Discussion
Has FAA taken any action to this point? Reports of cracks in the nose landing gear (NLG) fork on several Raytheon airplanes caused us to issue AD 87-22-01, Amendment 39-5748, and AD 87-22-01 R1, Amendment 39-6312, against certain Raytheon 65, 90, 99, 100, 200, and 1900 series airplanes, and Models 70 and 300 airplanes.
AD 87-22-01 required you to repetitively inspect the nose landing gear (NLG) fork for cracks. If cracks were found during any inspection that exceeded certain limits, you were required to replace the NLG fork with a serviceable part.
AD 87-22-01 R1 retained the repetitive inspection and replacement requirements from AD 87-22-01. AD 87-22-01 R1 also introduced incorporating an improved NLG fork (Kit No. 101-8030-1 S or Kit No. 114-8015-1 S, as applicable) as a terminating action for the repetitive inspection requirements of this AD.
What has happened since AD 87-22-01 R1 to initiate this action? As currently written, AD 87-22-01 R1 allows continued flight if cracks are found in the NLG fork that do not exceed certain limits. In 1996, FAA developed policy to not allow airplane operation when known cracks exist in primary structure, unless the ability to sustain limit and ultimate load with these cracks is proven. The NLG fork is considered primary structure, and the FAA has not received any analysis to prove that limit and ultimate loads can be sustained with cracks in this area.
This AD brings the actions of AD 87-22-01 R1 in compliance with FAA policy. Therefore, FAA has determined the crack limits contained in AD 87-22-01 R1 should be eliminated and that AD action should be taken to require immediate incorporation of Kit No. 101-8030-1 S or Kit No. 114-8015-1 S, as applicable, anytime a crack is found.
This policy did not exist when we issued AD 87-22-01 and AD 87-22-01 R1.
What is the potential impact if FAA took no action? This condition, if not detected and corrected, could cause failure of the NLG fork to carry design limit and ultimate loads. Failure of the NLG fork could result in loss of control of the airplane during take off, landing, and taxi operations.
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 Raytheon Aircraft Company (Raytheon) 65, 90, 99, 100, 200, and 1900 series airplanes, and Models 70 and 300 airplanes. This proposal was published in the Federal Register as a notice of proposed rulemaking (NPRM) on March 18, 2004 (12807). The NPRM proposed to require you to repetitively inspect the nose landing gear (NLG) fork for cracks replacing the NLG fork assembly anytime cracks are found.
Comments
Was the public invited to comment? We provided the public the opportunity to participate in developing this AD. The following presents the comments received on the proposal and FAA's response to each comment:Comment Issue No. 1: Clarify the Applicability
What is the commenter's concern? The commenter states the compliance statement in paragraph (e)(1) of the proposed AD is confusing. The compliance statement requires an initial inspection of the nose landing gear (NLG) fork assembly for any signs of cracks on airplanes not previously affected by AD 87-22-01 R1. This inspection is required within the next 200 hours time-in-service (TIS) after the effective date of this AD. However, it is also stated later in the proposed AD that incorporation of Kit No. 101-8030-1 S or Kit No. 114-8015-1 S (as applicable) is a terminating action to the requirements of the AD and no further action is required. The commenter states that it does not make sense to comply with the initial inspection if you have already done the terminating action.
The commenter states the reason that AD 87-22-01 R1 did not affect most airplanes is because they incorporate Kit No. 101-8030-1 S or Kit No. 114-8015-1S (as applicable).
We infer the commenter wants more clarification to exempt airplanes that incorporate Kit No. 101-8030-1 S or Kit No. 114-8015-1 S (as applicable) from the applicability of the AD.
What is FAA's response to the concern? We agree that additional clarification may help remove confusion about the need to comply with the initial inspection required in the proposed AD. The proposed AD was written to account for the different set of serial numbers affected by AD 87-22-01 R1 and the proposed AD.
We will add a statement to paragraph (c) and (e)(1) to clarify that airplanes that already incorporate Kit No. 101-8030-1 S or Kit No. 114-8015-1 S (as applicable) are exempt from this AD.
We will change the final rule AD based on this comment.
Comment Issue No. 2: Replacement Parts Not Available
What is the commenter's concern? The commenter states that in April 2004, Raytheon Aircraft Company (Raytheon) did not have a supply of replacements kits available. The commenter is concerned that a shortage of replacement kits could ground the affected airplanes.
We infer the commenter wants us to confirm the availability and supply of replacements kits before issuing the final rule AD.
What is FAA's response to the concern? We concur with the commenter that a low supply of replacement kits would be a problem. However, on the effective date of this AD, Raytheon has assured us that replacement kits will be available.
We are not changing the final rule AD based on this comment.
Comment Issue No. 3: Revise the Proposed AD
What is the commenter's concern? The commenter states that AD 87-22-01 R1 sufficiently addresses inspecting and monitoring cracks in the nose landing gear (NLG) fork. The commenter states that no failures occurred after using the procedures and crack limitations set in AD 87-22-01 R1. The commenter adds that he has several hundred thousands of hours of experience with numerous affected airplanes with only three or four cracks found in the past 20 years.
The commenter also disagrees with the FAA's policy (since 1996) to disallow airplane operation when known cracks exist in a primary structure. The commenter states the policy is not justified by quantifiable resulting safety improvements and needs to be revised.
The commenter states the proposed AD imposes an unnecessary economic burden upon the owners/operators of the affected airplanes.
The commenter wants AD 87-22-01 R1 to remain in place since it allows a reasonable period of time after discovering a crack to obtain and install a replacement kit.
What is FAA's response to the concern? We do not concur with the commenter. In 1996, FAA developed policy to not allow airplane operation when known cracks exist in primary structure, unless the ability to sustain limit and ultimate load with these cracks is proven. The NLG fork is considered primary structure, and the FAA has not received any analysis to prove that limit and ultimate loads can be sustained with cracks in this area. For this reason, the FAA has determined the crack limits contained in AD 87-22-01 R1 should be eliminated and that AD action should be taken to require immediate incorporation of Kit No. 101-8030-1 S or Kit No. 114-8015-1 S (as applicable) anytime a crack is found.
We are not changing the final rule AD based on this comment.
Conclusion
What is FAA's final determination on this issue? We have carefully reviewed the available data and determined that air safety and the public interest require adopting the AD as proposed except for the changes discussed above and minor editorial corrections. We have determined that these changes and minor corrections:
--Are consistent with the intent that was proposed in the NPRM for correcting the unsafe condition; and
--Do not add any additional burden upon the public than was already proposed in the NPRM.
Changes to 14 CFR Part 39--Effect on the AD
How doesthe revision to 14 CFR part 39 affect this AD? On July 10, 2002, the FAA published a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs the FAA's AD system. This regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance. 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.
Costs of Compliance
How many airplanes does this AD impact? We estimate that this AD affects 5,296 airplanes in the U.S. registry.
What is the cost impact of this AD on owners/operators of the affected airplanes? We estimate the following costs to accomplish the inspection:
Labor cost
Parts cost
Total cost per airplane
Total cost on U.S. operators
2 workhours x $65 per hour = $130
Not applicable
$130
$130 x 5,296 = $688,480.
We estimate the following costs to accomplish any necessary replacements that will be required based on the results of this inspection. We have no way of determining the number of airplanes that may need this repair/replacement:
Labor cost
Parts cost
Total cost per kit
4 workhours x $65 per hour = $260
Kit No. 101-8030-1 S = $4,152
Kit No. 101-8030-1 S: $260 + $4,152 = $4,412.
Kit No. 114-8015-1 S = $4,210
Kit No. 114-8015-1 S: $260 + $4,210 = $4,470.
Regulatory Findings
Will this AD impact various entities? We have determined that this AD will not have federalism implications under Executive Order 13132. This AD will 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.
Will this AD involve a significant rule or regulatory action? For the reasons discussed above, I certify that this AD:
1. Is not a "significant regulatory action" under Executive Order 12866;2. Is not a "significant rule" under the 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.
We prepared a summary of the costs to comply with this AD and placed it in the AD Docket. You may get a copy of this summary by sending a request to us at the address listed under ADDRESSES. Include "AD Docket No. 2003-CE-51-AD" in your request.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the Amendment
Accordingly, under 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. 106(g), 40113, 44701.
39.13 [Amended]
2. The FAA amends 39.13 by removing Airworthiness Directive (AD) 87-22-01 R1, Amendment 39-6312, and by adding a new AD to read as follows: