Airworthiness Directives; Jetstream Model ATP Airplanes

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 94-NM-151-AD]

Airworthiness Directives; Jetstream Model ATP Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing

airworthiness directive (AD), applicable to all Jetstream Model ATP

airplanes, that currently requires revising the Airplane Flight Manual

(AFM) to prohibit flight in certain freezing precipitation conditions.

This action would add a requirement to install certain modifications of

the engine air intake system. This proposal is prompted by the

development of certain modifications of the engine air intake system

intended to permit operation of these airplanes in freezing

precipitation conditions. The actions specified by the proposed AD are

intended to prevent engine power rollback in flight during freezing

precipitation conditions.

DATES: Comments must be received by February 9, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

Administration (FAA), Transport Airplane Directorate, ANM-103,

Attention: Rules Docket No. 94-NM-151-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. -

The service information referenced in the proposed rule 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.

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) 227-1320.

SUPPLEMENTARY INFORMATION:

Comments Invited -

Interested persons are invited to participate in the making of the

proposed 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 above. All

communications received on or before the closing date for comments,

specified above, will be considered before taking action on the

proposed rule. The proposals contained in this notice may be changed in

light of the comments received. -

Comments are specifically invited on the overall regulatory,

economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with

the substance of this proposal will be filed in the Rules Docket. -

Commenters wishing the FAA to acknowledge receipt of their comments

submitted in response to this notice must submit a self-addressed,

stamped postcard on which the following statement is made: ``Comments

to Docket Number 94-NM-151-AD.'' The postcard will be date stamped and

returned to the commenter. Availability of NPRMs -

Any person may obtain a copy of this NPRM by submitting a request

to the FAA, Transport Airplane Directorate, ANM-103, Attention: Rules

Docket No. 94-NM-151-AD, 1601 Lind Avenue, SW., Renton, Washington

98055-4056.

Discussion

On March 31, 1994, the FAA issued AD 94-08-01, amendment 39-8872

(59 FR 25290, May 16, 1994), applicable to all British Aerospace Model

ATP airplanes, which requires revision of the Limitations Section of

the FAA-approved Airplane Flight Manual (AFM) Limitations Section to

prohibit flight in certain freezing precipitation conditions. That

action was prompted by reports of engine power rollback (loss of engine

power) that occurred during flight in environmental conditions

involving freezing precipitation. The required AFM revision was

intended as an interim measure to prevent loss of multiple engine power

during flight in freezing precipitation.

AD 94-08-01 also provided for certain optional actions that, when

all of them were accomplished, would terminate the required prohibition

of flight into certain icing conditions. These actions were:

1. Revising the Limitations Section and the Normal Procedures

Section of the FAA-approved AFM to include specific procedures for

operation in icing conditions;

2. Incorporating a revision into the FAA-approved maintenance

program that provides for replacement of engine igniter plugs at

specific intervals;

3. Installing an eductor plate over the exhaust port of the engine

air intake system;

4. Installing engine air inlet ducts that incorporate electrical

de-ice heaters, and perform associated electrical system changes; and

5. Revising the FAA-approved maintenance program to include

repetitive visual inspections of the heater mats for damage at specific

intervals.

In the preamble to AD 94-08-01, the FAA indicated that the actions

required by that AD were considered ``interim action'' and that further

rulemaking action was being considered. The FAA has now determined that

the installation of these previously optional modifications and certain

revision of the AFM will positively address the unsafe condition that

is the subject of AD 94-08-01 by preventing loss of engine power during

flight in freezing precipitation. The actions proposed in this notice

follow from that determination.

Since the issuance of AD 94-08-01, Jetstream has issued two

revisions of the Limitations, Normal Procedures, and Abnormal

Procedures Sections of the AFM to include the information specified in

Temporary Revision T/33, Issue 1, dated November 1, 1993; and Temporary

Revision T/38, Issue 1, dated February 16, 1994. These documents

provide procedures to the flight crew for operation in icing

conditions.

Jetstream Service Bulletin ATP-80-06, Revision 2, dated October 16,

1994, describes procedures for replacing the engine igniter plug at

repetitive intervals.

Additionally, Jetstream has issued three service bulletins

describing various actions that, if accomplished, eliminate the need

for the repetitive replacement of the engine igniter plugs. These

service bulletins are:

1. Jetstream ATP-30-39-30146A, dated July 29, 1994, which describes

procedures for installation of new de-ice timers on both engines.

2. Jetstream ATP-30-37-30143A, dated August 1, 1994; and Revision

1, dated September 5, 1994; which describe procedures for associated

wiring changes to the automatic duct heat.

3. Jetstream ATP-80-7-30141A, Revision 2, dated November 4, 1994,

which describes procedures for installation of an automatic ignition

system for the engine and revision of the Airplane Flight Manual by

installation of information in Temporary Revision T/42, Issue 1, dated

August 12, 1994.

Jetstream also has issued Service Bulletins ATP-54-12-35274A, dated

September 28, 1993; and Revision 1, dated December 15, 1993; which

describe procedures for installation of an eductor plate over the

exhaust port of the engine air intake system. (Revision 1 of this

service bulletin contains additional procedures for an inspection to

detect any aperture profile mismatch on any eductor plate that was

installed in accordance with the original issue of the service

bulletin.)

Additionally, Jetstream has issued Service Bulletins ATP-54-13-

35274B, Revision 1 (Modification 35274B), dated July 8, 1994; and

Revision 2, dated August 18, 1994; which describe procedures for

installing an improved engine air intake modification. These service

bulletins specify a separate modification configuration for each of two

serial number blocks of airplanes. Revision 2 of this service bulletin

also references an acceptable alternative modification of the engine

air intake system (which is described in Jetstream Service Bulletin ATP

54-15-35274E, dated July 27, 1994.) The Civil Aviation Authority (CAA),

which is the airworthiness authority for the United Kingdom, has

classified Jetstream Service Bulletin ATP-54-13-35274B, Revision 2,

dated August 18, 1994, as mandatory in order to assure the continued

airworthiness of these airplanes in the United Kingdom.

Jetstream also has issued Service Bulletin ATP-54-14, dated October

14, 1993, which describes procedures for repetitive visual inspections

of the heater mats for damage, and replacement, if necessary.

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.

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, the proposed AD would supersede AD 94-08-01 to

require the following actions:

1. Revision of the Limitations, Normal Procedures, and Abnormal

Procedures Sections of the FAA-approved AFM to include the information

specified in Temporary Revision T/33, Issue 1, dated November 1, 1993,

and Temporary Revision T/38, Issue 1, dated February 16, 1994, which

provide procedures for operation in icing conditions;

2. Revision of the FAA-approved maintenance program to include

replacement of engine igniter plugs at certain specified intervals;

3. Installation of an eductor plate over the exhaust port of the

engine air intake system;

4. Installation of certain modifications of the engine air intake

system; and

5. Revision of the FAA-approved maintenance program to include

repetitive visual inspections of the heater mats for damage at specific

intervals, and replacement of the engine air intake, if necessary.

These proposed actions would be required to be accomplished in

accordance with the service bulletins described previously.

This proposed AD would also provide for an optional terminating

action for the proposed repetitive visual inspections of the heater

mats on airplanes that have accomplished the alternative engine air

intake modification in accordance with Jetstream Service Bulletin ATP-

54-15-35274E, dated July 27, 1994.

This proposed AD would also provide optional terminating actions

for the proposed requirement to repetitively replace the engine igniter

plugs.

Additionally, this action would revise the applicability of the

proposed rule by limiting the affected airplanes to those called out in

Jetstream Service Bulletin ATP 54-13-35274B, Revision 2, dated August

18, 1994.

As a result of recent communications with the Air Transport

Association (ATA) of America, the FAA has learned that, in general,

some operators may misunderstand the legal effect of AD's on airplanes

that are identified in the applicability provision of the AD, but that

have been altered or repaired in the area addressed by the AD. The FAA

points out that all airplanes identified in the applicability provision

of an AD are legally subject to the AD. If an airplane has been altered

or repaired in the affected area in such a way as to affect compliance

with the AD, the owner or operator is required to obtain FAA approval

for an alternative method of compliance with the AD, in accordance with

the paragraph of each AD that provides for such approvals. A note has

been included in this notice to clarify this requirement.

The FAA estimates that 10 airplanes of U.S. registry would be

affected by this proposed AD, that it would take approximately 150 work

hours per airplane to accomplish the proposed actions, and that the

average labor rate is $60 per work hour. Required parts would be

provided by the manufacturer at no cost to the operator. Based on these

figures, the total cost impact of the proposed AD on U.S. operators is

estimated to be $90,000, or $9,000 per airplane.

The total cost impact figure discussed above is based on

assumptions that no operator has yet accomplished any of the proposed

requirements of this AD action, and that no operator would accomplish

those actions in the future if this AD were not adopted.

The regulations proposed herein would 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

proposal would not have sufficient federalism implications to warrant

the preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this proposed

regulation (1) is not a ``significant regulatory action'' under

Executive Order 12866; (2) is not a ``significant rule'' under the DOT

Regulatory Policies and Procedures (44 FR 11034, February 26, 1979);

and (3) if promulgated, 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 draft

regulatory 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, Safety.

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the

Administrator, the Federal Aviation Administration proposes to amend

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. App. 1354(a), 1421 and 1423; 49 U.S.C.

106(g); and 14 CFR 11.89.

Sec. 39.13 [Amended]

2. Section 39.13 is amended by removing amendment 39-8872 (59 FR

25290, May 16, 1994), and by adding a new airworthiness directive (AD),

to read as follows:

Jetstream Aircraft Limited (Formerly British Aerospace Commercial

Aircraft, Limited): Docket 94-NM-151-AD. Supersedes AD 94-08-01,

Amendment 39-8872.

Applicability: Model ATP airplanes, as listed in Jetstream

Service Bulletin ATP 54-13-35274B, Revision 2, dated August 18,

1994, 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 use the authority

provided in paragraph (e) 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 airplane from the applicability of this AD.

Compliance: Required as indicated, unless accomplished

previously.

To prevent loss of multiple engine power during flight in

freezing precipitation, accomplish the following:

(a) Within 30 days after June 15, 1994 (the effective date of AD

94-08-01, amendment 39-8872), revise the Limitations Section of the

FAA-approved Airplane Flight Manual (AFM) to include the following

statement. This may be accomplished by inserting a copy of this AD

in the AFM.

``Flight is prohibited into forecast or reported freezing

precipitation conditions where the outside air temperature is

between +5 deg.C and -5 deg.C.''

(b) Within 72 days after the effective date of this AD,

accomplish the actions specified in paragraphs (b)(1), (b)(2),

(b)(3), (b)(4), (b)(5), and (b)(6), which will constitute

terminating action for the AFM revision required by paragraph (a) of

this AD. Once these actions are completed, the AFM revision required

by paragraph (a) may be removed.

(1) Revise the Limitations Section and the Normal Procedures

Section of the FAA-approved AFM, to include the information

specified in Temporary Revision T/33, Issue 1, dated November 1,

1993, and Temporary Revision T/38, Issue 1, dated February 16, 1994,

which introduce procedures for operation in icing conditions, as

specified in the temporary revision; and operate the airplane in

accordance with those limitations and procedures.

Note 2: This may be accomplished by inserting copies of

Temporary Revision T/33 and T/38 in the AFM. When these temporary

revisions have been incorporated into general revisions of the AFM,

the general revisions may be inserted in the AFM, provided the

information contained in the general revision is identical to that

specified in Temporary Revision T/33 and T/38.

(2) Incorporate a revision into the FAA-approved maintenance

program that provides for replacement of engine igniter plugs at the

intervals specified in Jetstream Service Bulletin ATP-80-06,

Revision 1, dated October 22, 1993, or Revision 2, dated October 16,

1994. Initial replacement of an engine igniter plug with a new plug

shall be accomplished prior to the accumulation of 200 total hours

time-in-service on the engine igniter plug, or within 50 hours time-

in-service after incorporating the maintenance program revision,

whichever occurs later.

(3) Install an eductor plate over the exhaust port of the engine

air intake system in accordance with Jetstream Service Bulletin ATP-

54-12-35274A, dated September 28, 1993, or Revision 1, dated

December 15, 1993. Any eductor plate installed in accordance with

the original issue of the service bulletin must be inspected for any

aperture profile mismatch, in accordance with paragraph 2., Part B.,

of the Accomplishment Instructions of Revision 1 of the service

bulletin. If any mismatch is found that exceeds the limit specified

in that service bulletin, prior to further flight, the discrepancy

must be corrected in accordance with paragraph 2., Part C, of

Revision 1 of the service bulletin.

(4) For airplanes having constructor numbers 2007, 2010 through

2016 inclusive, 2020 through 2022 inclusive, 2028, 2029, 2032, 2034

through 2037 inclusive, 2041 through 2044 inclusive, 2051, 2053, and

2056: Install engine air inlet ducts that incorporate electrical de-

ice heaters with increased power and area, and perform associated

electrical system changes, in accordance with the Accomplishment

Instructions, in Jetstream Service Bulletin ATP-54-13-35274B dated

October 9, 1993, or Parts A through F of Revision 1, dated July 8,

1994, or Revision 2, dated August 18, 1994.

(5) For airplanes having constructor numbers 2002 through 2006

inclusive, 2008, 2009, 2017 through 2019 inclusive, 2023 through

2027 inclusive, 2030, 2031, 2033, 2038 through 2040 inclusive, 2045

through 2050 inclusive, 2052, 2054 through 2055 inclusive, and 2057

through 2063 inclusive: Install engine air inlet ducts that

incorporate electrical de-ice heaters with increased power, in

accordance with the Accomplishment Instructions, Part G, of

Jetstream Service Bulletin ATP-54-13-35274B, Revision 2, dated

August 18, 1994.

Note 3: Installation of engine air inlet ducts in accordance

with Jetstream Service Bulletin ATP-54-15-35274E, dated July 27,

1994, is considered acceptable for compliance with either paragraph

(b)(4) or (b)(5) of this AD.

(6) Revise the FAA-approved maintenance program to include

repetitive visual inspections for damage of the heater mats at

intervals not to exceed 50 hours time-in-service, in accordance with

Jetstream Service Bulletin ATP-54-14, dated October 14, 1993; and,

if any damage is found, prior to further flight, replace the engine

air intake in accordance with the service bulletin.

(c) The following installations on both engines constitute

terminating action for the repetitive replacement of the engine

igniter plugs required by paragraph (b)(2) of this AD:

(1) Installation of new de-ice timers in accordance with

Jetstream Service Bulletin ATP-30-39-30146A dated July 29, 1994,

(2) Wiring changes to incorporate automatic duct heat when

engine air intake lip heat is selected ``on,'' in accordance with

Jetstream Service Bulletin ATP-30-37-30143A, dated August 1, 1994,

or Revision 1, dated September 5, 1994, and

(3) Installation of an engine automatic ignition system in

accordance with Jetstream Service Bulletin ATP 80-7-30141A, Revision

2, dated November 4, 1994; and an associated revision of the FAA-

approved Airplane Flight Manual (AFM) by incorporating the

information contained in Temporary Revision T/42, Issue 1, dated

August 12, 1994.

(d) For airplanes on which the engine air intake (Modification

35274E) has been installed in accordance with Jetstream Service

Bulletin ATP-54-15-35274E, dated July 27, 1994: The installation of

engine duct de-ice overheat protection (Modification 35274D) in

accordance with Jetstream Service Bulletin ATP-30-44-35274D, dated

August 12, 1994, constitutes terminating action for the repetitive

inspections required by paragraph (b)(6) of 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,

FAA, Transport Airplane Directorate. Operators shall submit their

requests through an appropriate FAA Principal Inspector, who may add

comments and then send it to the Manager, Standardization Branch,

ANM-113.

Note 4: 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 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.

Issued in Renton, Washington, on December 22, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-32033 Filed 12-28-94; 8:45 am]

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