Federal Register / Vol. 65, No. 197 / Wednesday, October 11, 2000 / Rules and Regulations 60343

List of Subjects in 13 CFR Part 121

Administrative practice and

procedure, Government procurement,

Government property, Grant programs—

business, Loan programs—business,

Report and record keeping requirement,

Small business.

For reasons stated in the preamble,

SBA is amending 13 CFR part 121 as

follows:

PART 121—SMALL BUSINESS SIZE

REGULATIONS

1. The authority citation for part 121

continues to read as follows:

Authority: 15 U.S.C. 632(a), 634(b)(6),

637(a), 644(c), and 662(5); and Sec. 304, Pub.

L. 103–403,108 Stat. 4175, 4188.

2. In § 121.201, amend the table

‘‘Small Business Size Standards by

NAICS Industry’’ as follows:

a. Under the heading Sector 21—

Mining, a new heading is added reading

‘‘Subsector 213—Support Activities for

Mining’’ below the entry for 212399, All

Other Nonmetallic Mineral Mining and

above the entry for 213111, Drilling Oil

and Gas Wells;

b. Under the heading Sectors 48–49—

Transportation, Subsector 488—Support

Activities for Transportation, revise the

entry for 488510.

The revisions read as follows:

§ 121.201 What size standards has SBA

identified by North American Industry

Classification System codes?

* * * * *

SIZE STANDARD BY NAICS INDUSTRY

NAICS codes Description

(N.E.C. = Not Elsewhere Classified)

Size standards in number of employees or million of dollars

*******

Sector 21—Mining

*******

212399 ............................ All Other Nonmetallic Mineral Mining ..................................................................................... .............500

Subsector 213—Support Activities for Mining

*******

Sector 48–49—Transportation

*******

Subsector 488—Support Activities for Transportation

*******

488510 ............................ Freight Transportation Arrangement ...................................................................................... ....................10 $5.0

EXCEPT .................. Non-Vessel Owning Common Carriers and Household Goods Forwarders .......................... ......................$18.5

*******

c. Revise footnote 10 to read as

follows:

Footnotes:

* * * * *

10. NAICS codes 488510 (part), 531210,

541810, 561510 and 561920—As measured

by total revenues, but excluding funds

received in trust for an unaffiliated third

party, such as bookings or sales subject to

commissions. The commissions received are

included as revenue.

* * * * *

Dated: October 3, 2000.

Gary Jackson,

Assistant Administrator for Size Standards.

[FR Doc. 00–25991 Filed 10–10–00; 8:45 am]

BILLING CODE 8025–01–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM176; Special Conditions No.

25–165–SC]

Special Conditions: British Aerospace

Jetstream 4101 Series Airplanes; Seats

with Inflatable Lapbelts

AGENCY: Federal Aviation

Administration (FAA), DOT.

ACTION: Final special conditions; request

for comments.

SUMMARY: These special conditions are

issued for British Aerospace (BAE)

Systems Jetstream Model 4101 series

airplanes, modified by BAE Systems to

include 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.

DATES: The effective date of these

special conditions is September 28,

2000. Comments must be received on or

before November 13, 2000.

ADDRESSES: Submit comments in

duplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–114,

60344 Federal Register / Vol. 65, No. 197 / Wednesday, October 11, 2000 / Rules and Regulations

Attention: Rules Docket No. NM176,

1601 Lind Avenue, SW., Renton,

Washington 98055–4056. Comments

may be inspected at this location

between 7:30 a.m. and 4 p.m., Monday

through Friday, except Federal holidays.

Comments may be submitted via fax to

(425) 227–1232. Comments may also be

sent via the Internet using the following

address: 9-anm-nprmcomment@faa.gov.

Comments sent via fax or the Internet

must contain ‘‘Docket No. NM176’’ in

the subject line and need not be

submitted in triplicate. Comments sent

via the Internet as attached electronic

files must be formatted in Microsoft

Word 97 for Windows or ASCII text.

FOR FURTHER INFORMATION CONTACT:

Todd Thompson, International Branch,

ANM–116, Transport Airplane

Directorate, Aircraft Certification

Service, FAA, 1601 Lind Avenue SW.,

Renton, Washington, 98055–4056;

telephone (206) 227–1175; facsimile

(425) 227–1149.

SUPPLEMENTARY INFORMATION: The FAA

has determined that notice and

opportunity for prior public comment

hereon are impracticable because these

procedures would significantly delay

issuance of the approval design and

thus delivery of the affected airplanes.

Comments Invited

Interested persons are invited to

submit such written data, views, or

arguments as they may desire.

Communications should identify the

Rules Docket number identified above

and be submitted in duplicate to the

address specified above. All

communications received on or before

the closing date for comments specified

above will be considered. The special

conditions may be changed in light of

the comments received.

All comments received will be

available in the Rules Docket for

examination by interested persons, both

before and after the closing date for

comments. A report summarizing each

substantive public contact with FAA

personnel concerning this rulemaking

will be filed in the Rules Docket.

Commenters wishing the FAA to

acknowledge receipt of their comments

submitted in response to this request

must submit a self-addressed, stamped

postcard on which the following

statement is made: ‘‘Comments to

Docket Number NM176.’’ The postcard

will be date stamped and returned to the

commenter.

Background

On April 28, 1999, British Aerospace

Systems applied for a change to Type

Certificate No. A41NM for the

installation of an Amsafe inflatable

airbag-seatbelt for the front row

passenger seats in the British Aerospace

System Jetstream 4101 series airplane.

The Model 4101 series airplane is a

straight-wing, conventional-tail, twinengine, turboprop-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 part 25, a new

standard that quantifies required head

injury protection was created.

Section 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 1000 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. In addition HIC

is the only available quantifiable

measure of head injury protection.

Therefore, the FAA will require that a

HIC of less than 1000 be demonstrated

for occupants of seats incorporating the

inflatable lapbelt.

Because § 25.562, § 25.785, 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.

BAE Systems 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

Federal Register / Vol. 65, No. 197 / Wednesday, October 11, 2000 / Rules and Regulations 60345

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–48

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

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 active.

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 by

deploying 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.

Similarly, if a pregnant woman occupies

the seat, the installation needs to

address such usage, 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.

Finally, it should be noted that the

special conditions are certification

requirements applied to the inflatable

lapbelt system as installed. The special

conditions are not an installation

approval. Therefore, while the special

conditions relate to each such system

installed, the overall installation

approval is a separate finding and must

consider the combined effects of all

such systems installed.

Type Certification Basis

Under the provisions of § 21.101, BAE

Systems must show that the Model 4101

series airplanes, as changed, continue to

meet the applicable provisions of the

regulations incorporated by reference in

Type Certificate No. A41NM 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. A41NM are as follows:

Amendments 25–1 through 25–66 with

exceptions. The U.S. type certification

basis for the Model 4101 is established

in accordance with §§ 21.29 and 21.17,

and the type certification application

date to the United Kingdom Civil

Aviation Authority. The U.S. type

certification basis is listed in Type

Certificate Data Sheet No. A41NM.

If the Administrator finds that the

applicable airworthiness regulations

(i.e., part 25 as amended) do not contain

adequate or appropriate safety standards

for the Model 4101 series airplanes

because of a novel or unusual design

feature, special conditions are

prescribed under the provisions of

§ 21.16.

In addition to the applicable

airworthiness regulations and special

conditions, the Model 4101 must

comply with the fuel vent and exhaust

emission requirements of part 34 and

the noise certification requirements of

part 36.

Special conditions, as appropriate, are

issued in accordance with § 11.49 after

public notice, as required by §§ 11.28

and 11.29(b), and become part of the

type certification basis in accordance

with § 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 4101 series airplanes will

incorporate the following novel or

unusual design features. BAE Systems

plans to install an Amsafe Inc, inflatable

lapbelt on the front row passenger seats

60346 Federal Register / Vol. 65, No. 197 / Wednesday, October 11, 2000 / Rules and Regulations

of the Model 4101 series airplanes, in

order to reduce the potential for head

injury in the event of an accident. The

inflatable lapbelt works similarly to an

automotive 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 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

§ 25.785, these special conditions are

adopted for the BAE Model 4101 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.);

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.

Applicability

As discussed above, these special

conditions are applicable to the Model

4101 series airplanes. Should BAE

Systems apply at a later date for

modification of any other model

included on Type Certificate No.

A41NM 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 BAE

Systems Model 4101 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.

Immediate Adoption of Special

Conditions

The substance of these special

conditions has been subject to the notice

and comment period in two prior

instances and has been derived without

substantive change from those

previously issued. It is unlikely that

prior public comment would result in a

significant change from the substance

contained herein. For this reason, and

because a delay would significantly

affect the certification of the airplane,

which is imminent, the FAA has

determined that prior public notice and

comment are unnecessary and

impracticable, and good cause exists for

adopting these special conditions upon

issuance. The FAA is requesting

comments to allow interested persons to

submit views that may not have been

submitted in response to the prior

opportunities for comment described

above.

List of Subjects in 14 CFR Part 25

Aircraft, Aviation safety, Reporting

and recordkeeping requirements.

Authority Citation

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 British Aerospace

(BAE) Systems Model 4101 series

airplanes equipped with Amsafe

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 an occupant

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, considering the

requirements of Special Conditions No.

25–NM–45, issued July 9, 1991, and

Special Conditions No. 25–NM–45A,

issued November 8, 1994, concerning

cabin aisle width.

9. The system must be protected from

lightning and high-intensity radiated

fields (HIRF). The threats specified in

Special Condition No. 25–ANM–48 are

incorporated by reference for the

purpose of measuring lightning and

HIRF protection. For the purposes of

Federal Register / Vol. 65, No. 197 / Wednesday, October 11, 2000 / Rules and Regulations 60347

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

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 28, 2000.

Dorenda D. Baker,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 00–26016 Filed 10–10–00; 8:45 am]

BILLING CODE 4910–13–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000–NM–286–AD; Amendment

39–11927; AD 2000–20–16]

RIN 2120–AA64

Airworthiness Directives; Boeing

Model 757–200 Series Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Final rule; request for

comments.

SUMMARY: This amendment adopts a

new airworthiness directive (AD) that is

applicable to certain Boeing Model 757–

200 series airplanes. This action

requires repetitive inspections of the

cargo loader system in the forward and

aft cargo compartments to detect

discrepancies, and corrective actions, if

necessary. This action is necessary to

detect and correct such discrepancies,

which could result in reduced structural

integrity of the fuselage and consequent

cabin depressurization.

DATES: Effective October 26, 2000.

The incorporation by reference of

certain publications listed in the

regulations is approved by the Director

of the Federal Register as of October 26,

2000.

Comments for inclusion in the Rules

Docket must be received on or before

December 11, 2000.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–114,

Attention: Rules Docket No. 2000–NM–

286–AD, 1601 Lind Avenue, SW.,

Renton, Washington 98055–4056.

Comments may be inspected at this

location between 9:00 a.m. and 3:00

p.m., Monday through Friday, except

Federal holidays. Comments may be

submitted via fax to (425) 227–1232.

Comments may also be sent via the

Internet using the following address: 9-

anm-iarcomment@faa.gov. Comments

sent via fax or the Internet must contain

‘‘Docket No. 2000–NM–286–AD’’ in the

subject line and need not be submitted

in triplicate. Comments sent via the

Internet as attached electronic files must

be formatted in Microsoft Word 97 for

Windows or ASCII text.

The service information referenced in

this AD may be obtained from Boeing

Commercial Airplane Group, P.O. Box

3707, Seattle, Washington 98124–2207.

This information may be examined at

the FAA, Transport Airplane

Directorate, 1601 Lind Avenue, SW.,

Renton, Washington; or at the Office of

the Federal Register, 800 North Capitol

Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Dennis Stremick, Aerospace Engineer,

Airframe Branch, ANM–120S, FAA,

Seattle Aircraft Certification Office,

1601 Lind Avenue, SW., Renton,

Washington 98055–4056; telephone

(425) 227–2776; fax (425) 227–1181.

SUPPLEMENTARY INFORMATION: The FAA

has received reports indicating that, on

certain Boeing Model 757–200 series

airplanes, damage has been detected to

the fiberglass pan and fuselage frames

located in the forward and aft cargo

compartments. This damage has been

attributed to incorrect operation of the

cargo loader system and subsequent

wear damage completely through the

fiberglass pan, and in some cases, to the

adjacent fuselage frames. This

condition, if not corrected, could result

in reduced structural integrity of the

airplane fuselage and consequent cabin

depressurization.

Explanation of Relevant Service

Information

The FAA has reviewed and approved

Boeing Alert Service Bulletin 757–

25A0233, dated August 10, 2000, which

describes procedures for repetitive

inspections of the cargo loader system

in the forward and aft cargo

compartments to detect discrepancies

(i.e., improper operation, wear damage

of the fiberglass pan and fuselage

frames), and corrective actions, if

necessary.

The corrective actions include

procedures for repair of the cargo loader

system if incorrectly installed or

deactivation of the system if the

fiberglass pan is worn to the extent that

fibers are exposed; follow-on inspection

of the fuselage frames if there is a hole

worn through the fiberglass pan

anywhere within the two-inches

forward or aft of any frame location;

repair or replacement of the damaged

pan; and repair of the fuselage frames if

damaged and damage is within the

limits specified in the structural repair

manual, as described in the alert service

bulletin. Following accomplishment of

the corrective actions, the alert service

bulletin recommends testing the cargo

loader system for proper operation. The

alert service bulletin also contains

instructions to contact the manufacturer

for reactivation of the cargo loader

system and disposition of certain

inspection and repair procedures.

Explanation of the Requirements of the

Rule

Since an unsafe condition has been

identified that is likely to exist or

develop on other products of this same

type design, this AD would require

accomplishment of the actions specified

in the alert service bulletin described

previously, except as discussed below.

Differences Between Alert Service

Bulletin and This AD

Operators should note that, although

the alert service bulletin permits

reactivation of the cargo loader system

after contacting the manufacturer for

disposition of inspection and repair

procedures, this AD requires

reactivation of the system and

disposition of the inspection and repair

procedures be accomplished in

accordance with a method approved by

the FAA.

Although the alert service bulletin

specifies accomplishment of

inspections, this AD refers to those

inspections as detailed visual

inspections. The FAA finds that

‘‘detailed visual inspection’’ is the

appropriate terminology for the

inspections described in the service

bulletin. Additionally, a definition of a

detailed visual inspection is included in

Note 2 of this proposed AD.

The alert service bulletin also

specifies repetitive inspections at

intervals not to exceed 300 flight cycles