Airworthiness Directive · Amendment 39-11954 · Empresa Brasileira de Aeronautica S.A. (EMBRAER) Model EMB-120 Series Airplanes
Empresa Brasileira de Aeronautica S.A. (EMBRAER) Model EMB-120 Series Airplanes
Model EMB-120 series airplanes, serial numbers 120-0001 through 120-0333 inclusive; 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 (c) 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.
This amendment adopts a new airworthiness directive (AD), applicable to certain EMBRAER Model EMB-120 series airplanes, that requires inspections of certain components, and corrective action, if necessary. The actions specified by this AD are intended to prevent deterioration and deformation of the mass-balance weights of the aileron, which could affect the surface balance of the aileron and result in loss of aileron control and consequent reduced controllability of the airplane. This action is intended to address the identified unsafe condition.
To prevent deterioration and deformation of the mass-balance weights of the aileron, which could affect the surface balance of the aileron and result in loss of aileron control and consequent reduced controllability of the airplane, accomplish the following:
(a) For airplanes having serial numbers 120-0291, 120-0294, and 120-0296 through 120-0333 inclusive: Within 150 flight hours after the effective date of this AD, measure the clearance between the aileron mass-balance weights and attach fittings on the left and right sides of the airplane, in accordance with PART I of the Accomplishment Instructions of EMBRAER Service Bulletin 120-27-0077, Change No. 01, dated October 24, 1997.
(1) If the clearance is within the acceptable limits described in the service bulletin, thereafter, repeat the measurement at intervals not to exceed 1,000 flight hours until the actions required by paragraph (b) of this AD have been accomplished.
(2) If the clearance is outside the acceptable limits described in the service bulletin, prior to further flight, replace the affected mass-balance weight with a new, improved mass-balance weight, in accordance with PART III of the Accomplishment Instructions of the service bulletin. Such replacement terminates the requirement to accomplish paragraph (b) of this AD.
(b) For all airplanes: Within 2,000 flight hours after the effective date of this AD, perform a one-time detailed visual inspection of the aileron mass-balance weights to detect any cavity, hole, or delamination, in accordance with PART II of the Accomplishment Instructions of EMBRAER Service Bulletin 120-27-0077, Change No. 01, dated October 24, 1997. Such inspection constitutes terminating action for the repetitive inspections required by paragraph (a)(1) of this AD for airplanes subject to paragraph (a) of this AD.
(1) If no cavity, hole, or delamination is detected: Prior to further flight, perform a one-time detailed visual inspection to detect white powder on the surface of the mass-balance weights, in accordance with PART II of the Accomplishment Instructions of the service bulletin. If any white powder is found, remove the white powder in accordance with the service bulletin.
(2) If any cavity, hole, or delamination is found, prior to further flight, replace the affected mass-balance weight with a new, improved mass-balance weight, in accordance with PART III of the Accomplishment Instructions of the service bulletin.
