Airworthiness Directives; Alexander Schleicher Models ASW-12, ASW-15, ASW-15B, and ASW-17 Gliders

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 91-CE-40-AD]

Airworthiness Directives; Alexander Schleicher Models ASW-12,

ASW-15, ASW-15B, and ASW-17 Gliders

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: This document proposes to supersede AD 88-11-05, which

currently requires repetitively inspecting the wing spar of Alexander

Schleicher Models ASW-15 and ASW-15B gliders for wood rot, and

replacing any wing spar where wood rot is found. Alexander Schleicher

Models ASW-12 and ASW-17 gliders are of a similar type design of the

models affected by the current AD, and the Federal Aviation

Administration (FAA), in working with the Civil Aviation Authority of

Germany, has decided that the actions referenced in AD 88-11-05 should

also apply to these glider models. The actions specified by the

proposed AD are intended to prevent failure of the wing spar caused by

wood rot, which, if not detected and corrected, could result in loss of

control of the glider.

DATES: Comments must be received on or before February 24, 1995.

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

Office of the Assistant Chief Counsel, Attention: Rules Docket No. 91-

CE-40-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 GmbH & Company, D-36163, Poppenhausen-

Wasserkuppe, Germany; or Eastern Sailplane, Heath Stage Route Shelburne

Falls, Massachusetts 01370; telephone (413) 625-6059. This information

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

FOR FURTHER INFORMATION CONTACT: Mr. Herman Belderok, Project Officer,

Small Airplane Directorate, Aircraft 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. 91-CE-40-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. 91-CE-40-AD, Room 1558, 601 E. 12th Street,

Kansas City, Missouri 64106.

Discussion

A report of an in-flight wing failure because of box spar wood rot

on a Model ASW-15 glider that was certificated for operation in

Australia prompted the FAA to issue AD 88-11-05, Amendment 39-5997.

This AD requires repetitively inspecting the wing spar for wood rot on

Alexander Schleicher Models ASW-15 and ASW-15B gliders that are

certificated for operation in the United States, and replacing any wood

wing spar where wood rot is found. These actions are accomplished in

accordance with Alexander Schleicher ASW-15 Technical Note (TN) No. 23,

dated April 21, 1988.

The wing configuration of these gliders includes a wood box wing

spar. Water can penetrate the box spar interior, which permits the

growth of wood destroying mold fungus. This fungus could destroy the

balsa wood spar webs and plywood blocks of the spar to the point where

the residual spar strength would no longer be sufficient.

The Luftfahrt-Bundesamt (LBA), which is the airworthiness authority

for Germany, recently notified the FAA that Alexander Schleicher Models

ASW-12 and ASW-17 gliders contain a similar wing configuration. The LBA

advises that, if periodic inspections are not accomplished on the wing

spar of the referenced gliders, then wood rot could occur. This

condition, if not detected and corrected, could result in failure of

the wing spar and subsequent loss of control of the glider.

Alexander Schleicher has issued ASW-12 TN No. 4, dated May 10,

1989, and ASW-17 TN No. 12, dated May 8, 1989, which specify procedures

for repetitively inspecting the wing spar on the Models ASW-12 and ASW-

17 gliders.

This airplane 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, 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 in other Alexander Schleicher Models ASW-12, ASW-15,

ASW-15B, and ASW-17 gliders of the same type design, the proposed AD

would supersede AD 88-11-05, Amendment 39-5997, with a new AD that

would (1) retain the requirement of repetitively inspecting the wing

spar for wood rot on the Models ASW-15 and ASW-15B gliders, and

replacing the wing spar if wood rot is found; and (2) extend these

repetitive inspections and possible replacement to Models ASW-12 and

ASW-17 gliders. The proposed inspections would be accomplished in

accordance with either Alexander Schleicher ASW-15 TN No. 23, dated

April 21, 1988; Alexander Schleicher ASW-12 TN No. 4, dated May 10,

1989; or Alexander Schleicher ASW-17 TN No. 12, dated May 8, 1989, as

applicable.

The compliance time presented in the proposed AD is based upon

calendar time instead of hours time-in-service. Rotting of the wood

wing box spar is caused by moisture and the condition could exist or

develop regardless of whether the glider is in actual operation. For

this reason, the FAA has determined that the compliance time of the

proposed AD action should be in calendar time.

The FAA estimates that 50 gliders (7 ASW-12's, 27 ASW-15's, 6 ASW-

15B's, and 10 ASW-17's) in the U.S. registry would be affected by the

proposed AD, that it would take approximately 6 workhours to accomplish

the proposed action, and that the average labor rate is approximately

$60 an hour. Parts cost approximately $110 per glider, and the proposed

core analysis would cost $185. Based on these figures, the total cost

impact of the proposed AD on U.S. operators is estimated to be $32,750.

This figure is based upon the assumption that no affected glider owner/

operator has accomplished the proposed inspection, nor does it account

for repetitive inspections. The FAA has no way of determining the

number of repetitive inspections an owner/operator may incur.

In addition, AD 88-11-05 required the same actions as is proposed

on 33 airplanes. With this in mind, the cost impact of the proposed AD

upon U.S. operators is reduced $21,615 from $32,750 to $11,135.

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 88-11-05, Amendment 39-

5997, and by adding a new airworthiness directive to read as follows:

Alexander Schleicher: Docket No. 91-CE-40-AD; Supersedes AD 88-11-

05, Amendment 39-5997.

Applicability: Models ASW-12, ASW-15, ASW-15B, and ASW-17

gliders (all serial numbers), certificated in any category.

Compliance: Required initially as follows, and thereafter as

indicated in the body of this AD:

1. For Models ASW-12 and ASW-17: Within the next 6 calendar

months after the effective date of this AD, unless already

accomplished.

2. For Models ASW-15 and ASW-15B: On or before the last day of

the 12th calendar month after the last inspection required by AD 88-

11-05, Amendment 39-5997.

To prevent failure of the wing spar caused by wood rot, which,

if not detected and corrected, could result in loss of control of

the glider, accomplish the following:

(a) Visually inspect the wing spar for wood rot in accordance

with either Action Paragraphs 1.1 through 1.3 of Alexander

Schleicher ASW-12 Technical Note (TN) No. 4, dated May 10, 1989;

Action Paragraphs 1.1, 1.2, and 2.1 of Alexander Schleicher ASW-15

TN No. 23, dated April 21, 1988; or Action Paragraphs 1.1 and 1.2 of

Alexander Schleicher ASW-17 TN No. 12, dated May 8, 1989, as

applicable.

(b) Mark and send wood cores obtained through the inspection

specified in paragraph (a) to a mycology laboratory for

microscopical inspection for heavy wood destroying fungal

infestation in accordance with either Action Paragraph 1.3 of

Alexander Schleicher ASW-12 TN No. 4, dated May 10, 1989; Action

Paragraph 2.1 of Alexander Schleicher ASW-15 TN No. 23, dated April

21, 1988; or Action Paragraph 1.2 of Alexander Schleicher ASW-17 TN

No. 12, dated May 8, 1989, as applicable.

(c) If moisture damage, swelling, evidence that water has

penetrated into the spar fork, or fungal infestation is found, prior

to further flight after the inspection required by paragraph (a) of

this AD, accomplish the following:

(1) Wait for the results of the microscopical examination and

then obtain a repair scheme from the manufacturer through the

Manager, Small Airplane Directorate, at the address specified in

paragraph (g) of this AD, and incorporate this repair scheme.

(2) Apply preservative, strengthen the inspection hole area, and

close the hole in accordance with either Action Paragraph 1.4 of

Alexander Schleicher ASW-12 TN No. 4, dated May 10, 1989; Action

Paragraph 2.2 of Alexander Schleicher ASW-15 TN No. 23, dated April

21, 1988; or Action Paragraph 1.3 of Alexander Schleicher ASW-17 TN

No. 12, dated May 8, 1989, as applicable.

(d) If no moisture damage, swelling, evidence that water has

penetrated into the spar fork, or fungal infestation is found,

accomplish the following:

(1) Prior to further flight after the inspection required by

paragraph (a) of this AD, apply preservative, strengthen the

inspection hole area, and close the hole in accordance with either

Action Paragraph 1.4 of Alexander Schleicher ASW-12 TN No. 4, dated

May 10, 1989; Action Paragraph 2.2 of Alexander Schleicher ASW-15 TN

No. 23, dated April 21, 1988; or Action Paragraph 1.3 of Alexander

Schleicher ASW-17 TN No. 12, dated May 8, 1989, as applicable.

(2) The airplane may be operated during the microscopical

examination of the wood core. However, if these examination results

reveal heavy wood destroying fungal infestation, prior to further

flight after receiving the results, obtain a repair scheme from the

manufacturer through the Manager, Small Airplane Directorate, at the

address specified in paragraph (g) of this AD, and incorporate this

repair scheme.

(e) The inspection requirements specified in paragraphs (a)

through (c) of this AD, excluding the wood core microscopical

examination requirements, shall be accomplished annually on or

before the last day of the 12th calendar month after the last

inspection.

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

Secs. 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.

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

initial or repetitive compliance times that provides an equivalent

level of safety may be approved by the Manager, Small Airplane

Directorate, Aircraft Certification Service, 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: Information concerning the existence of approved

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

obtained from the Small Airplane Directorate.

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

the document referred to herein upon request to Alexander Schleicher

GmbH & Company, D-36163, Poppenhausen-Wasserkuppe, Germany; or

Eastern Sailplane, Heath Stage Route Shelburne Falls, Massachusetts

01370; or may examine this document at the FAA, Central Region,

Office of the Assistant Chief Counsel, Room 1558, 601 E. 12th

Street, Kansas City, Missouri 64106.

(i) This amendment supersedes AD 88-11-05, Amendment 39-5997.

Issued in Kansas City, Missouri, on December 13, 1994.

Barry D. Clements,

Manager, Small Airplane Directorate, Aircraft Certification Service.

[FR Doc. 94-31062 Filed 12-16-94; 8:45 am]

BILLING CODE 4910-13-U