AD 94-04-07 ACTIVE

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Beech Model 400A airplanes. This action requires rework or replacement of certain hubcaps on the main landing gear. This AD also requires incorporation of procedures into the FAA-approved maintenance program for inspections of the transducer drive clip to ensure that the drive clip gap does not exceed a specified limit. This amendment is prompted by a report that a Beech Model 400A airplane lost its anti-skid braking system during landing roll out. The actions specified in this AD are intended to prevent degradation or loss of braking performance.

Comments for inclusion in the Rules Docket must be received on or before April 19, 1994.

Final rule; request for comments.

94-04-07 BEECH AIRCRAFT CORPORATION: Amendment 39-8827. Docket 94-NM-11-AD.

Applicability: Model 400A airplanes; serial numbers RK-1 through RK-23 inclusive, on which BEECHCRAFT Kit No. 128-8001-1 S (increased landing weight modification) is installed; and serial numbers RK-24 through RK-76 inclusive; certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent degradation or loss of braking performance, accomplish the following:

(a) Within 25 hours time-in-service or 30 days after the effective date of this AD, whichever occurs first, accomplish the requirements of paragraphs (a)(1) and (a)(2) of this AD:

(1) Replace the existing left- and right-hand hubcaps on the main landing gear with new hubcaps, part number 140-03121-1; or rework the existing hubcaps by adding a spacer between the hubcap drive clip and the hubcap and reidentifying the hubcap assembly as part number 140-03121-1; in accordance with Beechcraft Service Bulletin No. 2549, dated January 1994.

(2) Incorporate into the FAA-approved maintenance inspection program the procedure described in Beechcraft Service Bulletin No. 2549, dated January 1994, for inspecting the transducer drive clip to ensure that the drive clip gap does not exceed 0.20 inch, which must be accomplished each time a hubcap is removed.

NOTE 1: The Beechcraft service bulletin references Crane Hydro-Aire Service Bulletin No. 140-031-32-1, dated December 17, 1993, as an additional source of service information.

(b) After the effective date of this AD, no person shall install a hubcap assembly, part number 140-03121, on any airplane.

(c) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Wichita Aircraft Certification Office (ACO), FAA, Small Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal 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.

(d) Special flight permits may be issued in accordance with Federal Aviation Regulations (FAR) 21.197 and 21.199 to operate the airplane to a location where the requirements of this AD can be accomplished.

(e) The rework and replacement shall be done in accordance with Beechcraft Service Bulletin No. 2549, dated January 1994. 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 Beech Aircraft Corporation, P.O. Box 85, Wichita, Kansas 67201-0085. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(f) This amendment becomes effective on March 7, 1994.

The FAA has received a report that a Beech Model 400A airplane lost its anti-skid braking system during landing roll out. In addition, the FAA has received reports that other Model 400A airplanes have also experienced similar problems with the anti-skid system. Although the exact cause of the brake failure is undetermined, results of tests and inspections of the brakes and the anti-skid system on these airplanes have revealed that only marginal engagement may occur between the main wheel hubcap drive clip and the anti-skid wheel speed transducer. Lack of adequate engagement between the drive clip and the transducer could cause the transducer to send erroneous signals to the anti-skid control box. This condition, if not corrected, could result in degradation or loss of braking performance.

Model 400A airplanes are equipped with a back-up emergency braking system. Power brake failure procedures contained in the Emergency Procedures section of the FAA-approved Airplane Flight Manual (AFM) specify that the required landing distance will increase by approximately 50 percent when the brakes have failed and the emergency brake system is activated. This increase assumes that brake failure is recognized. In certain brake failure conditions caused by the drive clip not being fully engaged, the pilot may not immediately recognize the degradation of braking performance. In this case, the required landing distance could increase by 70 percent or more.

Federal Aviation Regulation (FAR) 25.735 specifies, in part, that single failures in brake systems are acceptable, as long as the airplane can be brought to rest under the landing performance conditions specified in FAR 25.125 with a mean deceleration during the landing roll of at least 50 percent of that obtained during normal landing performance. Since Beech Model 400A airplanes operate under part 91 of the FAR, the AFM allows landings on a runway as short as the actual landing distance determined under FAR 25.125, if the normal brake system is operating. If the normal brake system fails and the pilot must revert to the emergency brake system, the actual landing distance required could easily exceed the actual runway length available.

The FAA has reviewed and approved Beechcraft Service Bulletin No. 2549, dated January 1994, that describes procedures for replacement of certain hubcaps on the main landing gear with new hubcaps, or rework and reidentification of certain hubcaps. The rework involves adding a spacer between the hubcap drive clip and the hubcap, and reidentifying the hubcap assembly with a specified part number. Accomplishment of these actions will prevent loss of anti- skid braking action due to intermittent wheel speed transducer signals. The service bulletin also describes procedures for an inspection of the transducer drive clip to ensure that the drive clip gap does not exceed a specified limit. The Beechcraft service bulletin referencesCrane Hydro-Aire Service Bulletin No. 140-031-32-1, dated December 17, 1993, as an additional source of service information.

Since an unsafe condition has been identified that is likely to exist or develop on other Model 400A airplanes of the same type design, this AD is being issued to prevent degradation or loss of braking performance. This AD requires rework or replacement of certain hubcaps on the main landing gear. This AD also requires incorporation of procedures into the FAA-approved maintenance program for inspections of the transducer drive clip to ensure that the drive clip gap does not exceed a specified limit. The rework or replacement is required to be accomplished in accordance with the Beechcraft service bulletin described previously. The inspection procedure is also referenced in that service bulletin.

Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.

Comments Invited
Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.

Comments arespecifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 94-NM-11-AD." The postcard will be date stamped and returned to the commenter.

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.

The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, may be obtained from 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 14 CFR part 39 of the Federal Aviation Regulations 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.

39.13 - [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-103, Attention: Rules Docket No. 94-NM-11-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

The service information referenced in this AD may be obtained from Beech Aircraft Corporation, P.O. Box 85, Wichita, Kansas 67201-0085. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Small Airplane Directorate, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Dale A. Vassalli, Aerospace Engineer, Systems and Equipment Branch, ACE-130W, FAA, Small Airplane Directorate, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas 67209; telephone (316) 946-4132; fax (316) 946-4407.