Discussion
What Events Have Caused This AD?
The FAA has received a report of an incident on a Raytheon Model C99 airplane where a cracked main landing gear (MLG) hydraulic actuator end cap resulted in nose landing gear (NLG) collapse during landing. The cracked end cap caused the hydraulic fluid to leak, which then prevented the landing gear from locking down. We have received several other reports of cracks in the MLG hydraulic actuator end caps on certain Raytheon 99 series airplanes of a similar type design.
The suspect MLG hydraulic actuator end caps are part number (P/N) 4A125C32 end caps. These end caps were originally installed on P/N 99-388001 series actuators. We have reports that these parts may also have been installed on the overhauled P/N 99-388008 series, although they are not approved for this configuration.
The P/N 99-388001 and 99-388008 series actuators are installed on Raytheon Models 99, 99A, 99A (FACH), A99, A99A, B99, and C99 airplanes.
What Are the Consequences If the Condition Is Not Corrected?
Cracked MLG hydraulic actuator end caps, if not eliminated and prevented from occurring in the future, could cause hydraulic fluid to leak and result in collapse of one or more gears with consequent aircraft damage and passenger injury.
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 Models 99, 99A, 99A (FACH), A99A, B99, and C99 airplanes. This proposal was published in the Federal Register as a notice of proposed rulemaking (NPRM) on November 2, 2000 (65 FR 65805). The NPRM proposed to require you to inspect all MLG hydraulic actuators to determine the end cap part number that is installed with replacement of any actuator that has a part number 4A125C32 end cap.
Was the Public Invited To Comment?
Interested persons were afforded an opportunity to participate in the making of this amendment. No comments were received on the proposed rule or the FAA's determination of the cost to the public.
Is There Any New Information Pertaining to This Subject?
The FAA's intent is to not affect those airplanes with mechanical landing gear installed either at manufacture or through field approval. The way the NPRM is written would make the AD applicable to all affected airplane models. We are changing the AD to only apply to those airplanes that are equipped with hydraulic landing gear.
We also realized that we inadvertently left off the Raytheon Beech Model A99 airplanes in the Applicability section of the NPRM. These airplanes were originally manufactured with mechanical landing gear, but could have hydraulic landing gear installed. Only 1 of these airplanes is currently on the U.S. Register and FAA has verified that this airplane does not have hydraulic landing gear. Therefore, adding the Beech Model A99 to the AD will not increase the burden upon the public over that already proposed in the NPRM.
FAA's Determination
What Is FAA's Final Determination on This Issue?
After careful review of all available information related to the subject presented above, we have determined that air safety and the public interest require the adoption of the rule as proposed except for the changes described above and minor editorial corrections. We determined that these changes and minor 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
How Many Airplanes Does This AD Impact?
We estimate that this AD could affect 139 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 $60 per hour = $120
No parts necessary to accomplish the inspection.
$120 per airplane
$120 x 139 = $16,680.
We estimate the following costs to accomplish any necessary replacements that will be required based on the results of the inspection. We have no way of determining the number of airplanes that will need such replacement:
Labor cost
Parts cost
Total cost per airplane
4 workhours x $60 per hour = $240.
$1,400 for each actuator; each airplane requires 2 for a total cost of $2,800 per airplane.
$240 + $2,800 = $3,040 per airplane.
Regulatory Impact
Does This AD Impact Various Entities?
The regulations adopted herein 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. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132.
Does This AD Involve a Significant Rule or Regulatory Action?
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, 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.
Sec. 39.13 [Amended]
2. FAA amends Sec. 39.13 by adding a new AD to read as follows: