Airworthiness Directives; DAHER (Type Certificate Previously Held by SOCATA) Airplanes

SUPPLEMENTARY INFORMATION:

Background

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2016-08-08, Amendment 39-18484 (81 FR 21711, April 13, 2016) (AD 2016-08-08). AD 2016-08-08 applied to SOCATA (type certificate now held by DAHER) Model MS 880B, MS 885, MS 892A-150, MS 892E-150, MS 893A, MS 893E, MS 894A, MS 894E, Rallye 100S, Rallye 150ST, Rallye 150T, Rallye 235C, and Rallye 235E airplanes.

AD 2016-08-08 was prompted by MCAI originated by European Union Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union. EASA issued AD 2015-0203, dated October 7, 2015 (EASA AD 2015-0203) to correct an unsafe condition identified as fatigue failure of the NLG wheel axle. EASA AD 2015-0203 was prompted by an NLG wheel axle failure that occurred in service. The investigation revealed that this failure was due to fatigue caused by premature wear. EASA AD 2015-0203 required retaining the requirements of Direction Générale de l'Aviation Civile (DGAC) France AD 91-163(A)R2, dated March 30, 1994, which was superseded, but required those actions to be accomplished within reduced intervals.

AD 2016-08-08 required doing repetitive detailed visual inspections of the intersection between the axle radius and the NLG fork area for chafing; doing repetitive dye penetrant inspections on the NLG wheel axle for cracks, distortion, and nicks or wear; corrective actions if necessary; and replacing the NLG wheel axle attachment screws with new screws. The FAA issued AD 2016-08-08 to address chafing and cracking of the NLG wheel axle, which could lead to failure of the NLG with consequent damage to the airplane and/or injury to occupants.

Since the FAA issued AD 2016-08-08, EASA superseded EASA AD 2015-0203 and issued EASA AD 2023-0080, dated April 17, 2023 (EASA AD 2023-0080) (also referred to as the MCAI) to correct an unsafe condition for all DAHER AEROSPACE Model MS 880 B, MS 880 B-D, MS 881, MS 883, MS 884, MS 885, MS 886, MS 887, MS 890 A, MS 890 B, MS 892 A.150, MS 892 B.150, MS 892 E.150, MS 892 E-D.150, MS 893 A, MS 893 B, MS 893 E, MS 893 E-D, MS 894 A, MS 894 E, RALLYE 100 S, RALLYE 100 S-D, RALLYE 100 ST, RALLYE 100 ST-D, RALLYE 110 ST, RALLYE 150 ST, RALLYE 150 ST-D, RALLYE 150 T, RALLYE 150 T-D, RALLYE 150 SV, RALLYE 150 SVS, RALLYE 180 T, RALLYE 180 TS, RALLYE 180 T-D, RALLYE 235 A, RALLYE 235 F, RALLYE 235 E, and RALLYE 235 E-D airplanes.

The MCAI states that it retains the requirements of EASA AD 2015-0203 but introduces a new inspection method and a new design of the NLG wheel axle as a terminating action for the repetitive detailed inspections. You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2024-1480.

The NPRM published in the Federal Register on June 4, 2024 (89 FR 47879). In the NPRM, the FAA proposed to retain none of the requirements of AD 2016-08-08. The NPRM proposed to require repetitively inspecting the NLG wheel axle and, if chafing, cracking, or damage was found, installing the newly designed NLG wheel axle and attachment screws, which would terminate the actions specified in the proposed AD. The NPRM also proposed a magnetic particle inspection after a visual inspection if no damage was found, or when installing an airworthy part that was previously in service. The NPRM also proposed to require repetitively replacing the NLG wheel axle attachment screws.

Discussion of Final Airworthiness Directive

Comments

The FAA received no comments on the NPRM or on the determination of the costs.

Change Since NPRM Was Published

The NPRM proposed to require repetitively replacing the NLG wheel axle attachment screws every 2,000 hours time-in-service (TIS). The FAA re-evaluated this requirement and determined that clarification of the intent of this requirement is needed. The FAA revised paragraph (i) of this AD to clarify that any screw found to be distorted, scratched, nicked, or worn during any repetitive inspection required by paragraph (h)(1) of this AD must be replaced before further flight. If no screw is found to be distorted, scratched, nicked, or worn during any repetitive inspection required by paragraph (h)(1) of this AD, all of the NLG wheel axle attachment screws must be replaced initially before exceeding 2,000 hours TIS total on the airplane; before exceeding 2,000 hours TIS since the last time the attachment screws were replaced; or within 50 hours TIS after the effective date of this AD, whichever occurs later, and repetitively thereafter at intervals not to exceed 2,000 hours TIS after the last replacement.

Conclusion

These products have been approved by the aviation authority of another country and are approved for operation in the United States. Pursuant to the FAA's bilateral agreement with this State of Design Authority, it has notified the FAA of the unsafe condition described in the MCAI referenced above. The FAA reviewed the relevant data and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on these products. Except for the change described previously, this AD is adopted as proposed in the NPRM. This change will not increase the economic burden on any operator.

Material Incorporated by Reference Under 1 CFR Part 51

The FAA reviewed Daher Service Bulletin SB 150, Revision 4, dated January 2023. This material specifies procedures for preparing, inspecting, replacing, and reconditioning the NLG wheel axle. This material also specifies procedures for replacing the NLG wheel axle attachment screws.

This material is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.

Differences Between This AD and the MCAI

The applicability of the MCAI includes DAHER AEROSPACE Model MS 886, MS 887, MS 890 A, MS 890 B, MS 892 B.150, MS 892 E-D.150, MS 893 B, MS 893 E-D, RALLYE 100 S-D, RALLYE 100 ST, RALLYE 100 ST-D, RALLYE 110 ST, RALLYE 150 ST-D, RALLYE 150 T-D, RALLYE 150 SV, RALLYE 150 SVS, RALLYE 180 T, RALLYE 180 TS, RALLYE 180 T-D, RALLYE 235 A, RALLYE 235 F, and RALLYE 235 E-D airplanes and the applicability of this AD does not because these models do not have an FAA type certificate.

Costs of Compliance

The FAA estimates that this AD affects 32 airplanes of U.S. registry.

The FAA estimates the following costs to comply with this AD: