Events Leading to the Issuance of This AD
A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that applies to certain Cessna 180 and 185 series airplanes that have either Airglas Engineering Company, Inc., (AECI) Model LW3600-180 (single position) or Model LW3600-180A (two position) fixed penetration wheel skis installed in accordance with STC SA213AL was published in the Federal Register as a notice of proposed rulemaking (NPRM) on June 26, 1998 (63 FR 34833). The NPRM proposed to supersede AD 80-10-01, Amendment 39-3762, which currently requires modifying the ski bungee assemblies, safety cables, and check cables, and their attachments to the airplane and the skis; limiting the maximum airspeed to 160 knots with skis installed; and installing an airspeed limitation placard. The NPRM proposed to require the following:
Modifying the ski bungee assemblies, safety cables, and check cables, and their attachments to the airplane and the skis;
Installing a placard adjacent to the airspeed indicator limiting the never exceed speed to 160 knots with the skis installed;
Re-marking the airspeed indicator to display the reduced never exceed speed (160 KIAS) and the reduced maximum structural cruising speed (139 KIAS) with the skis installed; and
Placing AECI Document No. AE97-13FM, "Supplemental Airplane Flight Manual and Airplane Flight Manual Supplement", dated October 10, 1997, in the airplane cockpit.
Accomplishment of the proposed actions as specified in the NPRM would be required in accordance with AECI Service Bulletin (SB) No. LW3600-3, originally issued: September 21, 1979; Amended: October 10, 1997; AECI Drawing No. LW3600-180A-1 and -2, Revision "B", dated September 21, 1979; AECI Drawing No. LW3600-180A-3, Revision "A", dated April 30, 1979; AECI Drawing No. LW3600-180, Revision "F", dated September 21, 1979 (for single position wheel ski installations) or AECI Drawing No. LW3600-180A, Revision "E", dated September 21, 1979 (for two position wheel ski installations); AECI Drawing No. LW3600-180A-11, originally issued: September 21, 1979; and AECI Document AE97-13FM, "Supplemental Airplane Flight Manual and Airplane Flight Manual Supplement", dated October 10, 1997.
The NPRM was the result of field reports of incidents occurring on the affected airplanes that were in compliance with AD 80-10-01, and the fact that Cessna Model 180K airplanes were inadvertently left out of the existing AD.
Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the following comments received.
Comment Disposition
The one commenter states that requiring re-marking of the airspeed indicator to display the reduced airspeed limits will not fix the problem because airplane operators that ignore placard requirements will also ignore the airspeed indicator requirements. This commenter operates one of the affected airplanes with skis for 6 months out of each year.
The commenter states that, if the proposed AD is adopted, he will have to accomplish pitot and static pressure checks required by current regulation every 6 months when he changes the airspeed indicator during ski installation and removal.
The commenter also states that skis are similar to other devices, such as landing gear, flaps, ramps, and doors that are affixed to or incorporated into aircraft. The commenter states that the maximum speed at which the other devices can be extended or opened in flight are specified only by placards and not by markings on the airspeed indicator.
The commenter goes on to state that, based on the above information, the costs of installing and removing the skis will become extremely high, and the commenter asks the FAA to remove the requirement of re-marking the airspeed indicator to display the reduced airspeed limits.
The FAA does not concur thatthe requirement in the proposed AD of re-marking the airspeed indicator is not justified.
The FAA s intent of requiring that the airspeed indicator be re-marked is not to provide another airspeed limit indication for certain pilots to ignore, but to provide consistent indications of airspeed limits, i.e., to eliminate the confusion generated by having the information in an airspeed limitation placard contradicting the airspeed indicator.
The proposed AD requires re-marking the airspeed indicator, but does not specifically require removing the existing airspeed indicator and replacing it with one marked differently. If the existing airspeed indicator is left in place and re-marked, no pitot and static pressure checks would be required. Each airplane owner/operator has the choice of changing the markings of the airspeed indicator either by replacing the airspeed indicator or by re-marking the existing airspeed indicator without removing it.
The FAA understands that an owner/operator who decides to replace the airspeed indicator will have to accomplish pitot and static pressure checks each time the airspeed indicator is replaced and that there are costs involved with this. However, the FAA has determined that the safety benefits of eliminating the confusion caused when the airspeed indicator contradicts current placards far outweigh this burden.
In addition, the FAA does not consider skis similar to other devices, such as landing gear, flaps, ramps, and doors that are affixed to or incorporated into aircraft. The compared items are all ones that can be extended or opened and retracted or closed during flight. On the other hand, the installation of skis on aircraft changes the aircraft s configuration until the skis are removed. Fixed penetration wheel skis cannot be extended or opened and then retracted or closed.
The commenter s assertion that the maximum speed at which wing flaps can be extended in flight is not specified by airspeed indicator markings is incorrect. The range of airspeeds over which the flaps of a small airplane can be extended in flight is specified by a white arc on the airspeed indicator. The upper end of the white arc is the maximum speed at which the flaps can be extended.
No changes have been made to the final rule as a result of these comments.
The 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 minor editorial corrections. The FAA has determined that these minor corrections will not change the meaning of the AD and will not impose any additional burden upon the public than was already proposed.
Cost Impact
The FAA estimates that 170 airplanes in the U.S. registry will be affected by this AD, that it will take approximately 4 workhours per airplane to accomplish this action, and that the average labor rate is approximately $60 an hour. Parts cost approximately $350 per airplane. Based on these figures, the total cost impact of this AD on U.S. operators is estimated to be $100,300, or $590 per airplane.
AECI has informed the FAA that approximately 12 of the affected airplanes have the modification required by this AD already incorporated. Based on this, the cost impact of the proposed AD is reduced by $7,080, from $100,300 to $93,220.
None of the above figures take into account the costs involved if operators would have to re-accomplish the work, i.e., ski removal and re-installation.
AD 80-10-01 currently requires most of the same actions on the affected airplanes that are required by this AD. The only differences between this AD and AD 80-10-01 are the addition of Cessna Model 180K airplanes to the applicability and the requirements for re-marking the airspeed indicator and placing an AFM supplement in the cockpit. Fabricating and installing the placard, placing theAFM supplement in the cockpit, and re-marking the airspeed indicator (provided the indicator is re-marked by painting the outside of the glass) can be accomplished by:
For airplanes operated in accordance with part 91 of the Federal Aviation Regulations (14 CFR part 91): An owner/operator who holds at least a private pilot s certificate; and
For airplanes operated in accordance with part 135 of the Federal Aviation Regulations (14 CFR part 135): An operator who holds an operating certificate issued under part 135 of the Federal Aviation Regulations (14 CFR part 135), as authorized by sections 43.3, 43.7, and 43.9 of the Federal Aviation Regulations (14 CFR 43.3, 43.7, and 43.9).
The only cost impact upon the public for airplanes other than the affected Cessna Model 180K airplanes is the time it will take the affected airplane owners/operators to incorporate these actions. Therefore, this AD has no additional cost impact over that already required by AD 80-10-01, except for the costs associated with the affected Cessna Model 180K airplanes.
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 U.S.C. 106(g), 40113, 44701.
39.13 [Amended]
2. Section 39.13 is amended by removing Airworthiness Directive (AD)80-10-01, Amendment 39-3762, and by adding a new AD to read as follows: