Airworthiness Directives; Jetstream Aircraft Limited (Formerly British Aerospace, Regional Airlines Limited) Jetstream Model 3101 Airplanes

SUMMARY: This document proposes to revise an earlier proposed

airworthiness directive (AD), which would have superseded AD 91-08-01.

That AD currently requires the following on Jetstream Aircraft Limited

(JAL) Jetstream Model 3101 airplanes: revising the maximum speed for

flaps at 50 degrees from 153/149 knots indicated airspeed (KIAS) to 130

KIAS; and limiting the maximum flap extension to 20 degrees anytime ice

is present on the airplane. The previous notice proposed to provide the

option of incorporating a flap system modification that would eliminate

the requirements of AD 91-08-01. Since publication of that proposal,

the Federal Aviation Administration (FAA) has re-examined all

information related to this subject, and has determined that the flap

system modification should be made mandatory rather than optional. The

proposed actions are intended to prevent sudden pitch down of the

airplane during icing conditions, which could lead to loss of control

of the airplane.

DATES: Comments must be received on or before December 16 1994.

ADDRESSES: Submit comments in triplicate to the FAA, Central Region,

Office of the Assistant Chief Counsel, Attention: Rules Docket No. 92-

CE-22-AD, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106.

Comments may be inspected at this location between 8 a.m. and 4 p.m.,

Monday through Friday, holidays excepted.

Service information that applies to the proposed AD may be obtained

from Jetstream Aircraft Limited, Manager Product Support, Prestwick

Airport, Ayrshire, KA9 2RW Scotland; telephone (44-292) 79888;

facsimile (44-292) 79703; or Jetstream Aircraft Inc., Librarian, P.O.

Box 16029, Dulles International Airport, Washington, DC 20041-6029;

telephone (703) 406-1161; facsimile (703) 406-1469. This information

also may be examined at the Rules Docket at the address above.

FOR FURTHER INFORMATION CONTACT: Mr. Raymond A. Stoer, Program Officer,

Brussels Aircraft Certification Office, FAA, Europe, Africa, and Middle

East Office, c/o American Embassy, B-1000 Brussels, Belgium; telephone

(322) 513.3830; facsimile (322) 230.6899; or Mr. John P. Dow, Sr.,

Project Officer, Small Airplane Directorate, Airplane Certification

Service, FAA, 1201 Walnut, suite 900, Kansas City, Missouri 64106;

telephone (816) 426-6932; facsimile (816) 426-2169.

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 should 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 that summarizes 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 No. 92-CE-22- 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, Central Region, Office of the Assistant Chief Counsel,

Attention: Rules Docket No. 92-CE-22-AD, Room 1558, 601 E. 12th Street,

Kansas City, Missouri 64106.

Discussion

A proposal to amend part 39 of the Federal Aviation Regulations (14

CFR part 39) to include an AD that would apply to certain JAL Jetstream

Model 3101 airplanes was published in the Federal Register on July 8,

1992 (57 FR 30174). That action proposed to supersede AD 91-08-01 with

a new AD that would (1) retain the flap system operating revision and

limitation currently required by AD 91-08-01; and (2) limit the

applicability to only those airplanes that do not have the flap system

modified in accordance with British Aerospace (BAe) Service Bulletin

27-JA 910541.

Interested persons have been afforded an opportunity to participate

in the making of this amendment. One comment was received in agreement

with the proposed AD and no comments were received concerning the FAA's

determination of the cost upon the public.

Since issuing that action, the FAA has re-examined all available

information on this issue, and has determined that the limitation of

maximum flap setting of 20 degrees in icing conditions presents an

unsafe condition in certain circumstances.

The Jetstream Model 3101 airplane has a feature known as ``lift

dump'', which allows for proper deceleration by automatically extending

flaps from the 50 degree position to the 70 degree position when the

nose wheel strut is compressed during landing. When landing with a flap

setting of 20 degrees, ``lift dump'' is not normally available, which

can make deceleration more dependent upon propeller reverse or manual

selection.

Propeller reverse is utilized in normal operation as an aid in

reducing landing roll distance. The other option is manually selecting

flaps from 20 degrees to 50 degrees immediately after touchdown while

the airplane is traveling at a higher speed. When the operator selects

the 50-degree position with all ground logic constraints satisfied, the

flaps will extend to the 70-degree position. This technique can result

in high aerodynamic loads upon the flap, which could cause structural

damage that, if not detected and corrected, could result in loss of

airplane directional control caused by failure of the flap system.

Also, there is a temporary increase in wing lift when manually

extending the wings from 20 degrees to 35 degrees, which could result

in the airplane becoming airborne or a reduction of directional control

and braking force.

Because ``lift dump'' is available with the flaps at the 35-degree

position during landing, the FAA has determined that (1) the flap

system modification that allows the use of flaps at 35-degrees with ice

visible should be incorporated; and (2) AD action should be taken to

prevent sudden pitch down of the airplane during icing conditions,

which could lead to loss of control of the airplane.

Since incorporating the 35 degrees flap modification into the

notice of proposed rulemaking specifies additional procedures that go

beyond the scope of what was originally proposed, the notice has been

revised accordingly and the comment period has been reopened to provide

additional time for public comment. The proposed AD would supersede AD

91-08-01 with a new AD that would (1) retain the flap system operating

revision and limitation currently required until the 35-degree flap

system modification was incorporated; and (2) eventually require

incorporating the 35-degree flap system modification in accordance with

the instructions in Jetstream Aircraft Limited SB No. 27-JA 910541,

which consists of the following pages:

------------------------------------------------------------------------

Page Nos. Revision level Date

------------------------------------------------------------------------

2, 5 through 30 and 33 Revision 1............. November 11, 1991.

through 45.

31..................... Revision 2............. February 4, 1992.

1, 3, 4, and 32........ Revision 3............. November 16, 1992.

------------------------------------------------------------------------

The FAA estimates that 141 airplanes in the U.S. registry would be

affected by the proposed AD, that it would take approximately 23

workhours per airplane to accomplish the proposed modification, and

that the average labor rate is approximately $55 an hour. The

manufacturer will provide parts at no cost to the owner/operator. Based

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

operators is estimated to be $194,580. This figure is based on the

assumption that no affected owner/operator has incorporated the

proposed modification.

Jetstream Aircraft Limited has informed the FAA that 122

modification kits have been delivered to affected airplane owners/

operators. Since each of these airplane operators have incorporated

revised flight manual supplements, the FAA assumes that each of these

kits is installed on one of the affected airplanes. With this in mind,

the proposed cost impact upon U.S. operators would be reduced $168,300

from $194,580 to $26,220. In addition, Jetstream Aircraft Limited

informed the FAA that the other 19 affected airplanes are in the

storage inventory of their sister company JSX. The policy of JSX is to

incorporate this modification before distributing one of the affected

airplanes to an operator. Taking these factors into consideration, the

proposed AD would provide no economic cost impact upon U.S. operators.

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 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) 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 has been placed 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 AD 91-08-01, Amendment 39-

7007 (56 FR 24333, May 30, 1991), and adding a new AD to read as

follows:

Jetstream Aircraft Limited: Docket No. 92-CE-22-AD. Supersedes AD

91-08-01, Amendment 39-7007.

Applicability: Jetstream Model 3101 airplanes (all serial

numbers), certificated in any category, that do not have the flap

system modified in accordance with the ACCOMPLISHMENT INSTRUCTIONS

section of Jetstream Aircraft Limited Service Bulletin (SB) 27-JA

910541, which consists of the following pages and revision levels:

------------------------------------------------------------------------

Page Nos. Revision level Date

------------------------------------------------------------------------

2, 5 through 30 and 33 Revision 1............. November 11, 1991.

through 45.

31..................... Revision 2............. February 4, 1992.

1, 3, 4, and 32........ Revision 3............. November 16, 1992.

------------------------------------------------------------------------

Note 1: Compliance with a different revision level of the above-

referenced service bulletin fulfills the applicable requirements of

this AD.

Compliance: Required as indicated after the effective date of

this AD, unless already accomplished.

To prevent sudden pitch down of the airplane during icing

conditions, which could lead to loss of control of the airplane,

accomplish the following:

(a) Within the next 10 hours time-in-service (TIS) after June

10, 1991 (the effective date of superseded AD 91-08-01), accomplish

the following:

(1) Modify the operating limitations placards located on the

flight deck in accordance with Jetstream Alert SB No. 27-A-JA

910340, dated March 25, 1991. This modification will limit the

maximum flap extension speed at the 50-degree position to 130 knots

indicated airspeed (KIAS).

(2) Insert a copy of this AD into the limitations section of the

airplane flight manual.

(b) Within the next 25 hours TIS after June 10, 1991 (the

effective date of superseded AD 91-08-01), accomplish the following:

(1) Fabricate a placard with the words ``Do not extend the flaps

beyond the 20-degree position if ice is visible on the airplane and

ensure that the landing gear selector is down prior to landing.''

Install this placard on the airplane's instrument panel within the

pilot's clear view. Parts of the airplane where ice could

specifically be visible include the windshield wipers, center

windshield, propeller spinners, or inboard wing leading edges.

(2) Operate the airplane in accordance with BAe CAA-Mandatory

Alert Service Bulletin 27-A-JA 910340, dated March 25, 1991, Section

2.B.-Instruction for Aircraft Operations, paragraphs (1)(a) and

(1)(c) until Amendments P/32, P/49, and P/52 have been received.

Upon receipt, incorporate these amendments into Airplane Flight

Manual (AFM) HP.4.10. Ensure that Amendment G/10 is incorporated

into AFM HP.4.10.

(c) Within the next 100 hours TIS after the effective date of

this AD, incorporate the 35-degree flap modification (Amendment JA

910541) in accordance with the ACCOMPLISHMENT INSTRUCTIONS section

of Jetstream Aircraft Limited SB 27-JA 910541.

(d) The actions required by paragraphs (a) and (b) of this AD

may be terminated when the flap system is modified in accordance

with Jetstream Aircraft Limited SB 27-JA 910541.

(e) Special flight permits may be issued in accordance with

Sec. Sec. 21.197 and 21.199 of the Federal Aviation Regulations (14

CFR 21.197 and 21.199) to operate airplanes to a location where the

requirements of this AD can be accomplished.

(f) An alternative method of compliance or adjustment of the

compliance times that provides an equivalent level of safety may be

approved by the Manager, Brussels Aircraft Certification Office,

FAA, Europe, Africa, and Middle East Office, c/o American Embassy,

B-1000 Brussels, Belgium. The request should be forwarded through an

appropriate FAA Maintenance Inspector, who may add comments and then

send it to the Manager, Brussels Aircraft Certification Office.

Note 2: Information concerning the existence of approved

alternative methods of compliance with this AD, if any, may be

obtained from the Brussels Aircraft Certification Office.

(g) All persons affected by this directive may obtain copies of

the documents referred to herein upon request to Jetstream Aircraft

Limited, Manager Product Support, Prestwick Airport, Ayrshire, KA9

2RW Scotland; telephone (44-292) 79888; or Jetstream Aircraft Inc.,

Librarian, P.O. Box 16029, Dulles International Airport, Washington,

DC, 20041-6029; or may examine these documents at the FAA, Central

Region, Office of the Assistant Chief Counsel, Room 1558, 601 E.

12th Street, Kansas City, Missouri 64106.

(h) This amendment supersedes AD 91-08-01, Amendment 39-7007.

Issued in Kansas City, Missouri, on October 5, 1994.

John R. Colomy,

Acting Manager, Small Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-25289 Filed 10-12-94; 8:45 am]

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