7340 Federal Register / Vol. 62, No. 33 / Wednesday, February 19, 1997 / Rules and Regulations

The FAA’s Determination

After careful review of all available

information related to the subject

presented above, the FAA has

determined that air safety and the

public interest require the adoption of

the rule as proposed except for minor

editorial corrections. The FAA has

determined that these minor corrections

will not change the meaning of the AD

and will not add any additional burden

upon the public than was already

proposed.

Compliance Time of This AD

The compliance time for this AD is

presented in calendar time instead of

hours time-in-service. The fuel filler cap

may not seal properly regardless of

whether the airplane is in operation. For

this reason, the FAA has determined

that a calendar time for compliance is

the most desirable.

Cost Impact

The FAA estimates that 14 airplanes

in the U.S. registry will be affected by

this AD, that it will take approximately

3 workhours (average: 4 workhours for

seven airplanes and 2 workhours for

seven airplanes) per airplane to

accomplish the required action, and that

the average labor rate is approximately

$60 an hour. Based on these figures, the

total cost impact of the AD on U.S.

operators is estimated to be $2,520.

The above figure is based on the

presumption that no owner/operator of

the affected airplanes has accomplished

the required vent check valve assembly

removal. The FAA is aware that seven

of the affected airplanes are already in

compliance with this AD. With this

information in mind, the cost impact

upon U.S. operators/owners is reduced

by $1,260 from $2,520 to$1,260.

Regulatory Impact

The regulations adopted herein will

not have substantial direct effects on the

States, on the relationship between the

national government and the States, or

on the distribution of power and

responsibilities among the various

levels of government. Therefore, in

accordance with Executive Order 12612,

it is determined that this final rule does

not have sufficient federalism

implications to warrant the preparation

of a Federalism Assessment.

For the reasons discussed above, I

certify that this action (1) is not a

‘‘significant regulatory action’’ under

Executive Order 12866; (2) is not

a’’significant rule’’ under DOT

Regulatory Policies and Procedures (44

FR 11034, February 26, 1979); and (3)

will not have a significant economic

impact, positive or negative, on a

substantial number of small entities

under the criteria of the Regulatory

Flexibility Act. A copy of the final

evaluation prepared for this action is

contained in the Rules Docket. A copy

of it may be obtained by contacting the

Rules Docket at the location provided

under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation

safety, Incorporation by reference,

Safety.

Adoption of the Amendment

Accordingly, pursuant to the

authority delegated to me by the

Administrator, the Federal Aviation

Administration amends part 39 of the

Federal Aviation Regulations (14 CFR

part 39) as follows:

PART 39—AIRWORTHINESS

DIRECTIVES

1. The authority citation for part 39

continues to read as follows:

Authority: 49 USC 106(g), 40113, 44701.

§ 39.13 [Amended]

2. Section 39.13 is amended by

adding a new airworthiness directive

(AD) to read as follows:

97–04–13 Mitsubishi Heavy Industries,

Ltd.: Amendment 39–9938; Docket No.

96–CE–45–AD.

Applicability: Models MU–2B, MU–2B–10,

MU–2B–15, MU–2B–20, and MU–2B–30

airplanes (serial numbers 004 through 035,

037, 038, 101 through 230, 502 through 525,

and 527 through 547), certificated in any

category.

Note 1: This AD applies to each airplane

identified in the preceding applicability

provision, regardless of whether it has been

modified, altered, or repaired in the area

subject to the requirements of this AD. For

airplanes that have been modified, altered, or

repaired so that the performance of the

requirements of this AD is affected, the

owner/operator must request approval for an

alternative method of compliance in

accordance with paragraph (c) of this AD.

The request should include an assessment of

the effect of the modification, alteration, or

repair on the unsafe condition addressed by

this AD; and, if the unsafe condition has not

been eliminated, the request should include

specific proposed actions to address it.

Compliance: Required within the next 60

calendar days after the effective date of this

AD, unless already accomplished.

To prevent the inability of both engines to

utilize the entire fuel supply because of the

outboard fuel not transferring to the center

tank, which could result in an uncommanded

engine shutdown, accomplish the following:

(a) Remove the vent check valve assembly

in accordance with the instructions in

Mitsubishi MU–2 Service Bulletin No. 130A,

dated July 19, 1971.

(b) Special flight permits may be issued in

accordance with sections 21.197 and 21.199

of the Federal Aviation Regulations (14 CFR

21.197 and 21.199) to operate the airplane to

a location where the requirements of this AD

can be accomplished.

(c) An alternative method of compliance or

adjustment of the compliance time that

provides an equivalent level of safety may be

approved by the Manager, FAA, Los Angeles

Aircraft Certification Office (ACO), 3960

Paramount Boulevard, Lakewood, California

90712. The request shall be forwarded

through an appropriate FAA Maintenance

Inspector, who may add comments and then

send it to the Manager, Los Angeles ACO.

Note 2: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Los Angeles ACO.

(d) The removal required by this AD shall

be done in accordance with Mitsubishi MU–

2 Service Bulletin No. 130A, dated July 19,

1971. This incorporation by reference was

approved by the Director of the Federal

Register in accordance with 5 U.S.C. 552(a)

and 1 CFR part 51. Copies may be obtained

from Mitsubishi Heavy Industries, Ltd.,

Nagoya Aerospace Systems, 10, Oyecho,

Minato-Ku, Nagoya, Japan . Copies may be

inspected at the FAA, Central Region, Office

of the Assistant Chief Counsel, Room 1558,

601 E. 12th Street, Kansas City, Missouri, or

at the Office of the Federal Register, 800

North Capitol Street, NW., suite 700,

Washington, DC.

(e) This amendment (39–9938) becomes

effective on April 16, 1997. Issued in Kansas

City, Missouri, on February 11, 1997.

Henry A. Armstrong,

Acting Manager, Small Airplane Directorate,

Aircraft Certification Service.

[FR Doc. 97–3960 Filed 2–18–97; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 39

[Docket No. 96–NM–234–AD; Amendment

39–9929; AD 97–04–05]

RIN 2120–AA64

Airworthiness Directives; Jetstream

Model 4101 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 Jetstream Model

4101 airplanes. This action requires a

one-time inspection of the airplane

records to determine the modification

status of the elevator trim servo, and, if

necessary, inspections to determine the

serial number of the servo, and

repetitive inspections for looseness or

movement of the motor housing of the

servo. This action also requires

replacement of certain elevator trim

servos with a serviceable assembly. This
Federal Register / Vol. 62, No. 33 / Wednesday, February 19, 1997 / Rules and Regulations 7341

amendment is prompted by reports of

the motor housing separating from the

elevator trim servo and the consequent

release of certain component parts, due

to inadequate locking of screws that

were installed during assembly of the

servos. The actions specified in this AD

are intended to prevent the motor

housing of the elevator trim servo from

separating and releasing component

parts that could lodge in and jam the

elevator controls, and result in reduced

pitch control of the airplane.

DATES: Effective March 6, 1997.

The incorporation by reference of

certain publications listed in the

regulations is approved by the Director

of the Federal Register as of March 6,

1997.

Comments for inclusion in the Rules

Docket must be received on or before

April 21, 1997.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–103,

Attention: Rules Docket No. 96–NM–

234–AD, 1601 Lind Avenue, SW.,

Renton, Washington 98055–4056.

The service information referenced in

this AD may be obtained from Jetstream

Aircraft, Inc., P.O. Box 16029, Dulles

International Airport, Washington, DC

20041–6029. 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:

William Schroeder, Aerospace Engineer,

Standardization Branch, ANM–113,

FAA, Transport Airplane Directorate,

1601 Lind Avenue, SW., Renton,

Washington 98055–4056; telephone

(206) 227–2148; fax (206) 227–1149.

SUPPLEMENTARY INFORMATION: The Civil

Aviation Authority (CAA), which is the

airworthiness authority for the United

Kingdom, recently notified the FAA that

an unsafe condition may exist on certain

Jetstream Model 4101 airplanes The

CAA advises that it has received reports

indicating that separation of the motor

housing from the elevator trim servo

and consequent release of motor gearbox

components has occurred on a Jetstream

Model 4101 airplane. Investigation

revealed that certain elevator trim servo

units manufactured by Honeywell were

assembled using screws with inadequate

locking capability. Certain of these

screws fasten the servo motor inner gear

casing to the mounting flange and some

screws fasten the motor cap/sleeve to

the inner gear casing. The inadequate

locking of those screws caused the

separation of the motor housing from

the servo unit, and resulted in the

release of the motor gearbox

components. Those released

components could lodge in the elevator

controls and result in an elevator jam.

This condition, if not corrected, could

result in reduced control of the primary

pitch control of the airplane.

Explanation of Relevant Service

Information

Jetstream has issued Alert Service

Bulletin J41–A22–008, Revision 1, dated

November 21, 1996, which describes the

following procedures:

1. A one-time inspection of the

airplane records or a visual inspection

of the servo to determine if the elevator

trim servo is at Modification B standard

or greater.

2. For those airplanes on which the

elevator trim servo is not at

Modification B or greater, the alert

service bulletin describes procedures for

an inspection of the airplane records or

a visual inspection of the elevator trim

servo to determine the serial number of

the elevator trim servo, procedures for

repetitive visual and tactile inspections

of the motor housing of the elevator trim

servo to determine if the motor housing

is loose or moves, and repair of

replacement of the elevator trim servo

with a serviceable servo, if necessary.

Replacement of the servo with a

serviceable assembly would eliminate

the need for repetitive inspections of the

motor housing. The alert service

bulletin also describes procedures for

replacement of certain servos specified

in the alert service bulletin with a servo

at Modification B or later standard.

The CAA classified this service

bulletin as mandatory in order to assure

the continued airworthiness of these

airplanes in the United Kingdom.

FAA’s Conclusions

This airplane model is manufactured

in the United Kingdom and is type

certificated for operation in the United

States under the provisions of section

21.29 of the Federal Aviation

Regulations (14 CFR 21.29) and the

applicable bilateral airworthiness

agreement. Pursuant to this bilateral

airworthiness agreement, the CAA has

kept the FAA informed of the situation

described above. The FAA has

examined the findings of the CAA,

reviewed all available information, and

determined that AD action is necessary

for products of this type design that are

certificated for operation in the United

States.

Explanation of Requirements of Rule

Since an unsafe condition has been

identified that is likely to exist or

develop on other airplanes of the same

type design registered in the United

States, this AD is being issued to

prevent the motor housing of the

elevator trim servo from separating from

the servo assembly and releasing

component parts that could lodge in and

jam the elevator control, and result in

reduced pitch control of the airplane.

This AD requires the following:

1. A one-time inspection of the

airplane records or a visual inspection

of the servo to determine if the elevator

trim servo is at Modification B standard

or greater.

2. For those airplanes on which the

elevator trim servo is not at

Modification B standard or greater, an

inspection of the airplane records to

determine the serial number of the

elevator trim servo, repetitive visual and

tactile inspections of the motor housing

of the elevator trim servo to determine

if the motor housing is loose or moves,

and replacement of the elevator trim

servo with a serviceable servo, as

necessary.

3. Replacement of certain elevator

trim servos with a serviceable assembly.

The actions are required to be

accomplished in accordance with the

alert service bulletin described

previously.

Determine of Rule’s Effective Date

Since a situation exists that requires

the immediate adoption of this

regulation, it is found that notice and

opportunity for prior public comment

hereon are impracticable, and that good

cause exists for making this amendment

effective in less than 30 days.

Comments Invited

Although this action is in the form of

a final rule that involves requirements

affecting flight safety and, thus, was not

preceded by notice and opportunity for

public comment, comments are invited

on this rule. Interested persons are

invited to comment on this rule by

submitting such written data, views, or

arguments as they may desire.

Communications shall identify the

Rules Docket number and be submitted

in triplicate to the address specified

under the caption ADDRESSES. All

communications received on or before

the closing date for comments will be

considered, and this rule may be

amended in light of the comments

received. Factual information that

supports the commenter’s ideas and

suggestions is extremely helpful in

evaluating the effectiveness of the AD
7342 Federal Register / Vol. 62, No. 33 / Wednesday, February 19, 1997 / Rules and Regulations

action and determining whether

additional rulemaking action would be

needed.

Comments are specifically invited on

the overall regulatory, economic,

environmental, and energy aspects of

the rule that might suggest a need to

modify the rule. All comments

submitted will be available, both before

and after the closing date for comments,

in the Rules Docket for examination by

interested persons. A report that

summarizes each FAA-public contact

concerned with the substance of this AD

will be filed in the Rules Docket.

Commenters wishing the FAA to

acknowledge receipt of their comments

submitted in response to this rule must

submit a self-addressed, stamped

postcard on which the following

statement is made: ‘‘Comments to

Docket Number 96–NM–234–AD.’’ The

postcard will be date stamped and

returned to the commenter.

Regulatory Impact

The regulations adopted herein will

not have substantial direct effects on the

States, on the relationship between the

national government and the States, or

on the distribution of power and

responsibilities among the various

levels of government. Therefore, in

accordance with Executive Order 12612,

it is determined that this final rule does

not have sufficient federalism

implications to warrant the preparation

of a Federalism Assessment.

The FAA has determined that this

regulation is an emergency regulation

that must be issued immediately to

correct an unsafe condition in aircraft,

and that it is not a ‘‘significant

regulatory action’’ under Executive

Order 12866. It has been determined

further that this action involves an

emergency regulation under DOT

Regulatory Policies and Procedures (44

FR 11034, February 26, 1979). If it is

determined that this emergency

regulation otherwise would be

significant under DOT Regulatory

Policies and Procedures, a final

regulatory evaluation will be prepared

and placed in the Rules Docket. A copy

of it, if filed, may be obtained from the

Rules Docket at the location provided

under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation

safety, Incorporation by reference,

Safety.

Adoption of the Amendment

Accordingly, pursuant to the

authority delegated to me by the

Administrator, the Federal Aviation

Administration amends part 39 of the

Federal Aviation Regulations (14 CFR

part 39) as follows:

PART 39—AIRWORTHINESS

DIRECTIVES

1. The authority citation for part 39

continues to read as follows:

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

§ 39.13 [Amended]

2. Section 39.13 is amended by

adding the following new airworthiness

directive:

97–04–05 Jetstream: Amendment 39–9929.

Docket 96–NM–234–AD.

Applicability: Model 4101 airplanes having

serial numbers 41004 through 41090

inclusive, certificated in any category.

Note 1: This AD applies to each airplane

identified in the preceding applicability

provision, regardless of whether it has been

otherwise modified, altered, or repaired in

the area subject to the requirements of this

AD. For airplanes that have been modified,

altered, or repaired so that the performance

of the requirements of this AD is affected, the

owner/operator must request approval for an

alternative method of compliance in

accordance with paragraph (e) of this AD.

The request should include an assessment of

the effect of the modification, alteration, or

repair on the unsafe condition addressed by

this AD; and, if the unsafe condition has not

been eliminated, the request should include

specific proposed actions to address it.

Compliance: Required as indicated, unless

accomplished previously.

To prevent separation of the motor housing

of the elevator trim servo from the servo body

that would allow detachment of component

parts that could lodge in and jam the elevator

control, and result in reduced control of the

primary pitch of the airplane; accomplish the

following:

Note 2: Accomplishment of actions

required by this AD in accordance with

Jetstream Alert Service Bulletin J41–A22–

008, dated July 18, 1996, is not considered

acceptable for compliance with the

applicable action specified in this AD.

(a) Within 14 days after the effective date

of this AD: Perform either an inspection of

the airplane records or a visual inspection of

the elevator trim servo, to determine if the

elevator trim servo is at Modification B

standard or greater, in accordance with

Jetstream Alert Service Bulletin J41–A22–

008, Revision 1, dated November 21, 1996.

(b) If the inspection required by paragraph

(a) of this AD reveals that the elevator trim

servo is at Modification B standard or greater:

No further action is required by this AD.

(c) If the inspection required by paragraph

(a) of this AD reveals that the elevator trim

servo is not at Modification B standard or

greater: Prior to further flight, perform either

an inspection of the airplane records or a

visual inspection of the elevator trim servo,

to determine if the serial number of the

elevator trim servo is specified in paragraph

1.M.(4)(b) of Jetstream Alert Service Bulletin

J41–A22–008, Revision 1, dated November

21, 1996; and, regardless of the serial

number, perform both a visual inspection

and a tactile inspection of the motor housing

of the elevator trim servo to determine if the

motor housing is loose or moves, in

accordance with the alert service bulletin.

(1) If the motor housing does not move and

is not loose, and the elevator trim servo does

not have a serial number that is specified in

paragraph 1.M(4)(b) of the alert service

bulletin: No further action is required by this

AD.

(2) If the motor housing does not move and

is not loose, but the elevator trim servo has

a serial number that is specified in paragraph

1.M(4)(b) of the alert service bulletin: Repeat

the visual and tactile inspections of the

elevator trim servo thereafter at intervals not

to exceed 50 hours time-in-service, until the

requirements of paragraph (d) of this AD are

accomplished.

(3) If the motor housing moves or is loose,

regardless of serial number: Prior to further

flight, accomplish the requirements of either

paragraph (c)(3)(i) or (c)(3)(ii) of this AD:

(i) Secure the elevator trim servo and

deactivate the autopilot system, in

accordance with Part 3 of the

Accomplishment Instructions of the alert

service bulletin. Thereafter, repeat the visual

and tactile inspections at intervals not to

exceed 50 hours time-in-service, until the

requirements of paragraph (d) of this AD are

accomplished. Or

(ii) Replace the elevator trim servo with an

‘‘acceptable replacement’’ servo, as defined

by the ‘‘Note’’ in Paragraph 2.,

Accomplishment Instructions, of Jetstream

Alert Service Bulletin J41–A22–008, Revision

1, dated November 21, 1996. Accomplish the

replacement in accordance with Part 4 of the

Accomplishment Instructions of the alert

service bulletin. Accomplishment of this

replacement constitutes terminating action

for the repetitive inspections required by this

AD.

(d) For airplanes subject to paragraph (c)(2)

or (c)(3)(i) of this AD: Within 90 days after

the effective date of this AD, replace the

elevator trim servo with an ‘‘acceptable

replacement’’ servo, as defined by the ‘‘Note’’

in Paragraph 2., Accomplishment

Instructions, of Jetstream Alert Service

Bulletin J41–A22–008, Revision 1, dated

November 21, 1996. Accomplish the

replacement in accordance with Part 4 of the

Accomplishment Instructions of the alert

service bulletin. Accomplishment of this

replacement constitutes terminating action

for the repetitive inspections required by this

AD.

(e) An alternative method of compliance or

adjustment of the compliance time that

provides an acceptable level of safety may be

used if approved by the Manager,

Standardization Branch, ANM–113.

Operators shall submit their requests through

an appropriate FAA Principal Maintenance

Inspector, who may add comments and then

send it to the Manager, Standardization

Branch, ANM–113.

Note 3: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Standardization Branch,

ANM–113.

(f) Special flight permits may be issued in

accordance with sections 21.197 and 21.199
Federal Register / Vol. 62, No. 33 / Wednesday, February 19, 1997 / Rules and Regulations 7343

of the Federal Aviation Regulations (14 CFR

21.197 and 21.199) to operate the airplane to

a location where the requirements of this AD

can be accomplished.

(g) The actions shall be done in accordance

with Jetstream Alert Service Bulletin J41–

A22–008, Revision 1, dated November 21,

1996, which contains the specificed list of

effective pages:

Page No.

Revision level

shown on

page

Date shown

on page

1–10, 15 ..... 1 November

21,1996.

11–14, 16,

17.

(1) July 18,

1996.

1Original.

This incorporation by reference was

approved by the Director of the Federal

Register in accordance with 5 U.S.C 552(a)

and 1 CFR part 51. Copies may be obtained

from Jetstream Aircraft, Inc., P.O. Box 16029,

Dulles International Airport, Washington, DC

20041–6029. Copies may be inspected 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.

(h) This amendment becomes effective on

March 6, 1997.

Issued in Renton, Washington, on February

6, 1997.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 97–3535 Filed 2–18–97; 8:45 am]

BILLING CODE 4910–13–M

14 CFR Part 39

[Docket No. 96–ANE–42; Amendment 39–

9912; AD 97–03–06]

RIN 2120–AA64

Airworthiness Directives; Auxiliary

Power International Corporation Model

APS3200 Auxiliary Power Units

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Final rule; request for

comments.

SUMMARY: This amendment adopts a

new airworthiness directive (AD) that is

applicable to Auxiliary Power

International Corporation (APIC) Model

APS3200 Auxiliary Power Units (APUs).

This action requires replacement of the

existing Electronic Control Box (ECB),

incorporating its On Board Replaceable

Module (OBRM) programmed with

originally approved software version

2.0.2 or 3.2 with improved software

version 4.1, or replacement of the

existing OBRM of the ECB programmed

with version 2.0.2 or version 3.2 with a

new OBRM programmed with software

version 4.1. This amendment is

prompted by reports of continued fuel

flow to the APU after the APU was

commanded to shutdown, resulting in

internal APU fires. The actions specified

in this AD are intended to prevent

internal APU fires due to ECB

malfunction, which, if left unnoticed by

flight or ground crews, could result in

damage to the aircraft.

DATES: Effective March 6, 1997.

The incorporation by reference of

certain publications listed in the

regulations is approved by the Director

of the Federal Register as of March 6,

1997.

Comments for inclusion in the Rules

Docket must be received on or before

April 21, 1997.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), New England

Region, Office of the Assistant Chief

Counsel, Attention: Rules Docket No.

96-ANE–42, 12 New England Executive

Park, Burlington, MA 01803-5299.

The service information referenced in

this AD may be obtained from Auxiliary

Power International Corporation (APIC),

4450 Ruffin Rd., P.O. Box 85757, San

Diego, CA 92193-9090; telephone (619)

627–6501, fax (619) 627-6502. This

information may be examined at the

FAA, New England Region, Office of the

Assistant Chief Counsel, 12 New

England Executive Park, Burlington,

MA; or at the Office of the Federal

Register, 800 North Capitol Street, NW.,

suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Guy

Dalla Riva, Aerospace Engineer, Los

Angeles Aircraft Certification Office,

FAA, Transport Airplane Directorate,

3960 Paramount Blvd., Lakewood, CA

90712–4137; telephone (310) 627–5248;

fax (310) 627–5210.

SUPPLEMENTARY INFORMATION: The

Federal Aviation Administration (FAA)

has received reports of four Auxiliary

Power Units (APU) internal fires after

shutdown of Auxiliary Power

International Corporation (APIC) Model

APS3200 APUs. The investigations

revealed two possible causes of these

fires: first, in three of the events, a

software deficiency in the Electronic

Control Box (ECB) allowed the APU fuel

shut-off valve to remain open; second,

in one unconfirmed event, possible fuel

system contamination could have kept

the valve from closing completely. This

AD addresses the ECB software

deficiency only. It does not address

valve malfunction caused by fuel system

contamination.

These ECB malfunctions may result in

an internal fire within the APU, in the

APU plenum, air intake, and possibly in

the tail of the aircraft. This condition, if

not corrected, could result in an internal

APU fire due to ECB malfunction,

which, if left unnoticed by flight or

ground crews, could result in damage to

the aircraft.

The FAA has reviewed and approved

the technical contents of APIC Service

Bulletin (SB) No. 4500001–49–52, dated

October 1, 1996, that describes

procedures for replacement of the

existing On Board Replaceable Module

(OBRM) of the ECB incorporating the

software versions 2.0.2 or 3.2 with a

new OBRM programmed with software

version 4.1. This software also

commands closing of the aircraft APU

firewall fuel shut-off valve in addition

to the APU fuel shut-off valve during

APU shutdowns.

Since an unsafe condition has been

identified that is likely to exist or

develop on other APUs of the same type

design, this AD is being issued to

prevent an APU fire due to ECB

malfunction, which could result in

damage to the aircraft. This AD requires

replacement of the existing APU ECB

(incorporating the originally approved

software versions 2.0.2 or 3.2) with

improved software version. 4.1, or

installation of an OBRM programmed

with software version 4.1 in the ECB

prior to 30 days after the effective date

of this AD. This calendar end-date is

based on parts availability. The actions

are required to be accomplished in

accordance with the SB described

previously.

Since a situation exists that requires

the immediate adoption of this

regulation, it is found that notice and

opportunity for prior public comment

hereon are impracticable, and that good

cause exists for making this amendment

effective in less than 30 days.

Comments Invited

Although this action is in the form of

a final rule that involves requirements

affecting flight safety and, thus, was not

preceded by notice and an opportunity

for public comment, comments are

invited on this rule. Interested persons

are invited to comment on this rule by

submitting such written data, views, or

arguments as they may desire.

Communications should identify the

Rules Docket number and be submitted

in triplicate to the address specified

under the caption ADDRESSES. All

communications received on or before

the closing date for comments will be

considered, and this rule may be

amended in light of the comments

received. Factual information that

supports the commenter’s ideas and

suggestions is extremely helpful in

evaluating the effectiveness of the AD