Airworthiness Directives; Alexander Schleicher Segelflugzeugbau Model ASH 26E Sailplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-CE-06-AD]

RIN 2120-AA64

Airworthiness Directives; Alexander Schleicher Segelflugzeugbau

Model ASH 26E Sailplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to supersede Airworthiness Directive

(AD) 98-09-09, which currently requires replacing the internal cooling

air fan with a fan that incorporates a white impeller on all Alexander

Schleicher Segelflugzeugbau (Alexander Schleicher) Model ASH 26E

sailplanes. The proposed AD would require inspecting the internal

cooling air fan for damage, and replacing any fan that does not

incorporate a black impeller with a fan that incorporates a black

impeller either immediately or at a certain time period, depending on

the results of the inspection. The proposed AD is the result of

mandatory continuing airworthiness information (MCAI) issued by the

airworthiness authority for Germany. The actions specified by the

proposed AD are intended to prevent failure of the internal cooling

system air fan caused by a certain design configuration of the

impeller, which could cause the engine to overheat with possible engine

failure.

DATES: Comments must be received on or before June 8, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

Administration (FAA), Central Region, Office of the Regional Counsel,

Attention: Rules Docket No. 99-CE-06-

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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 Alexander Schleicher Segelflugzeugbau, 6416 Poppenhausen,

Wasserkuppe, Federal Republic of Germany. This information also may be

examined at the Rules Docket at the address above.

FOR FURTHER INFORMATION CONTACT: Mr. Mike Kiesov, Aerospace Engineer,

FAA, Small Airplane Directorate, 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. 99-CE-06-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 Regional Counsel, Attention:

Rules Docket No. 99-CE-06-AD, Room 1558, 601 E. 12th Street, Kansas

City, Missouri 64106.

Discussion

AD 98-09-09, Amendment 39-10489 (63 FR 20308, April 24, 1998),

currently requires replacing the internal cooling air fan with a fan

that incorporates a white impeller, part number (P/N) R1K059, on all

Alexander Schleicher Segelflugzeugbau (Alexander Schleicher) Model ASH

26E sailplanes. Accomplishment of that action is required in accordance

with Alexander Schleicher Technical Note No. 1, dated October 31, 1996;

and Mid-West Engines Ltd. Service Bulletin No. 001, dated October 5,

1996.

AD 98-09-09 was a result of a report from the Luftfahrt-Bundesamt

(LBA), which is the airworthiness authority for Germany, that the

impeller of the internal cooling air fan on the above-referenced

sailplanes could slip and result in a reduction of pressure in the

internal cooling system. The higher internal temperatures that will

follow could cause the engine to overheat with possible engine failure.

Actions Since Issuance of Previous Rule

The LBA recently notified the FAA that an unsafe condition may

exist on these Alexander Schleicher Model ASH 26E sailplanes. The LBA

advises that the internal cooling air fan installed on the affected

sailplanes as required by AD 98-09-09 incorporates a white impeller, P/

N R1K059. This type of impeller was installed in one of the affected

airplanes that had an in-flight malfunction. Research of this

malfunction reveals that the design of the white impeller is not

adequate and an improved design impeller should be installed.

This condition, if not corrected in a timely manner, could cause

the engine to overheat with possible engine failure.

Relevant Service Information

Alexander Schleicher has issued Technical Note No. 5, dated July

23, 1998, which specifies procedures for inspecting the internal

cooling air fan for damage. Mid-West Service Bulletin No. 02, dated

November 13, 1997, includes procedures for replacing any fan that does

not incorporate a black impeller, P/N R1K074, with a fan that

incorporates a P/N R1K074 impeller.

The LBA classified this service bulletin as mandatory and issued

German AD 1998-391, dated October 8, 1998, in order to assure the

continued airworthiness of these sailplanes in Germany.

The FAA's Determination

This sailplane model 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. Pursuant to this

bilateral airworthiness agreement, the LBA has kept the FAA informed of

the situation described above.

The FAA has examined the findings of the LBA; reviewed all

available information, including the service information referenced

above; and determined that AD action is necessary for products of this

type design that are certificated for operation in the United States.

Explanation of the Provisions of the Proposed AD

Since an unsafe condition has been identified that is likely to

exist or develop in other Alexander Schleicher ASH 26E sailplanes of

the same type design registered in the United States, the FAA is

proposing AD action to supersede AD 98-09-09. The proposed AD would

require inspecting the internal cooling air fan for damage, and

replacing any fan that does not incorporate a black impeller, P/N

R1K074, with a fan that incorporates a P/N R1K074 impeller. The

replacement would be accomplished either immediately or at a certain

time period, depending on the results of the inspection.

Accomplishment of the proposed action would be required in

accordance with the service information previously referenced.

Differences Between the Service Bulletin, the German AD, and This

Proposed AD

Alexander Schleicher Technical Note No. 5, dated July 23, 1998,

specifies inspecting the internal air cooling air fan prior to further

flight, and German AD 1998-391, dated October 8, 1998, requires this

inspection prior to further flight on sailplanes registered in Germany.

The FAA does not have justification to require this inspection

prior to further flight. The FAA is proposing this inspection ``within

the next 30 calendar days after the effective date of the AD.'' The FAA

is proposing the replacement ``within the next 9 calendar months after

the effective date of the AD'', or if damage is found during the

inspection, ``prior to further flight.''

Compliance Time of the Proposed AD

Although a damaged impeller blade is only unsafe while the affected

sailplanes are in flight, the condition could occur at any time. For

example, damage could occur on one sailplane with 25 hours time-in-

service (TIS)

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while not occurring on another until 250 hours TIS. This is due to

different usage levels and the various ways sailplanes are operated and

utilized. In addition, the average monthly usage of the affected

sailplane ranges throughout the fleet. For example, one owner may

operate the sailplane 25 hours TIS in one week, while another operator

may operate the sailplane 25 hours TIS in one year. In order to assure

that the unsafe condition is detected and corrected on all affected

sailplanes in a timely manner without inadvertently grounding any

affected sailplane, the FAA is proposing compliance based on calendar

time instead of hours TIS.

Cost Impact

The FAA estimates that 9 sailplanes in the U.S. registry would be

affected by the proposed AD, that it would take approximately 14

workhours per sailplane to accomplish the proposed AD, and that the

average labor rate is approximately $60 an hour. Parts are available

from the manufacturer at no cost. Based on these figures, the total

cost impact of the proposed AD on U.S. operators is estimated to be

$7,560, or $840 per sailplane.

Regulatory Impact

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. 106(g), 40113, 44701.

Sec. 39.13 [Amended]

2. Section 39.13 is amended by removing Airworthiness Directive

(AD) 98-09-09, Amendment 39-10489 (63 FR 20308, April 24, 1998), and by

adding a new airworthiness directive (AD) to read as follows:

Alexander Schleicher Segelflugzeugbau: Docket No. 99-CE-06-AD.

Applicability: Model ASH 26E sailplanes, all serial numbers,

certificated in any category; that are equipped with an internal

cooling system air fan that does not incorporate a black impeller,

part number (P/N) R1K074.

Note 1: This AD applies to each sailplane 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 sailplanes 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 in the body of this AD, unless

already accomplished.

To prevent failure of the internal cooling system air fan caused

by a certain design configuration of the impeller, which could cause

the engine to overheat with possible engine failure, accomplish the

following:

(a) Within the next 30 calendar days after the effective date of

this AD, inspect the internal cooling air fan for damage in

accordance with Alexander Schleicher Technical Note No. 5, dated

July 23, 1998.

(b) Replace the internal cooling system air fan with a fan that

incorporates a black impeller, P/N R1K074, at whichever of the

compliance times below (paragraphs (b)(1) and (b)(2) of this AD)

that applies. Accomplish this replacement in accordance with Mid-

West Service Bulletin No. 02, dated November 13, 1997:

(1) Prior to further flight if damage is found in the internal

cooling air fan during the inspection required by paragraph (a) of

this AD; or

(2) Within the next 9 calendar months after the effective date

of this AD if damage is not found during the inspection required by

paragraph (a) of this AD.

(c) As of the effective date of this AD, no person may install,

on any affected sailplane, an internal cooling system air fan that

does not incorporate a black impeller, P/N R1K074, as specified in

Mid-West Service Bulletin No. 02, dated November 13, 1997; and

Alexander Schleicher Technical Note No. 5, dated July 23, 1998.

(d) 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 sailplane to a location where

the requirements of this AD can be accomplished.

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

compliance times that provides an equivalent level of safety may be

approved by the Manager, Small Airplane Directorate, FAA, 1201

Walnut, suite 900, Kansas City, Missouri 64106. The request shall be

forwarded through an appropriate FAA Maintenance Inspector, who may

add comments and then send it to the Manager, Small Airplane

Directorate.

Note 2: Information concerning the existence of approved

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

obtained from the Small Airplane Directorate.

(f) Questions or technical information related to Alexander

Schleicher Technical Note No. 5, dated July 23, 1998, should be

directed to Alexander Schleicher Segelflugzeugbau, 6416

Poppenhausen, Wasserkuppe, Federal Republic of Germany. This service

information may be examined at the FAA, Central Region, Office of

the Regional Counsel, Room 1558, 601 E. 12th Street, Kansas City,

Missouri 64106.

Note 3: The subject of this AD is addressed in German AD 1998-

391, dated October 8, 1998.

Issued in Kansas City, Missouri, on April 19, 1999.

James E. Jackson,

Acting Manager, Small Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 99-10312 Filed 4-23-99; 8:45 am]

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