliable over a specified 
inspection interval. The commenter notes that readiness indicators can 
add complexity to the system and actually reduce reliability. The 
commenter clarifies the understanding that an inspection interval based 
on reliability data is an acceptable method of compliance.
    As noted above, the special condition allows more than one method 
of verifying system integrity. Either of the approaches is acceptable, 
but the FAA considers it necessary to minimize the possibility that the 
system could experience an undetected failure.
    One commenter had several general comments regarding the wisdom of 
incorporating such a device on an airplane, considering the potential 
for inadvertent deployments or misuse, versus the probability of having 
an accident in the first place. The commenter contends that the risk of 
the former outweighs the risk of the latter. The FAA agrees that this 
could be an issue, considering the very low accident rate, however, 
this is one of the main issues of the special conditions. The special 
conditions are written to prevent the inadvertent deployments or show 
that such deployments are not a hazard. If the special conditions are 
met, the FAA considers that this is not an issue.

Applicability

    As discussed above, these special conditions are applicable to the 
Model 767-300 series airplanes. Should Am-Safe, Inc. apply at a later 
date for a supplemental type certificate to modify any other model 
included on Type Certificate No. A1NM to incorporate the same novel or 
unusual design feature, the special conditions would apply to that 
model as well under the provisions of 21.101(a)(1).

Conclusion

    This action affects only certain novel or unusual design features 
on the Boeing Model 767-300 series airplanes. It is not a rule of 
general applicability, and it affects only the applicant who applied to 
the FAA for approval of these features on the airplane.

List of Subjects in 14 CFR Part 25

    Air transportation, Aircraft, Aviation safety, Safety, Reporting 
and recordkeeping requirements.

    The authority citation for these special conditions is as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704.

The Special Conditions

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the following special conditions are issued as part of 
the type certification basis for the Boeing Model 767-300 series 
airplanes modified by Am-Safe, Inc. by installing inflatable lapbelts.
    1. Seats With Inflatable Lapbelts. It must be shown that the 
inflatable lapbelt will deploy and provide protection under crash 
conditions where it is necessary to prevent serious head injury. The 
means of protection must take into consideration a range of stature 
from a two-year-old child to a ninety-fifth percentile male. The 
inflatable lapbelt must provide a consistent approach to energy 
absorption throughout that range. In addition, the following situations 
must be considered:
    a. The seat occupant is holding an infant.
    b. The seat occupant is a child in a child restraint device.
    c. The seat occupant is a child not using a child restraint device.
    d. The seat occupant is a pregnant woman.
    2. The inflatable lapbelt must provide adequate protection for each 
occupant regardless of the number of occupants of the seat assembly, 
considering that unoccupied seats may have active seatbelts.
    3. The design must prevent the inflatable lapbelt from being either 
incorrectly buckled or incorrectly installed such that the airbag would 
not properly deploy. Alternatively, it must be shown that such 
deployment is not hazardous to the occupant, and will provide the 
required head injury protection.
    4. It must be shown that the inflatable lapbelt system is not 
susceptible to inadvertent deployment as a result of wear and tear, or 
inertial loads resulting from in-flight or ground maneuvers (including 
gusts and hard landings), likely to be experienced in service.
    5. Deployment of the inflatable lapbelt must not introduce injury 
mechanisms to the seated occupant, or result in injuries that could 
impede rapid egress. This assessment should include an occupant who is 
in the brace position when it deploys and occupants whose belt is 
loosely fastened.
    6. It must be shown that an inadvertent deployment, that could 
cause injury to a standing or sitting person, is improbable.
    7. It must be shown that inadvertent deployment of the inflatable 
lapbelt, during the most critical part of the flight, will either not 
cause a hazard to the airplane or is extremely improbable.
    8. It must be shown that the inflatable lapbelt will not impede 
rapid egress of occupants 10 seconds after its deployment.
    9. The system must be protected from lightning and HIRF. The 
threats specified in Special Condition No. 25-ANM-18 are incorporated 
by reference for the purpose of measuring lightning and HIRF 
protection. For the purposes of complying with HIRF requirements, the 
inflatable lapbelt system is considered a ``critical system'' if its 
deployment could have a hazardous effect on the airplane; otherwise it 
is considered an ``essential'' system.
    10. The inflatable lapbelt must function properly after loss of 
normal aircraft electrical power, and after a transverse separation of 
the fuselage at the most critical location. A separation at the 
location of the lapbelt does not have to be considered.
    11. It must be shown that the inflatable lapbelt will not release 
hazardous quantities of gas or particulate matter into the cabin.
    12. The inflatable lapbelt installation must be protected from the 
effects of fire such that no hazard to occupants will result.
    13. There must be a means for a crewmember to verify the integrity 
of

[[Page 51430]]

the inflatable lapbelt activation system prior to each flight or it 
must be demonstrated to reliably operate between inspection intervals.

    Issued in Renton, Washington, on September 15, 1999.
Vi L. Lipski,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service, ANM-100.
[FR Doc. 99-24792 Filed 9-22-99; 8:45 am]
BILLING CODE 4910-13-P