AD 96-24-17

[Federal Register Volume 61, Number 245 (Thursday, December 19, 1996)]
[Rules and Regulations]
[Pages 66900-66902]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-30684]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-CE-99-AD; Amendment 39-9841; AD 96-24-17]
RIN 2120-AA64


Airworthiness Directives; The Don Luscombe Aviation History 
Foundation Models 8, 8A, 8B, 8C, 8D, 8E, 8F, T-8F Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
applies to The Don Luscombe Aviation History Foundation (referred to as 
Luscombe from hereon) Models 8, 8A, 8B, 8C, 8D, 8E, 8F, T-8F airplanes. 
This action requires installing new inspection holes, modifying the 
wing tip fairings, and inspecting the wing spars for intergranular 
corrosion. Reports of intergranular corrosion occurring in the wings 
prompted this action. The actions specified by this AD are intended to 
prevent wing spar failure resulting from intergranular corrosion, 
which, if not detected and corrected, could result in structural 
failure of the wings and loss of control of the airplane.

DATES: Effective January 27, 1997.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of January 27, 1997.

ADDRESSES: Service information that applies to this AD may be obtained 
from The Don Luscombe Aviation History Foundation, P. O. Box 63581, 
Phoenix, Arizona 85082; telephone (602) 917-0969 and facsimile (602) 
917-4719. This information may also be examined at the Federal Aviation 
Administration (FAA), Central Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket 95-CE-99-AD, 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: Ms. Lirio L. Liu, Aerospace Engineer, 
FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Blvd., 
Lakewood, California, 90712; telephone (310) 627-5229; facsimile (310) 
627-5210.

SUPPLEMENTARY INFORMATION:

Events Leading to This Action

    A proposal to amend part 39 of the Federal Aviation Regulations (14 
CFR part 39) to include an AD that would apply to Luscombe Models 8, 
8A, 8B, 8C, 8D, 8E, 8F, T-8F airplanes was published in the Federal 
Register on May 29, 1996 (61 FR 26854). The action proposed to require 
installing a total of four additional wing inspection holes in the 
metal covered wings to assist in conducting a more thorough examination 
of the wing spars, modifying the wing tip fairing so that it is 
removable, and providing easier access to the interior of the wings. A 
one time inspection for intergranular corrosion was proposed for both 
metal covered and fabric covered wings on these Luscombe airplanes in 
the areas of the front and rear spar extrusions of the wing 
installations.

Related Service Information

    Accomplishment of the proposed action would be in accordance with 
The Don Luscombe Aviation History Foundation Recommendation #2, dated 
December 15, 1993, Revised November 21, 1995.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Comments were received from three 
commenters on the proposed rule and no comments were received on the 
FAA's determination of the cost to the public. Following are the 
comments and FAA's response.
    The first commenter agreed with the content of the AD, but proposed 
an alternative method for gaining access to the wing spars of the metal 
covered wings, rather than installing the four additional inspections 
holes required by the Don Luscombe Aviation History Foundation Service 
Recommendation #2.
    The FAA concurs and has found the alternative method acceptable. 
This change is justified based on the submittal of analysis and 
acceptability of the method to meet the intent of the AD. Therefore, 
the alternative method procedure suggested by the commenter has been 
included as an Appendix to this AD as an option to paragraphs (a)(1) 
and (a)(2) of this AD.
    The second commenter states that, based on their empirical field 
evidence and maintenance experience, a one-time inspection is 
inadequate and a repetitive inspection on a bi-annual basis should be 
required.
    The FAA does not agree. The corrosive problems prompting this AD 
are intergranular corrosion. This type of corrosion is an attack along 
the grain boundaries of a material (reference Advisory Circular (AC) 
43-4A, Corrosion Control of Aircraft, dated July 25, 1991). Aluminum 
alloys which contain appreciable amounts of copper and zinc are highly 
vulnerable to intergranular corrosion if the alloy is not quenched 
rapidly during heat treatment or other special treatment. This is the 
case for the Luscombe Models 8, 8A, 8B, 8C, 8D, 8E, 8F, T-8F airplane 
wing spars. The intergranular corrosion is a result of manufacturing, 
which affected only a small number of wing spars in the fleet. If 
intergranular corrosion has affected the spars, it should be detectable 
with a one-time inspection, given the age of the fleet in service.
    The third commenter states that the inspection for only 
intergranular corrosion is inadequate and that a repetitive inspection 
on a bi-annual basis should be required to inspect for all other forms 
of corrosion which may be attributed to rodent and bird infestation 
nest residue, which is corrosive to aluminum.
    The FAA partially agrees and partially disagrees with this 
statement. The FAA

[[Page 66901]]

agrees, that while conducting the one-time inspection per the AD, that 
it be noted that other forms of corrosion may be present and should be 
repaired as necessary. However, checking for corrosion on a regular 
basis should be a part of normal care of the airplane. Mandating an 
inspection for corrosion because of a lack of normal maintenance is not 
the function of an AD. Therefore, the AD will not be changed to require 
a repetitive inspection, but the FAA will include a ``Note'' 
recommending inspecting for other forms of corrosion while performing 
the required inspection.

FAA's Determination

    After careful review of all available information related to the 
subject presented above, the FAA has determined that air safety and the 
public interest require the adoption of the rule as proposed except for 
the additional incorporation of an Appendix with an alternative method 
of inspection, a Note recommending inspection for other forms of 
corrosion, and some minor editorial corrections which include changing 
the model designation from Luscombe Model 8 Series (which was how it 
was described in the NPRM), to Luscombe Models 8, 8A, 8B, 8C, 8D, 8E, 
8F, T-8F airplanes. This is the way the airplane is described in the 
type certificate data sheet. Also, the NPRM did not state that if 
corrosion was found, prior to futher flight, replace the corroded part. 
This language has been added in paragraph (b) of the AD. The FAA has 
determined that these corrections will not change the meaning of the AD 
and will not add any additional burden upon the public than was already 
proposed.

Cost Impact

    The FAA estimates that 2,029 airplanes in the U.S. registry would 
be affected by this AD, that it would take approximately 7 hours per 
airplane to accomplish the action, and that the average labor rate is 
approximately $60 an hour. The Luscombe Installation Kit #8007 costs 
approximately $125 per airplane. Based on these figures, the total cost 
impact of this AD on U.S. operators is estimated to be $1,105,805 This 
figure includes the cost of the installation, modification, and 
inspection and only applies to Model 8 airplanes that have metal 
covered wings. For airplanes that have fabric covered wings, the cost 
will only be for the one-time inspection, which is estimated to take 
approximately 1 hour per airplane, and does not include labor and parts 
costs if corrosion is found and a replacement is made.
    Luscombe has informed the FAA that these Installation Kits have 
been distributed to equip approximately 150 airplanes. Assuming that 
these distributed kits are incorporated on the affected airplanes, the 
cost of this AD would be reduced by $81,750 from $1,105,805 to 
$1,024,055.

Compliance Time of This AD

    The FAA has determined that a calendar time compliance is the most 
desirable method because the unsafe condition described by this AD is 
caused by corrosion. Corrosion initiates as a result of airplane 
operation, but can continue to develop regardless of whether the 
airplane is in service or in storage. Therefore, to ensure that the 
above-referenced condition is detected and corrected on all airplanes 
within a reasonable period of time without inadvertently grounding any 
airplanes, a compliance schedule based upon calendar time instead of 
hours time-in-service (TIS) is required.

Regulatory Impact

    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 USC 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding a new airworthiness directive 
(AD) to read as follows:

96-24-17 The Don Luscombe Aviation History Foundation (formerly The 
Luscombe Aircraft Company): Amendment 39-9841; Docket No. 95-CE-99-
AD.

    Applicability: Models 8, 8A, 8B, 8C, 8D, 8E, 8F, and T-8F 
airplanes (all serial numbers), certificated in any category.

    Note 1: This AD applies to each airplane 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 airplanes 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 within the next 12 calendar months after 
the effective date of this AD, unless already accomplished.
    To prevent wing spar failure resulting from intergranular 
corrosion, which, if not detected and corrected, could result in 
structural failure of the wings and loss of control of the airplane, 
accomplish the following:
    (a) For airplanes with metal covered wings:
    (1) Install two additional wing inspection holes (left wing and 
right wing) using the Don Luscombe Aviation History Foundation 
(DLAHF) Kit #8007, Wing Access and Inspection Kit, in accordance 
with the Compliance Procedures section, paragraphs ``1B Metal 
Covered Wings.'', (a), (a1.) through (a9.), and (b.) of The Don 
Luscombe Aviation History Foundation Recommendation #2, dated 
December 15, 1993, Revised November 21, 1995; and,
    (2) Modify the wing tip fairing using the DLAHF Kit #8007, Wing 
Access and Inspection Kit, in accordance with the Compliance 
Procedures section, paragraphs ``1B Metal Covered Wings.'', (c), and 
(c1.) through (c5.) of The Don Luscombe Aviation History Foundation 
Recommendation #2, dated December 15, 1993, Revised November 21, 
1995.
    (b) For all affected airplanes, inspect one time for 
intergranular corrosion in the areas of the front and rear spar 
extrusions of the wing installations and if corrosion is found, 
prior to further flight, replace the corroded

[[Page 66902]]

part in accordance with the Compliance Procedures section, paragraph 
``1A. Fabric Covered Wings.'' or paragraph ``2. Inspect'' of The Don 
Luscombe Aviation History Foundation Recommendation #2, dated 
December 15, 1993, Revised November 21, 1995, whichever paragraph is 
applicable to the wing construction of the airplane.
    (c) For airplanes with metal covered wings, an alternative 
method of compliance for the required modification in paragraphs 
(a)(1) and (a)(2) of this AD can be accomplished in accordance with 
the procedures contained in the Appendix to this AD.

    Note 2: Although not required by this AD, the FAA recommends 
inspection of the spars for other forms of corrosion which may be a 
result of nest residue from rodent and bird infestation within the 
cavity of the wing. If corrosion is detected, it should be treated 
by the recommended maintenance procedures (reference Advisory 
Circular 43-4A, Corrosion Control for Aircraft, dated July 25, 
1991).

    (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 airplane to a location where 
the requirements of this AD can be accomplished.
    (e) An alternative method of compliance or adjustment of the 
compliance time that provides an equivalent level of safety may be 
approved by the Manager, Los Angeles Aircraft Certification Office, 
3960 Paramount Blvd., Lakewood, California, 90712. The request shall 
be forwarded through an appropriate FAA Maintenance Inspector, who 
may add comments and then send it to the Manager, Los Angeles 
Aircraft Certification Office.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles Aircraft Certification Office.

    (f) The inspections and modifications required by this AD shall 
be done in accordance with The Don Luscombe Aviation History 
Foundation Recommendation #2, dated December 15, 1993, Revised 
November 21, 1995. 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 The Don 
Luscombe Aviation History Foundation, P. O. Box 63581, Phoenix, 
Arizona 85082; telephone (602) 917-0969 and fax (602) 917-4719.
    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.
    (g) This amendment (39-9841) becomes effective on January 27, 
1997.

Appendix to AD 96-24-17

I. Inspection Procedures for Luscombe Model 8, 8A, 8B, 8C, 8D, 8E, 8F, 
T-8F Airplanes That Have Not Accomplished the Inspection in Accordance 
With the Procedures in the Don Luscombe Aviation History Foundation 
Recommendation #2, Dated December 15, 1993; Revised November 21, 1995

    1. Remove ALL existing wing root fairings, wing inspection hole 
covers, and wing strut cover plates on both the right and left wing.
    2. Loosen the four wing spar root attach bolts on both the right 
and left wings to permit a small wing angulation.
    3. Perform a visual inspection of the extruded rear spar aft 
face of the left and right wing.
    4. Inspect the spar from the root to the spliced sheet metal tip 
spar at the wing root fairing location.
    5. To permit removal of the wing strut, unbolt the wing strut 
and remove the strut.

    Note: In the location under a spar, support the wing half at 
normal height by any stable means, such as a ladder and padded 
lashed block. Avoid excess vertical angulation of the wing as this 
may stress the wing root attach point.

    6. Using suitable light and the access gained by the wing strut 
hole, visually inspect the front of the rear spar and the rear of 
the front spar for abnormal bulges or erupted spar surfaces. (See 
also Note 2 in the body of AD 96-24-17)
    7. Remove the wing tip fairing by drilling out the rivets (using 
a #30 drill or smaller), and inspect the spars for abnormal bulges 
or erupted spar surfaces in the ``U channel attach area'' of each 
spar, and the outer lengths to the splices of the sheet metal spar 
extrusions. (See Note 2 in the body of AD 96-24-17)

    Note: Inspection of the front of the front spar may be performed 
by using the existing inspection holes and a ``light trolley'' on 
the upper aileron cable. The light trolley is made from a standard 
clear 110 volt bathroom night light connected to a candelabra socket 
lamp extension cord. Attach the light trolley to the upper aileron 
cable with a tie wrap, connect a wire of suitable length to the tie 
wrap and use this as a means to move the light along the face of the 
spar.

    8. Reattach wing tip fairings with approved sheet metal screws 
or approved pop rivets.
    9. Reassemble wing strut on inspected wing, protecting the root 
joint by avoiding excess vertical deflection. Check the lock nuts 
for wear and replace as necessary. Torque the strut ends and wing 
root bolts using adequate torque (do not over torque the attach 
fittings).
    10. If evidence of intergranular corrosion is detected, remove 
and replace the corroded part with an airworthy part.
    11. Upon completion of the inspection, replace the wing root 
fairings, wing inspection hole covers and wing strut covers.

    Issued in Kansas City, Missouri, on November 25, 1996.
Henry A. Armstrong,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-30684 Filed 12-18-96; 8:45 am]
BILLING CODE 4910-13-U