Airworthiness Directives; SAAB Aircraft Model SAAB SF340A and SAAB 340B Airplanes

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 94-NM-46-AD; Amendment 39-8898; AD 94-09-09]

Airworthiness Directives; SAAB Aircraft Model SAAB SF340A and

SAAB 340B Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that

is applicable to certain SAAB Model SAAB SF340A and SAAB 340B

airplanes. This action requires installation of a placard in the

cockpit that informs the flight crew of the prohibition against moving

the power levers below ``flight idle'' (beta mode) when the airplane is

airborne. This amendment is prompted by an incident during which a

Model SAAB 340B airplane, that was in ``beta mode'' for a short

duration during descent, lost all engine power. The action specified in

this AD is intended to prevent engine overspeed and the resultant loss

of engine power.

DATES: Effective May 16, 1994.

The incorporation by reference of certain publications listed in

the regulations is approved by the Director of the Federal Register as

of May 16, 1994.

Comments for inclusion in the Rules Docket must be received on or

before June 28, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

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

Attention: Rules Docket No.94-NM-46-AD, 1601 Lind Avenue SW., Renton,

Washington 98055-4056. The service information referenced in this AD

may be obtained from SAAB Aircraft AB, SAAB Aircraft Product Support,

S-581 88, Linkoping, Sweden. 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: Mark Quam, Aerospace Engineer,

Standardization Branch, ANM-113, FAA, Transport Airplane Directorate,

1601 Lind Avenue SW., Renton, Washington 98055-4056; telephone (206)

227-2145; fax (206) 227-1320.

SUPPLEMENTARY INFORMATION: Recently, the FAA has received a report that

a SAAB Model SAAB 340B airplane lost all engine power during descent.

In this incident, the flight crew managed to land the airplane with no

turbine power. However, the airplane ran off the end of the runway and

sustained damage in the process. The flight data recorder from this

airplane revealed that the power levers were set below ``flight idle''

(beta mode) for approximately eight seconds during the airplane's

descent from 9,200 feet altitude. Further, the FAA has received reports

of other incidents in which operators of Model SAAB SF340A and SAAB

340B airplanes have selected ``beta mode'' either inadvertently or

intentionally during flight.

The FAA has determined that if the flight crew moves the power

levels below ``flight idle'' (beta mode) when the airplane is airborne,

the propeller will go into a low pitch angle and the propeller speed

may increase uncontrollably. This condition, if not corrected, could

result in engine overspeed and the resultant loss of engine power.

SAAB Aircraft has issued Service Bulletin 340-76-033, dated March

31, 1994, that describes procedures for installation of a placard in

the cockpit of certain Model SAAB SF340A and SAAB 340B airplanes. The

placard informs the flight crew of the prohibition against moving the

power levers below ``flight idle'' (beta mode) when the airplane is

airborne.

These airplane models are manufactured in Sweden and are type

certificated for operation in the United States under the provisions of

Section 21.29 of the Federal Aviation Regulations and the applicable

bilateral airworthiness agreement. The FAA has 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, this AD is being issued to prevent engine

overspeed and the resultant loss of engine power. This AD requires

installation of a placard in the cockpit of certain SAAB Model SAAB

SF340A and SAAB 340B airplanes. The actions are required to be

accomplished in accordance with the service bulletin described

previously.

This is considered to be interim action until final action is

identified, at which time the FAA may consider further rulemaking.

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 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 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 notice must submit a self-addressed,

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

to Docket Number 94-NM-46-AD.'' The postcard will be date stamped and

returned to the commenter.

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 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 14 CFR part

39 of the Federal Aviation Regulations 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 adding the following new

airworthiness directive:

94-09-09 SAAB Aircraft AB: Amendment 39-8898. Docket 94-NM-46-AD.

Applicability: Model SAAB SF340A airplanes having serial numbers

004 through 159, inclusive; and SAAB 340B airplanes having serial

numbers 160 through 379, inclusive; certificated in any category.

Compliance: Required as indicated, unless accomplished

previously.

To prevent engine overspeed and the resultant loss of engine

power, accomplish the following:

(a) Within 10 days after the effective date of this AD, install

a placard in the cockpit of the airplane to advise the flight crew

of the prohibition against moving the power levers below ``flight

idle'' (beta mode) when the airplane is airborne, in accordance with

Saab Service Bulletin 340-76-033, dated March 31, 1994.

(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: 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

Sec. 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 installation shall be done in accordance with Saab

Service Bulletin 340-76-033, dated March 31, 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 Saab Aircraft AB, Saab Aircraft

Product Support, S-581 88, Linkoping, Sweden. 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 May 16,1994.

Issued in Renton, Washington, on April 20, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-9990 Filed 4-28-94; 8:45 am]

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