[Federal Register Volume 68, Number 73 (Wednesday, April 16, 2003)]
[Proposed Rules]
[Pages 18571-18575]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-9304]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-CE-64-AD]
RIN 2120-AA64


Airworthiness Directives; Robert E. Rust Models DeHavilland DH.C1 
Chipmunk 21, 22, and 22A Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Supplemental notice of proposed rulemaking (NPRM); Reopening of 
the comment period.

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SUMMARY: This document proposes to revise an earlier proposed 
airworthiness directive (AD) that would apply to certain Robert E. Rust 
(R.E. Rust) Models DeHavilland DH.C1 Chipmunk 21, 22, and 22A 
airplanes. The earlier NPRM would have required you to repetitively 
inspect the tailplane attachment brackets and replace each bracket. The 
earlier NPRM would have also required you to repetitively inspect each 
joint of the port and starboard engine mount frame and the rear upper 
mount frame tubes for cracks and/or damage and repair any cracks and/or 
damage found. The earlier NPRM resulted from reports of stress 
corrosion cracking found on the tailplane attachment brackets and 
fatigue cracking and chaffing of the engine mount frame. We incorrectly 
referenced replacing the tailplane attachment brackets (part number 
C1.TP.167) upon accumulating 9,984 hours time-in-service (TIS). The 
hour limitation should be 9,984 fatigue hours. Fatigue hours are hours 
TIS multiplied by the role factor (operational use) as defined in the 
manufacturer's service information. This proposed supplemental NPRM 
also adds an hour limitation for performing the repetitive inspection 
of the tailplane 1 attachment brackets. Since these actions impose an 
additional burden over that proposed in the NPRM, we are reopening the 
comment period to allow the public the chance to comment on these 
additional actions.

DATES: The Federal Aviation Administration (FAA) must receive any 
comments on this proposed rule on or before June 23, 2003.

ADDRESSES: Submit comments to FAA, Central Region, Office of the 
Regional Counsel, Attention: Rules Docket No. 2000-CE-64-AD, 901 
Locust, Room 506, Kansas City, Missouri 64106. You may view any 
comments at this location between 8 a.m. and 4 p.m., Monday through 
Friday, except Federal holidays. You may also send comments 
electronically to the following address: [email protected]. 
Comments sent electronically must contain ``Docket No. 2000-CE-64-AD'' 
in the subject line. If you send comments electronically as attached 
electronic files, the files must be formatted in Microsoft Work 97 for 
Windows or ASCII text.
    You may get service information that applies to this proposed AD 
from DeHavilland Support Limited, Duxford Airfield, Bldg. 213, 
Cambridgeshire, CB2 4QR, United Kingdom, telephone: +44 1223 830090, 
facsimile: +44 1223 830085, e-mail: [email protected]. You may also 
view this information at the Rules Docket at the address above.

FOR FURTHER INFORMATION CONTACT: Cindy Lorenzen, Aerospace Engineer, 
FAA, Atlanta Aircraft Certification Office, 1895 Phoenix Boulevard, 
Suite 450, Atlanta, Georgia; telephone: (770) 703-6078; facsimile: 
(770) 703-6097.

SUPPLEMENTARY INFORMATION:

Comments Invited

How Do I Comment on This Proposed AD?

    The FAA invites comments on this proposed rule. You may submit 
whatever written data, views, or arguments you choose. You need to 
include the rule's docket number and submit your comments to the 
address specified under the caption ADDRESSES. We will consider all 
comments received on or before the closing date. We may amend this 
proposed rule in light of comments received. Factual information that 
supports your ideas and suggestions is extremely helpful in evaluating 
the effectiveness of this proposed AD action and determining whether we 
need to take additional rulemaking action.

Are There Any Specific Portions of This Proposed AD I Should Pay 
Attention to?

    The FAA specifically invites comments on the overall regulatory, 
economic, environmental, and energy aspects of this proposed rule that 
might suggest a need to modify the rule. You may view all comments we 
receive before and after the closing date of the rule in the Rules 
Docket. We will file a report in the Rules Docket that

[[Page 18572]]

summarizes each contact we have with the public that concerns the 
substantive parts of this proposed AD.

How Can I Be Sure FAA Receives My Comment?

    If you want FAA to acknowledge the receipt of your mailed comments, 
you must include a self-addressed, stamped postcard. On the postcard, 
write ``Comments to Docket No. 2000-CE-64-AD.'' We will date stamp and 
mail the postcard back to you.

Discussion

What Events Have Caused Us To Issue the Earlier NPRM?

    We received reports that an unsafe condition exists on certain R.E. 
Rust Models DeHavilland DH.C1 Chipmunk 21, 22, and 22A airplanes. After 
reviewing several of these airplanes, stress corrosion cracking was 
found on the tailplane attachment brackets and fatigue cracks and 
chaffing were found on the engine mount frame.
    Cracks in the engine mount frame were found in the area of the 
junction of the front and rear top tube and engine mounting foot 
support brackets and in the front of the frame. We have determined that 
fatigue is the cause of the cracks. The upper aft mount frame tubes 
were also found to have damage caused by chaffing by the cowling 
support rod.

What Are the Consequences if the Condition Is Not Corrected?

    These conditions, if not corrected, could result in failure of the 
tailplane attachment brackets and failure of the engine mount. Such 
failures could lead to loss of control of the airplane.

Has FAA Taken Any Action to This Point?

    We issued a proposal to amend part 39 of the Federal Aviation 
Regulations (14 CFR part 39) to include an AD that would apply to 
certain R.E. Rust Models DeHavilland DH.C1 Chipmunk 21, 22, and 22A 
airplanes. This proposal was published in the Federal Register as a 
notice of proposed rulemaking (NPRM) on November 12, 2002 (67 FR 
68536). The NPRM proposed to require you to repetitively inspect the 
tailplane attachment brackets and replace each bracket. The NPRM also 
proposed to require you to repetitively inspect each joint of the port 
and starboard engine mount frame and the rear upper mount frame tubes 
for cracks and/or damage and repair any cracks and/or damage found.

Was the Public Invited To Comment?

    The FAA encouraged interested persons to participate in the making 
of this amendment. The following presents the comments received on the 
proposal and FAA's response to each comment:

Comment Issue No. 1: Change the Compliance Time for Replacing the 
Tailplane Attachment Brackets

What Is the Commenter's Concern?

    The commenter states that replacement parts for the tailplane 
attachment brackets may not be available from the manufacturer within 
90 days after the effective date of this AD. Therefore, the commenter 
suggests allowing more time to acquire parts by changing the compliance 
time for replacing the tailplane attachment brackets if cracks are 
found during the initial inspection from 90 days to 12 months after the 
effective date of this AD.

What Is FAA's Response to the Concern?

    The commenter does not offer any solution to ensure the 
airworthiness of the airplanes until the parts become available. We 
cannot increase the compliance time unless other means to ensure the 
continued airworthiness of these airplanes are substantiated.
    We will consider an alternative method of compliance if the 
alternative provides an equivalent level of safety as outlined in 
paragraph (e) of this AD.
    We are not changing the final rule AD action based on this comment.

Comment Issue No. 2: Change the Compliance Time for the Repetitive 
Inspections of the Tailplane Attachment Brackets

What Is the Commenter's Concern?

    The commenter suggests that the repetitive inspections of the 
tailplane attachment brackets should be changed to every 150 fatigue 
hour or 6 months, whichever comes first, in order to ensure the 
airworthiness of these airplanes. The NPRM only proposed inspections 
every 6 months.

What Is FAA's Response to the Concern?

    We concur with the commenter. Requiring repetitive inspections at 
every 150 fatigue hours or 6 months, whichever comes first, will ensure 
that the unsafe condition will not go undetected on high usage 
airplanes for a long period of time and will ensure the airworthiness 
of the affected airplanes.
    We will make this change. Fatigue hours are hours TIS multiplied by 
the role factor (operational use) as specified in British Aerospace 
Mandatory Technical News Sheet Series: Chipmunk (C1), No. 138, Issue: 
5, dated August 1, 1985. Because adding the fatigue hours requirement 
to the repetitive inspection compliance time could increase the burden 
upon the public, we will reopen the comment period and issue a 
supplemental NPRM.

Comment Issue No. 3: Remove the Grace Period Allowed Beyond the Safe 
Life Limit for Replacing the Tailplane Attachment Brackets

What Is the Commenter's Concern?

    The commenter states that the ultimate safe life limit of 9,984 
fatigue hours for part number C1.TP.167 is a never exceed life and 
cannot be extended. Once an airplane has reached this safe life limit, 
the tailplane attachment bracket must be replaced before further 
flight.

What Is FAA's Response to the Concern?

    We concur that a life limit is a never exceed limit. However, the 
safe life limit for the tailplane attachment bracket has not previously 
been established and enforced for the owners/operators of the affected 
airplanes. The life limit was not part of the type certificate data and 
was not previously mandated by an AD. Part of this proposed AD is 
establishing the safe life limit for this part. Removing the 90 day 
grace period for these airplanes already over or nearing 9,984 fatigue 
hours on the tailplane attachment bracket could inadvertently ground 
these airplanes when the AD becomes effective.
    We are not changing the final rule AD action based on this comment.

The Supplemental NPRM

What Events Have Caused FAA To Issue a Supplemental NPRM?

    In addition to adding the fatigue hour requirement to the 
repetitive inspection compliance time, we are correcting reference to 
the life limit as 9,984 fatigue hours instead of 9,984 hours TIS. 
Fatigue hours are hours TIS multiplied by the role factor (operational 
use).

How Will the Changes to the NPRM Impact the Public?

    Proposing to change the intervals for performing the repetitive 
inspections of the tailplane attachment brackets to include an hour 
limitation and changing hours TIS to fatigue hours go beyond the scope 
of what was already proposed. Therefore, we are issuing a supplemental 
NPRM and reopening the comment period to allow the public additional 
time to comment on the proposed AD.

[[Page 18573]]

How Does the Revision to 14 CFR Part 39 Affect This Proposed AD?

    On July 10, 2002, FAA published a new version of 14 CFR part 39 (67 
FR 47997, July 22, 2002), which governs FAA's AD system. This 
regulation now includes material that relate to special flight permits, 
alternative methods of compliance, and altered products. This material 
previously was included in each individual AD. Since this material is 
included in 14 CFR part 39, we will not include it in future AD 
actions.

Cost Impact

How Many Airplanes Would This Proposed AD Impact?

    We estimate that this proposed AD affects 54 airplanes in the U.S. 
registry.

What Would Be the Cost Impact of This Proposed AD on Owners/Operators 
of the Affected Airplanes?

    We estimate the following costs to accomplish the proposed 
inspections of the tailplane attachment brackets:

------------------------------------------------------------------------
                                                 Total cost   Total cost
          Labor cost              Parts cost        per        on U.S.
                                                  airplane    operators
------------------------------------------------------------------------
32 workhours x $60 per hour =  No parts              $1,920  $1,920 x 54
 $1,920.                        required.                    = $103,680.
------------------------------------------------------------------------

    We estimate the following costs to accomplish any necessary 
replacements that would be required based on the results of the 
proposed inspection. We have no way of determining the number of 
airplanes that may need such replacement:

------------------------------------------------------------------------
                                                            Total cost
            Labor cost                    Parts cost           per
                                                             airplane
-----------------------------------------------------------------------
3 workhours x $60 per hour = $180   $600 per bracket (2    $180 + $600
 per bracket.                        brackets per              = $780.
                                     airplane).
------------------------------------------------------------------------

    We estimate the following costs to accomplish the proposed 
inspections of the engine mount frame:

------------------------------------------------------------------------
                                                 Total cost   Total cost
          Labor cost              Parts cost        per        on U.S.
                                                  airplane    operators
------------------------------------------------------------------------
16 workhours x $60 per hour =  No parts                $960  $960 x 54 =
 $960.                          required.                       $51,840.
------------------------------------------------------------------------

    The FAA has no method of determining the number of repairs or 
replacements each owner/operator would incur over the life of each of 
the affected airplanes based on the results of the proposed 
inspections. We have no way of determining the number of airplanes that 
may need such repair. The extent of damage may vary on each airplane.

Compliance Time of This Proposed AD

What Would Be the Compliance Time of This Proposed AD?

    The compliance time for the initial inspection proposed in this AD 
is ``within the next 90 days after the effective date of this AD.''

Why Is the Proposed Compliance Time Presented in Calendar Time Instead 
of Hours Time-in-Service (TIS)?

    An unsafe condition specified by this proposed AD is caused by 
corrosion. Corrosion can occur regardless of whether the aircraft is in 
operation or is in storage. Therefore, to assure that the unsafe 
condition specified in the proposed AD does not go undetected for a 
long period of time, the compliance is presented in calendar time 
instead of TIS.

Regulatory Impact

Would This Proposed AD Impact Various Entities?

    The regulations proposed herein would not have a substantial direct 
effect 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, it 
is determined that this proposed rule would not have federalism 
implications under Executive Order 13132.

Would This Proposed AD Involve a Significant Rule or Regulatory Action?

    For the reasons discussed above, I certify that this proposed 
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, under 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:

[[Page 18574]]

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. FAA amends Sec.  39.13 by adding a new airworthiness directive 
(AD) to read as follows:

Robert E. Rust: Docket No. 2000-CE-64-AD

    (a) What airplanes are affected by this AD? This AD affects R.E. 
Rust Models DeHavilland DH.C1 Chipmunk 21, 22, and 22A airplanes, 
serial numbers C1-001 through C1-1014, that are type certificated in 
any category.

    Note 1: We recommend all owners/operators of DeHavilland DH.C1 
Chipmunk 21, 22, and 22A airplanes, serial numbers C1-001 through 
C1-1014, with experimental airworthiness certificates comply with 
the actions required in this AD.

    (b) Who must comply with this AD? Anyone who wishes to operate 
any of the above airplanes must comply with this AD.
    (c) What problem does this AD address? The actions specified by 
this AD are intended to prevent failure of the tailplane attachment 
brackets caused by stress corrosion cracking and failure of the 
engine mount, which could result in loss of the tail section and 
separation of the engine from the airplane respectively. Such 
failures could lead to loss of control of the airplane.
    (d) What actions must I accomplish to address this problem? To 
address this problem, you must accomplish the following:
    (1) Tailplane Attachment Brackets

------------------------------------------------------------------------
             Compliance                   Actions          Procedures
------------------------------------------------------------------------
(i) Initially inspect within the     Inspect, using     In accordance
 next 90 days after the effective     dye penetrant,     with British
 date of this AD.                     the tailplane      Aerospace
(A) Inspect thereafter at intervals   attachment         Military
 not to exceed 6 months or 150        brackets, part-    Aircraft and
 fatigue hours, whichever occurs      number (P/N)       Aerostructures
 first, until the modification        C1.TP.167 (or      (BAe Aircraft)
 required by paragraph (d)(1)(ii)     FAA-approved       Mandatory
 of this AD is incorporated.          equivalent part)   Technical News
(B) When the modification required    for cracks.        Sheet CT (C1)
 by paragraph (d)(1)(ii) is                              No. 176, Issue
 incorporated, you may terminate                         2, dated
 the repetitive inspections of the                       November 1,
 tailplane attachment brackets.                          1997; and Civil
                                                         Modification
                                                         Mandatory
                                                         Modification
                                                         No. Chipmunk
                                                         H357, dated
                                                         March 12, 1984.
                                                         Calculate
                                                         fatigue hours
                                                         by multiplying
                                                         the TIS by the
                                                         role factor in
                                                         accordance with
                                                         British
                                                         Aerospace
                                                         Mandatory
                                                         Technical News
                                                         Sheet Series:
                                                         Chipmunk (C1),
                                                         No. 138, Issue:
                                                         5, dated August
                                                         1, 1985.
------------------------------------
(ii) At whichever of the following   Replace the        In accordance
 that occurs first:                   tailplane          with British
(A) Prior to further flight after     attachment         Aerospace
 the inspection where any crack is    bracket by         Military
 found; or                            incorporating      Aircraft and
(B) Upon accumulating 9,984 fatigue   Modification       Aerostructures
 hours or within the next 90 days     H357 (P/N          (BAe Aircraft)
 after the effective date of this     C1.TP.313) or      Mandatory
 AD, whichever occurs later           FAA-approved       Technical News
                                      equivalent part    Sheet CT (C1)
                                      number.            No. 176, Issue
                                      Installing P/N     2, dated
                                      C1.TP.313 (or      November 1,
                                      FAA-approved       1997; and Civil
                                      equivalent part    Modification
                                      number)            Mandatory
                                      terminates the     Modification
                                      repetitive         No. Chipmunk
                                      inspection         H357, dated
                                      requirement of     March 12, 1984.
                                      the tailplane      Calculate
                                      attachment         fatigue hours
                                      brackets.          by multiplying
                                                         the TIS by the
                                                         role factor in
                                                         accordance with
                                                         British
                                                         Aerospace
                                                         Mandatory
                                                         Technical News
                                                         Sheet Series:
                                                         Chipmunk (C1),
                                                         No. 138, Issue:
                                                         5, dated August
                                                         1, 1985.
(iii) As of the effective date of    Only install a     Not applicable.
 this AD                              tailplane
                                      attachment
                                      bracket that is
                                      P/N C1.TP.313.
                                      or FAA-approved
                                      equivalent part
                                      number.
(iv) As of the effective date of     Incorporate the    In accordance
 this AD                              following into     with British
                                      the Aircraft       Aerospace
                                      Logbook: ``In      Military
                                      accordance with    Aircraft and
                                      AD **-**-**, the   Aerostructures
                                      tailplane          (BAe Aircraft)
                                      attachment         Mandatory
                                      bracket is life    Technical News
                                      limited to 9,984   Sheet CT (C1)
                                      fatigue hours.''.  No. 176, Issue
                                                         2, dated
                                                         November 1,
                                                         1997.
------------------------------------------------------------------------

    (2) Engine Mount Frames

------------------------------------------------------------------------
             Actions                  Compliance          Procedures
------------------------------------------------------------------------
(i) Inspect each joint of the     Initially inspect   In accordance with
 port and starboard engine mount   within the next     British Aerospace
 frame and the rear upper mount    90 days after the   Aerostructures
 frame tubes for cracks and/or     effective date of   Limited (BAe
 damage.                           this AD.            Aircraft)
                                   Repetitively        Mandatory
                                   inspect             Technical News
                                   thereafter at       Sheet CT (C1) No.
                                   intervals not to    190, Issue 2,
                                   exceed 600 hours    dated April 1,
                                   TIS.                1995.
---------------------------------

[[Page 18575]]

 
(ii) If cracks and/or damage is   Prior to further    Repair in
 found during any inspection       flight after the    accordance with
 required in paragraph (d)(2)(i)   inspection in       AC 43.13-1B,
 of this AD.                       which any crack     Change 1, dated
(A) obtain a repair scheme from    and/or damage is    September 27,
 the manufacturer through the      found.              2001, Chapter 4,
 FAA at the address specified in   Repetitively        Paragraph 4-99 or
 paragraph (f) of this AD and      inspect as          in accordance
 incorporate this repair scheme,   required in         with the repair
 or repair in accordance with      paragraph           scheme obtained
 FAA Advisory Circular (AC)        (d)(2)(i) of this   from DeHavilland
 43.13-1B, Change 1, dated         AD.                 Support Limited,
 September 27, 2001, Chapter 4,                        Duxford Airfield,
 Paragraph 4-99; or.                                   Bldg. 213,
(B) replace with a new or                              Cambridgeshire,
 serviceable part.                                     CB2 4QR, United
                                                       Kingdom. Obtain
                                                       this repair
                                                       scheme through
                                                       the FAA at the
                                                       address specified
                                                       in paragraph (f)
                                                       of this AD.
                                                       Replace in
                                                       accordance with
                                                       British Aerospace
                                                       Aerostructures
                                                       Limited (BAe
                                                       Aircraft)
                                                       Mandatory
                                                       Technical News
                                                       Sheet CT (C1) No.
                                                       190, Issue 2,
                                                       dated April 1,
                                                       1995, or AC 43.13-
                                                       1B, Change 1,
                                                       dated September
                                                       27, 2001, Chapter
                                                       4, Paragraph 4-
                                                       99.
---------------------------------
(iii) Bind the rear upper mount   Prior to further    In accordance with
 frame tubes with a high density   flight after the    British Aerospace
 polythene tape at the location    initial             Aerostructures
 where the cowling support rod     inspection          Limited (BAe
 clip is secured.                  required in         Aircraft)
                                   paragraph (d)(1)    Mandatory
                                   of this AD.         Technical News
                                                       Sheet CT (C1) No.
                                                       190, Issue 2,
                                                       dated April 1,
                                                       1995.
------------------------------------------------------------------------

    (e) Can I comply with this AD in any other way? To use an 
alternative method of compliance or adjust the compliance time, 
follow the procedures in 14 CFR 39.13. Send these requests to the 
Manager, Atlanta Aircraft Certification Office (ACO). Contact Cindy 
Lorenzen, Aerospace Engineer, FAA, Atlanta Aircraft Certification 
Office, 1895 Phoenix Boulevard, Suite 450, Atlanta, Georgia; 
telephone: (770) 703-6078; facsimile: (770) 703-6097.
    (f) How do I get copies of the documents referenced in this AD? 
You may get copies of the documents referenced in this AD from 
DeHavilland Support Limited, Duxford Airfield, Bldg. 213, 
Cambridgeshire, CB2 4QR, United Kingdom, telephone: +44 1223 830090, 
facsimile: +44 1223 830085, e-mail: [email protected]. You may view 
these documents at FAA, Central Region, Office of the Regional 
Counsel, 901 Locust, Room 506, Kansas City, Missouri 64106.

    Issued in Kansas City, Missouri, on April 10, 2003.
Dorenda D. Baker,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 03-9304 Filed 4-15-03; 8:45 am]
BILLING CODE 4910-13-P