[Federal Register Volume 59, Number 180 (Monday, September 19, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-23078]


[[Page Unknown]]

[Federal Register: September 19, 1994]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 91-CE-83-AD; Amendment 39-9024; AD 91-25-08 R1]

 

Airworthiness Directives; Cessna Aircraft Company Models 421C and 
425 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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

SUMMARY: This amendment revises Airworthiness Directive (AD) 91-25-08, 
which currently requires repetitively inspecting both wing front spar 
upper caps for cracks on certain Cessna Aircraft Company (Cessna) 
Models 421C and 425 airplanes, and repairing cracks that exceed certain 
limits. This action provides the option of incorporating a certain wing 
spar upper cap service kit as either terminating action or as an 
extension to the repetitive inspections currently required. Wing front 
spar upper cap cracks at the main landing gear actuating cylinder 
attachment fitting on three of the affected airplanes prompted this 
action. The actions specified by this AD are intended to prevent wing 
failure caused by excessive wing spar cracking.

DATES: Effective November 4, 1994.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of November 4, 1994.

ADDRESSES: Service information that applies to this AD may be obtained 
from the Cessna Aircraft Company, Customer Services, P.O. Box 1521, 
Wichita, Kansas 67201. This information may also be examined at the 
Federal Aviation Administration (FAA), Central Region, Office of the 
Assistant Chief Counsel, Room 1558, 601 E. 12th Street, Kansas City, 
Missouri 64106; or at the Office of the Federal Register, 800 North 
Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Mr. Larry Abbott, Aerospace Engineer, 
FAA, Wichita Aircraft Certification Office, 1801 Airport Road, Room 
100, Wichita, Kansas 67209; telephone (316) 946-4123; facsimile (316) 
946-4407.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an AD that would apply 
to certain Cessna Models 421C and 425 airplanes was published in the 
Federal Register on April 20, 1994 (59 FR 18768). The action proposed 
to revise AD 91-25-08 by maintaining the wing front spar upper cap 
repetitive inspection and possible crack repair requirement, and adding 
the option of incorporating the applicable Cessna service kits to 
either eliminate or extend the inspection time interval (depending on 
whether cracks are found) of the repetitive inspections. The proposed 
inspections would be accomplished in accordance with the ACCOMPLISHMENT 
INSTRUCTIONS section of ATTACHMENT TO SERVICE BULLETIN (SB) to Cessna 
SB CQB91-8R1, or the ACCOMPLISHMENT INSTRUCTIONS attachment to Cessna 
SB MEB91-7R1, as applicable. The proposed inspection-extending or 
inspection-terminating modifications (optional) would be accomplished 
in accordance with the instructions to the applicable service kits that 
are included as an attachment to the above-referenced service 
bulletins.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the one comment received.
    The commenter states that, although the proposal does not apply to 
the serial number airplanes that the commenter owns, all 16 hi-lock 
pins of each aft main landing gear support (part number 5122724-1 and 
5122724-2) were found loose during an annual inspection. The commenter 
believes that the above-referenced main landing gear supports are 
located in the same general area as the area referenced in the 
proposal, and that these areas share the same structural loads. For 
these reasons, the commenter proposes expanding the rule to include an 
inspection of these main landing gear supports as well as the wing 
front spar upper caps. The FAA concurs that the referenced main landing 
gear supports are in the same general area as the wing front spar upper 
caps (between the main landing gear actuating cylinder attachment and 
the front spar wing attach fittings); however, the two do not share the 
same structural loads. The main landing gear supports incur loads from 
the landing gear while the upper spar caps incur loads from the gear 
retraction cylinder. This AD is written only to detect and correct wing 
front spar upper cap cracking because the FAA identified this as an 
unsafe condition that needed AD corrective action. The FAA will 
evaluate service difficulty reports on the main landing gear supports, 
and, if found necessary, will initiate applicable rulemaking at that 
time. The AD is unchanged as a result of this comment.
    After careful review of all available information including the 
comment referenced above, the FAA has determined that air safety and 
the public interest require the adoption of the rule as proposed except 
for minor editorial corrections. The FAA has determined that these 
minor corrections will not change the meaning of the AD nor add any 
additional burden upon the public than was already proposed.
    The FAA estimates that 551 airplanes in the U.S. registry will be 
affected by this AD, that it will take approximately 3 workhours per 
airplane to accomplish the required action, and that the average labor 
rate is approximately $55 an hour. Based on these figures, the total 
cost impact of the AD on U.S. operators is estimated to be $90,915. 
This figure does not take into account the cost of repetitive 
inspections nor the cost of the optional inspection-extending or 
inspection-terminating service kit installations. The FAA has no way of 
determining how many repetitive inspections each operator would incur 
over the lifetime of the airplane.
    In addition, the FAA estimates 52 workhours to install service kits 
on the spar caps at an average labor rate of approximately $55 an hour, 
and $1,050 cost per airplane for service kit parts. Based on these 
figures, the cost for the optional service kit installations on U.S. 
operators would be $2,154,410 or $3,910 per airplane. After 
incorporation of these kits, the repetitive inspections would be 
terminated or the number of repetitive inspections would be reduced 
depending on whether the spar was cracked.
    The Cessna Aircraft Company has informed the FAA that 67 SK421-142  
(-1 or -2) or SK425-44 (-1 or -2) service kits have been sold, thus 
reducing or terminating the inspections for the particular airplane 
wing front spar upper cap that the kit is installed on. Repetitive 
inspections are no longer required on the airplane if both wing front 
spar upper caps have service kits incorporated, and these kits are 
incorporated without cracks present. The FAA has no reasonably 
available means of finding out how many inspection reductions (kit 
incorporated with cracks) and how many inspection terminations (kit 
incorporated without cracks) are involved, or how many airplanes 
incorporated a left wing kit  (-1) and a right wing kit (-2). With this 
in mind, the FAA does not know exactly how much this reduces the cost 
of the inspections and optional modification portion of this AD on U.S. 
operators; however, the FAA would estimate this cost reduction at 
around $125,000, thus reducing the optional modification portion of 
this AD from a fleetwide cost impact of $2,154,410 to $2,029,410. This 
estimate is based on taking the average workhour per wing of 26 
workhours (2 wings = 52 workhours) times the average labor rate of $55 
per hour plus the average cost of the different kits.
    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.
    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) 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 final evaluation prepared for this 
action is contained 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, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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 91-25-08, Amendment 39-
8109 (56 FR 60056, November 27, 1991), and by adding a new 
airworthiness directive to read as follows:

91-25-08 R1 Cessna Aircraft Company: Amendment 39-9024; Docket No. 
91-CE-83-AD; Revises AD 91-25-08, Amendment 39-8109.

    Applicability: The following model and serial number airplanes, 
certificated in any category: 

------------------------------------------------------------------------
      Model                             Serial Nos.                     
------------------------------------------------------------------------
421C............  421C0801 through 421C1807.                            
425.............  425-0002 through 425-0236.                            
------------------------------------------------------------------------

    Compliance: Required initially upon the accumulation of 3,000 
hours time-in-service (TIS) or within the next 50 hours TIS after 
the effective date of this AD, whichever occurs later, unless 
already accomplished within the last 300 hours TIS, and thereafter 
as indicated in the body of this AD.

    Note 1: The compliance times specified in this AD take 
precedence over those referenced in the applicable service 
information.

    To prevent wing failure caused by excessive wing spar cracking, 
accomplish the following:
    (a) Fluorescent penetrant inspect both the left and right wing 
front spar upper caps for cracks between the main landing gear 
actuating cylinder attachment and the front spar wing attach 
fittings in accordance with the ACCOMPLISHMENT INSTRUCTIONS section 
of ATTACHMENT TO SERVICE BULLETIN (SB) to Cessna SB CQB91-8R1, or 
the ACCOMPLISHMENT INSTRUCTIONS attachment to Cessna SB MEB91-7R1, 
as applicable.
    (b) If any crack is found that is parallel (inboard--outboard) 
to the top of the spar cap, install the applicable SK421-142 or 
SK425-44 service kit (-1 for left spar cap and -2 for right spar 
cap) in accordance with instructions to the applicable service kit 
(included with the service bulletins referenced in paragraph (a) of 
this AD) at the times that correspond with the following crack 
lengths, and reinspect (as applicable) as specified in paragraph (d) 
of this AD:
    (1) If equal to or less than 2.0 inches in length, within the 
next 200 hours TIS;
    (2) If more than 2.0 inches and less than 2.5 inches in length, 
within the next 50 hours TIS; or
    (3) If 2.5 or more inches in length, prior to further flight.
    (c) If any crack (regardless of length) is found that is not 
parallel (inboard - outboard) to the top of the spar cap, prior to 
further flight, obtain a repair scheme from the manufacturer through 
the Wichita Aircraft Certification Office (ACO), incorporate this 
repair scheme, and reinspect as specified in paragraph (d) of this 
AD.
    (d) Reinspect (fluorescent penetrant) the left and right wing 
front spar upper caps for cracks in accordance with those procedures 
specified in paragraph (a) of this AD at intervals presented within 
the applicable criteria below:
    (1) With cracks less than or equal to 2.0 inches in length that 
are parallel (inboard--outboard) to the top of the spar cap, at 50-
hour TIS intervals until the applicable service kit is installed in 
accordance with paragraph (b) of this AD, and then reinspect 
thereafter at intervals not to exceed 600 hours TIS.
    (2) With cracks found and the applicable SK421-142 or SK425-44 
service kit (-1 for left spar cap and -2 for right spar cap) 
incorporated, at 600-hour TIS intervals.
    (3) With no cracks found and the applicable SK421-142 or SK425-
44 service kit (-1 for left spar cap and -2 for right spar cap) not 
incorporated, at 300-hour TIS intervals; or
    (4) With no cracks found and the applicable SK421-142 or SK425-
44 service kit (-1 for left spar cap and -2 for right spar cap) 
incorporated, no repetitive inspections required.
    (e) 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.
    (f) An alternative method of compliance or adjustment of the 
compliance time that provides an equivalent level of safety may be 
approved by the Manager, Wichita ACO, 1801 Airport Road, Room 100, 
Mid-Continent Airport, Wichita, Kansas 67209. The request shall be 
forwarded through an appropriate FAA Maintenance Inspector, who may 
add comments and then send it to the Manager, Wichita ACO.
    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Wichita ACO.

    (g) The inspections and modifications required by this AD shall 
be done in accordance with ATTACHMENT TO SERVICE BULLETIN to Cessna 
Service Bulletin CQB91-8R1, or the ACCOMPLISHMENT INSTRUCTIONS 
attachment to Cessna Service Bulletin MEB91-7R1, as applicable. The 
modification required by this AD shall be accomplished in accordance 
with Cessna SERVICE KIT SK421-142, dated July 3, 1993, or Cessna 
SERVICE KIT SK425-44, dated November 6, 1992, as applicable. 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 Cessna Aircraft Company, P.O. Box 
7704, Wichita, Kansas 67277. Copies may be inspected at the FAA, 
Central Region, Office of the Assistant Chief Counsel, Room 1558, 
601 E. 12th Street, Kansas City, Missouri, or at the Office of the 
Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.
    (h) This amendment (39-9024) revises AD 91-25-08, Amendment 39-
8109.
    (i) This amendment (39-9024) becomes effective on November 4, 
1994.
    Issued in Kansas City, Missouri, on September 12, 1994.

Barry D. Clements,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 94-23078 Filed 9-16-94; 8:45 am]
BILLING CODE 4910-13-P