AD 96-13-01

This amendment adopts a new airworthiness directive (AD) that applies to MDB Flugtechnik AG Model MD3-160 airplanes. This action requires inserting a supplement Aircraft Flight Manual (AFM), installing a placard prohibiting aerobatics and spinning, inspecting the nosewheel steering system for damaged parts and improper rigging, and if necessary, replacing the parts and re-rigging the nosewheel steering system (NWS). Two incidents on certain MD3-160 airplanes while in flight causing the airplanes to go into a left spin and loose rudder control prior to landing prompted this AD action. The actions specified by this AD are intended to prevent the rudder pedals from locking up and the nosewheel steering from disengaging, which if not detected and corrected, could cause loss of control of the airplane.

96-13-01 MDB FLUGTECHNIK AG : Amendment 39-9669; Docket No. 96-CE-18-AD.
Applicability: Model MD3-160 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 (h) 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 25 hours time-in-service (TIS) after the effective date of this AD, and thereafter, as indicated in this AD.
To prevent the rudder pedals from locking up and the nosewheel steering (NWS) from disengaging, which if not detected and corrected, could cause loss of control of the airplane, accomplish the following:
(a) Insert Temporary Flight Manual Supplement No. TEMP AFM-001, dated April 1995, into the MD3-160 Swiss Trainer Airplane Flight Manual in accordance with the ACCOMPLISHMENT INSTRUCTIONS section, paragraph B (1) in Flugtechnik Service Bulletin (SB) No. MD-SB-27-001, Original Issue May 1995.
(b) Fabricate and install a placard, in an area visible to the pilot (using letters no smaller than 1/8-inch in height) with the following language on the airplane instrument panel:
"AEROBATICS AND SPINNING IN AEROBATIC AND UTILITY CATEGORY IS PROHIBITED"
(c) Inspect the shimmy damper for a bent piston rod and proper operation in accordance with the ACCOMPLISHMENTINSTRUCTIONS section, paragraphs D (1) and (2) of Flugtechnik SB MD-SB-27-001, Original Issue May 1995. If the piston rod is bent, prior to further flight, replace the piston rod in accordance with the applicable portion of the airplane maintenance manual.
(d) Inspect the NWS engage/disengage mechanism and rudder for proper rotation position and excessive rotational play in accordance with paragraphs E (1), (2), and (3) of the service bulletin referenced in paragraph (c) of this AD. If the rotation is not correct or excessive play is evident, prior to further flight, re-adjust the rigging for the rudder/nosewheel steering mechanism in accordance with the applicable portion of the airplane maintenance manual.
(e) Inspect the nosewheel steering for excessive play in the damping mechanism in accordance with paragraphs F (1) through (5) in the service bulletin referenced in paragraph (c) of this AD. If any play exists, prior to further flight, replace the damping pieces and the console covers in accordance with the applicable portion of the airplane maintenance manual.
(f) After the initial inspections, repetitively inspect, at intervals not to exceed 50 hours TIS, in accordance with paragraphs (c), (d), and (e) of this AD.
(g) 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.
(h) An alternative method of compliance or adjustment of the initial or repetitive compliance times that provides an equivalent level of safety may be approved by the Manager, Brussels Aircraft Certification Office, FAA, Europe, Africa, and Middle East Office, c/o American Embassy, B-1000 Brussels, Belgium. The request shall be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then sendit to the Manager, Brussels Aircraft Certification Office.
NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Brussels Aircraft Certification Office.
(i) The inspections and replacements required by this AD shall be done in accordance with MDB Flugtechnik AG Service Bulletin No. MD-SB-27-001, Original Issue May 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 MDB Flugtechnik AG, Flugplatz, CH-3368 Bleienbach, Switzerland. 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.
(j) This amendment becomes effective on July 12, 1996.

The Swiss Federal Office for Civil Aviation (FOCA), which is the airworthiness authority for Switzerland, recently notified the FAA that an unsafe condition may exist on MDB Flugtechnik AG (Flugtechnik) Model MD3-160 airplanes. The Swiss FOCA advises that two incidents on certain MD3-160 airplanes were caused by disengagement of the nosewheel steering while in flight making the airplane roll into a left turn, which was controllable with aileron inputs. The airplane was able to land with restricted rudder control. During the second incident, the pilot was unable to re-engage the nosewheel steering while in flight and prior to landing, and rudder control was never effected. In test flights, the manufacturer has succeeded at reproducing this rudder pedal lockup under unusual combinations of nosewheel steering angle, steering disengage lever position, and rudder pedal position. This situation can only occur when the nose wheel steering disengage link is rotated above its disengage "neutral" position either by excessive nosewheel rotation, or by excessive rotation of the selector lever. The NWS mechanism may be sensitive to play in the nosewheel steering damper block assembly at the top of the nose leg and also sensitive to inconsistencies in rigging procedures. Further investigations have revealed that it is possible to inadvertently damage the disengage mechanism if the nosewheel is maneuvered by a towbar with the steering disengaged.
Flugtechnik has issued service bulletin (SB) No. MD-SB-27-001, Original Issue May 1995, which specifies inserting a supplement to the Aircraft Flight Manual (AFM), fabricating and installing a placard on the instrument panel, and inspecting the NWS system and replacing any damaged parts prior to further flight.
The Swiss FOCA classified this service bulletin as mandatory and issued airworthiness directive (AD) HB 95-303, dated July 17, 1995, in order to assure the continued airworthiness of these airplanes in Switzerland. This airplane model is manufactured in Switzerland and is type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement between the United States and Switzerland. Pursuant to this bilateral airworthiness agreement, the Swiss FOCA has kept the FAA informed of the situation described above.
After examining the circumstances and reviewing all available information related to the incidents described above including that received from the Swiss FOCA, the FAA has determined that AD action should be taken in order to prevent the rudder pedals from locking up and the nosewheel steering from disengaging, which if not detected and corrected, could cause loss of control of the airplane.
Since an unsafe condition has been identified that is likely to exist or develop in other Flugtechnik Model MD3-160 airplanes of the same type design registered for operation in the United States, this AD requires:
- inserting a supplement to the AFM prohibiting aerobatics and spinning,
- fabricating and installing a placard in the pilot s clear view, that prohibits aerobatics and spinning,
- inspecting the NWS engage/disengage mechanism for extensive rotational play, and if rotational play exists, prior to further flight, adjusting the rigging of the rudder/nosewheel steering mechanism, and
- inspecting the shimmy damper for a bent piston rod, and if bent or the damper bottoms out, prior to further flight, replacing the damping pieces.
The actions are to be done in accordance with the instructions in the ACCOMPLISHMENT INSTRUCTIONS section of MDB Flugtechnik AG Service Bulletin No. MD-SB-27-001, Original Issue May 1995.
Comments Invited
Although this action is in the form of a final rule that involves requirements affecting immediate flight safety and, thus, was not preceded by notice and opportunity to 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 should identify the Rules Docket number and be submitted in triplicate to the address specified above. 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 are specifically 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 No. 96-CE-18-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 and 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 (otherwise, an evaluation is not required). A copy of it, if filed, may be obtained from the Rules Docket.
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.
Section 39.13 - [AMENDED]
2. Section 39.13 is amended by adding a new airworthiness directive (AD) to read as follows: