Federal Register / Vol. 61, No. 112 / Monday, June 10, 1996 / Rules and Regulations 29271

been eliminated, the request should include

specific proposed actions to address it.

Note 2: Beech (Raytheon) Model BAe 125

series 800B and BAe 125 series 1000B

airplanes are similar in design to the

airplanes that are subject to the requirements

of this AD and, therefore, also may be subject

to the unsafe condition addressed by this AD.

However, as of the effective date of this AD,

those models are not type certificated for

operation in the United States. Airworthiness

authorities of countries in which the Model

BAe 125 series 800B and BAe 125 series

1000B airplanes are approved for operation

should consider adopting corrective action,

applicable to those models, that is similar to

the corrective action required by this AD.

Compliance: Required as indicated, unless

accomplished previously.

To prevent incorrect fault displays in the

cockpit and intermittent fault symptoms in

the engine starting and battery emergency

control circuits, as a result of imperfect

soldered connections, accomplish the

following:

(a) Within 6 months after the effective date

of this AD, perform an inspection to

determine if each diode soldered connection

is clean and functionally sound, in

accordance with Hawker Service Bulletin SB

24–317, dated December 22, 1994. If any

diode soldered connection is not clean or not

functionally sound, prior to further flight,

remake the soldered connection or replace

the diode with a new diode, in accordance

with the service bulletin.

(b) 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, FAA,

Transport Airplane Directorate. 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.

(c) 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.

(d) The inspection, remake, and

replacement shall be done in accordance

with Hawker Service Bulletin SB 24–317,

dated December 22, 1994. 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 Raytheon Corporate Jets,

Inc., Customer Support Department, Adams

Field, P.O. Box 3356, Little Rock, Arkansas

72203. 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.

(e) This amendment becomes effective on

July 15, 1996.

Issued in Renton, Washington, on May 31,

1996.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 96–14226 Filed 6–7–96; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 39

[Docket No. 93–ANE–48; Amendment 39–

9586; AD 96–09–10]

RIN 2120–AA64

Airworthiness Directives; Textron

Lycoming Reciprocating Engines

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Final rule.

SUMMARY: This amendment supersedes

an existing airworthiness directive (AD),

applicable to certain Textron Lycoming

reciprocating engines, that currently

requires replacement of sintered iron

impellers in oil pumps. This

amendment continues to require

replacement of sintered iron impellers,

but also requires replacement of

aluminum impellers. This amendment

is prompted by reports of additional oil

pump failures caused by aluminum

impellers, which do not have the

reliability of the hardened steel

impellers. The actions specified by this

AD are intended to prevent an oil pump

failure due to impeller failure, which

could result in an engine failure.

DATES: Effective July 15, 1996.

The incorporation by reference of

certain publications listed in the

regulations is approved by the Director

of the Federal Register as of July 15,

1996.

ADDRESSES: The service information

referenced in this AD may be obtained

from any Textron Lycoming Distributor

or Textron Lycoming, Reciprocating

Engine Division, 652 Oliver St.,

Williamsport, PA 17701; telephone

(717) 327–7278, fax (717) 327–7022.

This information may be examined at

the Federal Aviation Administration

(FAA), New England Region, Office of

the Assistant Chief Counsel, 12 New

England Executive Park, Burlington, MA

01803–5299; or at the Office of the

Federal Register, 800 North Capitol

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

FOR FURTHER INFORMATION CONTACT:

Richard Fiesel, Aerospace Engineer,

New York Aircraft Certification Office,

FAA, Engine and Propeller Directorate,

10 Fifth Street, Valley Stream, NY

11581; telephone (516) 256–7504, fax

(516) 568–2716.

SUPPLEMENTARY INFORMATION: On August

14, 1981, the Federal Aviation

Administration (FAA) issued

airworthiness directive (AD) 81–18–04,

Amendment 39–4199 (46 FR 43134,

August 27, 1981), to require

replacement of sintered iron oil pump

impellers and oil pump shafts with

impellers and shafts made of aluminum

or hardened steel in certain Textron

Lycoming reciprocating engines. That

action was prompted by reports of oil

pump failures. Subsequent to the

publication of AD 81–18–04, the FAA

issued two revisions to AD 81–18–04;

they are: 81–18–04R1, Amendment 39–

4258 (46 FR 56157, November 16, 1981),

effective November 19, 1981, and AD

81–18–04R2, Amendment 39–4395 (47

FR 23691, June 1, 1982), effective June

7, 1982.

A proposal to amend part 39 of the

Federal Aviation Regulations (14 CFR

part 39) by superseding AD 81–18–04R2

was published in the Federal Register

on January 3, 1994 (59 FR 35). That

action proposed to require replacing

sintered iron and aluminum impellers

and shafts with hardened steel impellers

and shafts, in accordance with Avco

Lycoming Division Service Bulletin (SB)

No. 381C, dated November 7, 1975;

Avco Lycoming Textron SB No. 385C,

dated October 3, 1975; Avco Lycoming

Textron SB No. 454 B, dated January 2,

1987; Avco Lycoming Textron SB No.

455 D, dated January 2, 1987; and

Textron Lycoming SB No. 456 F, dated

February 8, 1993.

Interested persons have been afforded

an opportunity to participate in the

making of this amendment. Due

consideration has been given to the

comments received.

Several commenters state that it is not

necessary to replace the aluminum

impeller with a steel impeller, as they

consider the aluminum impeller’s

reliability to be adequate. The FAA does

not concur. The FAA’s analysis of seven

years of Service Difficulty Reports

indicates that the aluminum impeller

does not have the reliability of the

hardened steel impeller and is only

slightly more reliable that the sintered

iron impeller. Based on that analysis the

FAA has issued Safety Recommendation

92.052 that recommends replacement of

the aluminum impeller within 100

hours time in service (TIS).

Several commenters state that the

aluminum impeller should be replaced

at overhaul rather than at 750 hours TIS

because of the difficulty of

accomplishing the modification without

engine disassembly and thereby
29272 Federal Register / Vol. 61, No. 112 / Monday, June 10, 1996 / Rules and Regulations

possibly introducing maintenance errors

with resultant engine failure. The FAA

concurs. The FAA has revised the

compliance time for replacement of the

aluminum impeller from within 750

hours after the effective date of the AD

to the next overhaul. However, the FAA

has included a calendar end-date of five

years after the effective date of this AD.

Considering the low time accumulation

rate for the types of aircraft involved, a

large percentage will reach 500–750

hours TIS within five years.

Some commenters question the

accuracy of 4,000 as the number of

affected engines. The FAA concurs. The

4,000 number was carried over from AD

81–18–04 and represented the number

of engines that incorporated the sintered

iron impeller. The number of aluminum

impellers, Part Number LW–13775,

installed in engines is much greater. The

FAA estimates 45,000 aluminum

impellers in service. The FAA has

therefore revised the economic analysis

to account for this greater number.

One commenter states that the AD

omits a required modification of older

pump housings, as referenced in SB’s

1164 and 1341. The FAA does not

concur. The earlier configuration

incorporates a fixed shaft and cotter pin

with a different aluminum impeller.

That configuration is not affected by this

AD. The FAA has clarified the

applicability of this AD to state that

only aluminum impellers, P/N LW

13775, are affected.

Some commenters state that only

aluminum impellers, P/N LW 13775,

should be affected by this AD. The FAA

concurs and has revised this AD

accordingly.

One commenter states that the AD

addresses three different categories of

engines as indicated in SB’s 454, 455,

and 456, and therefore should address

each engine type separately. The FAA

does not concur. The NPRM combined

the engines that are affected by SB 454

and SB 455 because these engines have

a similar design, are affected by the

same unsafe condition, and have the

same compliance requirements. The

FAA has determined that combining the

engine types eliminates redundancy and

makes for easier reading. Textron

Lycoming is in the process of issuing a

new SB to replace SB’s 454, 455, and

456.

One commenter states that the AD

should address only Textron Lycoming

impellers, P/N LW 13775, because

impellers manufactured by other

companies under a FAA Parts

Manufacturer Approval (PMA) have

excellent reliability. The FAA does not

concur. The FAA’s analysis of the

Service Difficulty Reports and Accident/

Incident reports does not support

distinguishing between impellers

manufactured by Textron and impellers

manufactured by other companies. The

Service Difficulty Reports do not always

list the P/N, or manufacturer, of the

failed impeller. Some are simply

referred to as ‘‘aluminum impeller.’’

Also, the format of the Accident/

Incident Reports does not include P/N.

Therefore, unless it can be shown by

reliability data that a PMA part has a

significantly better failure rate than does

Textron P/N LW 13775, the FAA must

include all similar aluminum impellers

in the AD.

One commenter states that all sintered

iron impellers should be removed

within 25 hours TIS. The FAA does not

concur. This AD reduces the

compliance time from 2,000 hours TIS

to 100 hours TIS for engines affected by

SB 456. The FAA has determined that

a further reduction to 25 hours TIS is

not justified, and would cause an undue

hardship to operators.

Since publication of the NPRM, the

FAA has reviewed and approved the

technical contents of Textron Lycoming

SB No. 524, dated September 1, 1995,

that combines the requirements of, and

supersedes Service Bulletin 381, 385,

454, 455, and 456; and SI No. 1009AJ,

dated July 1, 1992, that describes

established time between overhaul

(TBO) for Textron Lycoming

reciprocating engines.

In addition, this final rule reduces the

original time of compliance of certain

engines from 2,000 hours, required by

paragraph (c) of AD 81–18–04 to 100

hours TIS after the effective date of this

AD.

After careful review of the available

data, including the comments noted

above, the FAA has determined that air

safety and the public interest require the

adoption of the rule with the changes

described previously. The FAA has

determined that these changes will not

increase the scope of the AD.

There are approximately 45,000 oil

pumps of the affected design installed

in Textron Lycoming reciprocating

engines in the worldwide fleet. The

FAA estimates that 29,000 oil pumps

installed on aircraft of U.S. registry will

be affected by this AD, that it will take

approximately 4.5 work hours per oil

pump to accomplish the required

actions, and that the average labor rate

is $60 per work hour. Required parts

will cost approximately $270. Based on

these figures, the total cost impact of the

AD on U.S. operators is estimated to be

$15,660,000.

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 final evaluation has

been prepared for this action and it is

contained in the Rules Docket. A copy

of it 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 USC 106(g), 40113, 44701.

§ 39.13 [Amended]

2. Section 39.13 is amended by

removing Amendment 39–4199 (46 FR

43134, August 27, 1981) and by adding

a new airworthiness directive,

Amendment 39–9586, to read as

follows:

96–09–10 Textron Lycoming: Amendment

39–9586. Docket 93–ANE–48.

Supersedes AD 81–18–04 R2,

Amendment 39–4395.

Applicability: Textron Lycoming O–235,

O–290, O–320, IO–320, AIO–320, AEIO–320,

LIO–320, O–340, O–360, IO–360, LIO–360,

AIO–360, HO–360, HIO–360, LO–360, LIO–

360, TIO–360, TO–360, LTO–360, VO–360,

IVO–360, O–540, and IO–540 series

reciprocating engines, except for the

following models: O–320–H2AD, O–360–

E1A6D, LO–360–E1A6D, TO–360–E1A6D,

LTO–360–E1A6D, IO–540–P1A5, IO–540–

R1A5, IO–540–S1A5, and O–540 and IO–540

series engines built with large capacity oil

pumps and dual magnetos designated with
Federal Register / Vol. 61, No. 112 / Monday, June 10, 1996 / Rules and Regulations 29273

‘‘5D’’ in the model suffix; for example, IO–

540–K1A5D. These engines are installed on

but not limited to the following aircraft:

various models of single and twin engine

powered Cessna, Piper, Mooney, Beech,

Gulfstream American, Maule, and Socata.

Note 1: This AD may not contain an

exhaustive list of aircraft that utilize the

affected engines because other aircraft may

have an affected engine installed through, for

example, approvals made by Supplemental

Type Certificate, or FAA Form 337, ‘‘Major

Repair and Alteration.’’ It is the

responsibility of each aircraft owner,

operator, and person returning that aircraft to

service to determine if that aircraft has an

affected engine.

Note 2: This AD applies to each engine

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

engines that have been modified, altered, or

repaired so that the performance of the

requirements of this AD is affected, the

owner/operator must use the authority

provided in paragraph (f) to request approval

from the FAA. This approval may address

either no action, if the current configuration

eliminates the unsafe condition, or different

actions necessary to address the unsafe

condition described in this AD. Such a

request should include an assessment of the

effect of the changed configuration on the

unsafe condition addressed by this AD. In no

case does the presence of any modification,

alteration, or repair remove any engine from

the applicability of this AD.

Compliance: Required as indicated, unless

accomplished previously.

To prevent oil pump failure due to

impeller failure, which could result in an

engine failure, accomplish the following:

(a) For Textron Lycoming Model HIO–360–

D1A, –E1AD, –E1BD, and –F1AD engines

with serial numbers (S/N) of L–22579–51A or

prior, except for the following: S/N L–22311–

51A through L–22313–51A, L–22396–51A,

L–22397–51A, L–22416–51A, L–22546–51A

through L–22549–51A, L–22563–51A, L–

22568–51A through L–22571–51A; for

Textron Lycoming Model HIO–360–D1A,

–E1AD, –E1BD, and –F1AD engines that were

overhauled in the field or remanufactured

prior to April 1, 1981, regardless of S/N; and

for engines listed by S/N in Textron

Lycoming Service Bulletin (SB) No. 455D,

dated January 2, 1987; accomplish the

following:

(1) Replace the sintered iron oil pump

impeller and shaft with a hardened steel

impeller and shaft in accordance with Avco

Lycoming Textron SB No. 454B, dated

January 2, 1987, or Avco Lycoming Textron

SB No. 455D, dated January 2, 1987, as

applicable, or Textron Lycoming SB No. 524,

dated September 1, 1995, within 25 hours

time in service (TIS) after the effective date

of this AD.

(2) No action is required if engines have

complied with AD 81–18–04, 81–18–04 R1,

or 81–18–04 R2, and have incorporated oil

pumps with a hardened steel impeller and

shaft. Engines that incorporate oil pumps

fitted with an aluminum impeller and shaft

must comply with paragraph (c) of this AD.

(b) For engines listed by S/N in Textron

Lycoming SB No. 456F, dated February 8,

1993, or Textron Lycoming SB No. 524, dated

September 1, 1995, that incorporate a

sintered iron impeller, accomplish the

following:

(1) Replace any sintered iron oil pump

impeller and shaft with a hardened steel

impeller and shaft in accordance with

Textron Lycoming SB No. 456F, dated

February 8, 1993, or Textron Lycoming SB

No. 524, dated September 1, 1995, within 100

hours TIS after the effective date of this AD,

or one year after the effective date of this AD,

whichever occurs first. Total time on the

sintered iron impeller must not exceed 2,000

hours TIS since new or overhaul, whichever

occurs later

(2) No action is required if engines have

complied with AD 81–18–04, 81–18–04 R1,

or 81–18–04 R2, and have incorporated oil

pumps with a hardened steel impeller and

shaft. Engines that incorporate oil pumps

fitted with an aluminum impeller and shaft

must comply with paragraph (c) of this AD.

(c) For all other affected engines, replace

any aluminum oil pump impeller and shaft

assembly with a hardened steel impeller and

shaft assembly in accordance with Avco

Lycoming Textron SB No. 455D, dated

January 2, 1987, or Textron Lycoming SB No.

456F, dated February 8, 1993, or Textron

Lycoming SB No. 524, dated September 1,

1995, as applicable, as follows:

(1) Replace at next engine overhaul (not to

exceed the hours specified, for the particular

engine model, in Textron Lycoming Service

Instruction 1009AJ, dated July 1, 1992), at

next oil pump removal, or 5 years after the

effective date of this AD, whichever occurs

first.

(2) No action is required if engines have

complied with AD 81–18–04, 81–18–04 R1,

or 81–18–04 R2, and have incorporated oil

pumps with a hardened steel impeller and

shaft.

Note: Engines originally manufactured

prior to 1970 did not incorporate sintered

iron impellers. For further information, refer

to engine maintenance/overhaul logbook

records, Lycoming build records, and the

following SB’s provide additional guidance:

Avco Lycoming Division SB No. 381C, dated

November 7, 1975, and Avco Lycoming

Textron SB No. 385C, dated October 3, 1975,

describe a method for determining if the

early design oil pump with aluminum/steel

impellers are installed. Avco Lycoming SB

No. 455A, dated August 18, 1981, and

Textron Lycoming SB No. 455B, dated

January 2, 1987, and Avco Lycoming SB No.

456, dated August 21, 1981, introduced steel

driving impeller, P/N 60746, and aluminum

driven impeller, P/N LW13775. Textron

Lycoming SB No. 524 includes information

regarding engines which may incorporate

aluminum impellers

(d) Engines that are subject to AD 75–08–

09 must have incorporated AD 75–08–09

before this AD can be accomplished.

(e) Sintered iron and aluminum impellers

approved under FAA Parts Manufacturer

Approval (PMA) are replacements for

affected part numbers of Lycoming impellers

and must also be replaced in accordance with

paragraphs (a), (b), or (c), as applicable, of

this AD.

(f) 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, New York

Aircraft Certification Office. The request

should be forwarded through an appropriate

FAA Maintenance Inspector, who may add

comments and then send it to the Manager,

New York Aircraft Certification Office.

Note: Information concerning the existence

of approved alternative method of

compliance with this AD, if any, may be

obtained from the New York Aircraft

Certification Office.

(g) 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 aircraft to

a location where the requirements of this AD

can be accomplished.

(h) The actions required by this AD shall

be done in accordance with the following

service bulletins:

Document No. Pages Date

Avco Lycoming Division SB No. 381C .......................................................................................................... 1–4 November 7, 1975.

Total pages: 4.

Avco Lycoming Textron SB No. 385C ........................................................................................................... 1–4 October 3, 1975.

Supplement No. 1 .......................................................................................................................................... 1 March 18, 1977.

Total pages: 5.

Avco Lycoming Textron SB No. 454B ........................................................................................................... 1–3 January 2, 1987.

Total pages: 3.

Avco Lycoming Textron SB No. 455D ........................................................................................................... 1–3 January 2, 1987.

Total pages: 3.

Textron Lycoming SB No. 456F .................................................................................................................... 1–3 February 8, 1993.

Total pages: 3.

Textron Lycoming SB No. 524 ....................................................................................................................... 1–3 September 1, 1995.

Attachment ..................................................................................................................................................... 1–4
29274 Federal Register / Vol. 61, No. 112 / Monday, June 10, 1996 / Rules and Regulations

Document No. Pages Date

Total pages: 9.

Textron Lycoming SI No. 1009AJ .................................................................................................................. 1–3 July 1, 1992.

Total pages: 3.

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 Textron Lycoming, Reciprocating

Engine Division, 652 Oliver St.,

Williamsport, PA 17701; telephone (717)

327–7278, fax (717) 327–7022. Copies may be

inspected 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.

(i) This amendment becomes effective on

July 15, 1996.

Issued in Burlington, Massachusetts, on

May 22, 1996.

Robert E. Guyotte,

Acting Manager, Engine and Propeller

Directorate, Aircraft Certification Service.

[FR Doc. 96–14223 Filed 6–7–96; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 39

[Docket No. 96–NM–109–AD; Amendment

39–9655; AD 96–11–15]

RIN 2120–AA64

Airworthiness Directives; Dornier

Model 328–100 Series Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Final rule; request for

comments.

SUMMARY: This document publishes in

the Federal Register an amendment

adopting Airworthiness Directive (AD)

96–11–15 that was sent previously to all

known U.S. owners and operators of

Dornier Model 328–100 series airplanes

by individual notices. This AD requires

that the Limitations Section of the FAAapproved Airplane Flight Manual

(AFM) be revised to restrict flight

altitude to a maximum of 10,000 feet

mean sea level (MSL). This AD also

requires replacement of ‘‘lightweight’’

windshields (left and right-hand) with

new windshields. This amendment is

prompted by reports indicating that the

outer face ply of ‘‘lightweight’’

windshields (left-hand and right-hand)

installed on these airplanes have

shattered or cracked while the airplane

was in flight. The actions specified by

this AD are intended to prevent

restriction of the flightcrew’s ability to

see through the windshields due to

shattering or cracking of the

windshields, and to continue to control

the airplane safely.

DATES: Effective June 17, 1996, to all

persons except those persons to whom

it was made immediately effective by

emergency AD 96–11–15, issued May

24, 1996, which contained the

requirements of this amendment.

The incorporation by reference of

certain publications listed in the

regulations is approved by the Director

of the Federal Register as of June 17,

1996.

Comments for inclusion in the Rules

Docket must be received on or before

August 9, 1996.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–103,

Attention: Rules Docket No. 96–NM–

109–AD, 1601 Lind Avenue, SW.,

Renton, Washington 98055–4056.

The applicable service information

may be obtained from Dornier Luftfahrt

GmbH, P.O. Box 1103, D–82230

Wessling, Germany. 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:

Connie Beane, Aerospace Engineer,

Standardization Branch, ANM–113,

FAA, Transport Airplane Directorate,

1601 Lind Avenue, SW., Renton,

Washington 98055–4056; telephone

(206) 227–2796; fax (206) 227–1320.

SUPPLEMENTARY INFORMATION: On May

24, 1996, the FAA issued emergency AD

96–11–15, which is applicable to all

Dornier Model 328–100 series airplanes.

That action was prompted by reports

indicating that the outer face ply of

‘‘lightweight’’ windshields (left-hand

and right-hand) installed on several of

these airplanes had shattered or cracked

during flight of the airplane.

Investigation revealed that foreign

object damage (FOD) from sand or other

runway debris may cause small pits in

the windshield. During flight, normal

windshield flexing from cabin pressure

loads, or normal thermal stresses may

result in shattering or cracking of the

outer face ply of the windshield. The

observed failure rate is such that both

the pilot’s and copilot’s windshields

may be affected during the same flight.

This condition, if not corrected, could

result in a restriction of the flightcrew’s

ability to see through the windshield,

and to continue to control the airplane

safely.

The design of these ‘‘lightweight’’

windshields may not meet the

requirements of the Federal Aviation

Regulations, and has not been approved

by the FAA for installation on U.S.-

registered airplanes. Additionally, the

design of these windshields has not

been approved by the LuftfahrtBundesamt (LBA), which is the

airworthiness authority for Germany, for

installation on Dornier Model 328–100

series airplanes.

Explanation of Relevant Service

Information

Dornier has issued Service Bulletin

SB–328–56–165, dated April 19, 1996,

which describes procedures for

replacing ‘‘lightweight’’ windshields

with new windshields that are not

susceptible to the subject cracking and

shattering.

U.S. Type Certification of the Airplane

The Dornier Model 328–100 series

airplane is manufactured in Germany

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.

Explanation of the Requirements of the

Rule

Since the unsafe condition described

is likely to exist or develop on other

airplanes of the same type design

registered in the United States, the FAA

issued emergency AD 95–11–15 to

prevent restriction of the flightcrew’s

ability to see through the windshields

due to shattering or cracking of the

windshields, and to continue to control

the airplane safely. The AD requires that

the Limitations Section of the FAAapproved Airplane Flight Manual

(AFM) be revised to restrict flight

altitude to a maximum of 10,000 feet

mean sea level (MSL). This restriction is

intended to limit the flexing of the

windshield under cabin pressure loads

and reduce the potential for cracks to

develop.

The AD also requires replacement of

‘‘lightweight’’ windshields (left- and

right-hand) with new windshields. This