AD 98-20-01

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Bombardier Model CL-600-2B19 (Regional Jet Series 100) series airplanes. This action requires revising the Airplane Flight Manual (AFM) to provide the flight crew with revised procedures for checking the flap system. This AD also requires revising the maintenance program to provide procedures for checking the flap system, and performing follow-on actions, if necessary. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified in this AD are intended to prevent an unannunciated failure of the flap system, which could result in a flap asymmetry, and consequent reduced controllability of the airplane.

Final rule; request for comments

98-20-01 BOMBARDIER, INC.: Amendment 39-10767. Docket 98-NM-236-AD.\n\tApplicability: Model CL-600-2B19 (Regional Jet Series 100) series airplanes, serial numbers 7003 and subsequent; certificated in any category. \n\n\tNOTE 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.\n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent an unannunciated failure of the flap system, which could result in a flap asymmetry, and consequent reduced controllability of the airplane, accomplish the following: \n\n\tNOTE 2: Bombardier Service Letter RJ-SL-27-002A, dated April 8, 1998, and Service Letter RJ-SL-27-037, dated July 2, 1998, may provide operators with additional information concerning the actions required by this AD. However, accomplishment of the procedures specified in these service letters should not be considered to be an acceptable method of compliance with the requirements of this AD.\n\n\t(a)\tWithin 10 days after the effective date of this AD, accomplish the requirements of paragraphs (a)(1), (a)(2), and (a)(3) of this AD.\n\n\t\t(1)\tRevise the Limitations Section of the FAA-approved AFM to include the following procedures and Figures 1 and 2 of this AD.\n\n\t"Air Operator Actions\n\n\tIMPORTANT: If the outboard flap position is outside the "GO" range, as shown infigure 2., further \tflight is prohibited until required maintenance actions have been accomplished.\n\n\t\t1.\tTouch-and-go landings for the purposes of training must be accomplished using a flap setting of 20 degrees for the entire procedure.\n\n\t\t2.\t(a)\tTake-off flaps must be set prior to departure, and\n\t\n\t\t(b)\tAn external visual check must be accomplished to detect any twisting, skewing, or abnormal deformation of the flaps, using the information given in Figures 1 and 2.\n\n\t\tNote 1: If the outboard flap position is outside the "GO" range as shown in figure 2., further flight is prohibited until required maintenance actions have been accomplished.\n\n\t\tNote 2: This visual check must be accomplished either by a member of the flight crew or by maintenance personnel, and the results reported directly to the pilot-in-command prior to take-off.\n\n\t\t3.\tIf any additional change to the flap position is necessary, prior to take-off, accomplish the visual check specified by the preceding paragraph 2. (b)."\n\n\t(2)\tRevise the Normal Procedures Section of the FAA-approved AFM to include the following procedures:\n\n\t\t"To minimize a possible flap twist in flight when operating flaps, operate the flap selector sequentially, stopping at each setting (i.e., 0 degrees, 8 degrees if applicable, 20 degrees, 30 degrees, 45 degrees; or operate the flap selector in reverse order), and waiting for the flaps to reach each position before selecting the next setting. Monitor the control wheel for abnormal control wheel angles during each transition in flap position.\n\n\t\tNote: This procedure is not applicable during a go-around or during any emergency aircraft handling procedure where prompt flap retraction is required. In these cases, follow the applicable AFM procedures."\n\n\t\t(3)\tRevise the Abnormal Procedures Section of the FAA-approved AFM to include the following procedures:\n\n\t\t"If abnormal aileron control wheel angles develop during flap operation with the autopilot on, orif the aircraft rolls without pilot input with the autopilot off (with or without a ?FLAPS FAIL' caution message), perform the following actions:\n\n\t\t1.\tIf flaps are being extended, immediately return the flaps to the previously selected position (e.g., for flaps selected from 8 degrees to 20 degrees, re-select 8 degrees).\n\n\t\t2.\tIf flaps are being retracted, the flap selector should remain in the currently selected position (e.g., for flaps selected from 20 degrees to 8 degrees, leave selector at 8 degrees).\n\n\t\t3.\tDo not attempt to operate the flaps any further.\n\n\t\t4.\tIf the flaps are engaged, disconnect the autopilot.\n\t\tNote: When disconnecting the autopilot, anticipate an out-of-trim situation and hold the aileron control wheel in its current position.\n\n\t\t5.\tFor landing, perform the "Flaps Failure" procedure for the following conditions:\n\n\t\t\t(a)\tIf an abnormal aileron control wheel angle to the left develops, do not land if a crosswind from the left is greater than 20 knots.\n\n\t\t\t(b)\tIf an abnormal aileron control wheel angle to the right develops, do not land if a crosswind from the right is greater than 20 knots.\n\n\t\t6.\tAfter landing, do not attempt to retract the flaps. Record the event in the Aircraft Maintenance Log Book and notify the person responsible for maintenance."\n\nNORMAL/ABNORMAL OUTBOARD FLAP CONFIGURATION IN TAKE-OFF POSITION\n\n\tNote: View looking forward on left wing trailing edge (right side opposite).\n\n1.\tNORMAL\n\nA normal outboard flap has a straight trailing edge, and the inboard corner is slightly above (i.e. higher) than the inboard flap.\n\n\n\n2.\tABNORMAL\n\nThe following are indications of an outboard flap with a twist, skew or abnormal deformation:\n\n\t-\tNoticeable curve in the trailing edge\n\t-\tBuckled top or bottom surface\n\t-\tHigher than normal position of the inboard trailing edge corner\n\n\n\nFigure 1. Normal/Abnormal Outboard flap Configuration in Take-off Position\n\n\nOUTBOARD FLAP GO/NO-GO CRITERIA IN TAKE-OFF POSITION\n\n\tNOTE\t1.\tThese criteria are applicable for any size of hand.\n\t\t2.\tView looking forward on left wing trailing edge (right side opposite).\n\nIf the outboard flap position is outside the "GO" range as shown below, further flight is prohibited.\n\n1.\tFLAP AT 8 DEGREES\n\n\n\n\n2.\tFLAP AT 20 DEGREES\n\n\n\n\nFigure 2. Outboard Flap Go/No-Go Criteria in Take-off Position\n\n\t(b)\tWithin 10 days after the effective date of this AD, revise the FAA-approved maintenance program to include the following procedures and Figures 1 and 2 of this AD: \n\n\t"Maintenance Procedure\n\n\t Whenever a ?FLAPS FAIL' caution message occurs, carry out the following procedures after landing:\n\n\t\tNote: These procedures are to be accomplished by maintenance personnel only.\n\n\t\t1.\tCheck that there have been no other ?FLAPS FAIL' caution messages reported within the previous 72 hours. If a previous message has been reported, prior to further flight, perform the actions required in the following Maintenance Action section. If no previous ?FLAPS FAIL' caution message has been reported, continue with the following:\n\n\t\t2.\tCarry out an external visual check of each outboard flap for evidence of twisting, skewing, or abnormal deformation. (Reference Figures 1 and 2.)\n\n\t\t3.\tIf there is no evidence of twisting, skewing, or abnormal deformation, proceed as follows: \n\n\t\t\t(a)\tReset the flap system ONLY ONCE by cycling circuit breakers CB1-F4 and CB2-F4.\n\t\t\t(b)\tIf the system does not reset (i.e., the ?FLAPS FAIL' caution message is still posted), prior to further flight, perform the actions required in the following Maintenance Action section.\n\n\t\t\t(c)\tIf the system resets, cycle the flaps to 45 degrees and back to 0 degrees. Continued flap operation for up to a maximum of 72 hours is then permitted as long as no additional ?FLAPS FAIL' caution message is indicated.\n\n\t\t\t(d)\tIf an additional ?FLAPS FAIL' caution message occurs within the period of 72 hours, as specified above, prior to further flight, perform the actions required in the following Maintenance Action section.\n\n\t\t\t(e)\tWithin 72 hours, even if no further ?FLAPS FAIL' messages have been indicated, perform the actions required in the following Maintenance Action section.\n\n\t\t4.\tIf there is evidence of twisting, skewing, or abnormal deformation, PRIOR TO FURTHER FLIGHT, perform the actions required in the following Maintenance Action section.\n\nMaintenance Action\n\nWhenever the outboard flap position indicator is outside the "GO" range as shown in Figure 2, or whenever directed to do so by the Maintenance Procedure above, perform the following procedures:\n\nA.\tInterrogate the flap electronic control unit (FECU) per Fault Isolation Manual, Section 27-50-00, ?Flaps Fault Isolation,' and rectify as applicable.\n\nB.\tVisually check each flap for evidence of twisting, skewing, or abnormal deformation.\n\n\t\t1.\tIf there is no evidence of twisting, skewing, or abnormal deformation, manually isolate any jammed, disconnected, or dragging component; and rectify all discrepant conditions.\n\n\t\t2.\tIf there is evidence of twisting, skewing, or abnormal deformation, replace both actuators and any discrepant flap panel with new or serviceable components. In addition, inspect flexible shaft(s) inboard of the most outboard actuator removed for discrepancies, and replace any discrepant flexible shaft with a new or serviceable flexible shaft.\n\t\tNote: An acceptable procedure for testing the flap drive breakaway input torque is detailed in Aircraft Maintenance Manual Temporary Revision 27-203, Task 27-53-00-750-802, dated July 17, 1998.\n\nC.\tWithin 3 days after identifying a flap panel twist or logging a ?FLAPS FAIL' caution message, notify Bombardier Aerospace, via the Canadair Regional Jet Action Center, of all findings and actions taken."\n\n\t(c)\tAn 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, New York Aircraft Certification Office (ACO), FAA, Engine and Propeller Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector or FAA Principal Operations Inspector, who may add comments and then send it to the Manager, New York ACO.\n\n\tNOTE 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the New York ACO.\n\n\t(d)\tSpecial 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.\n\n\tNOTE 4: The subject of this AD is addressed in Canadian airworthiness directive CF-98-14, dated July 6, 1998.\n\n\t(e)\tThis amendment becomes effective on October 2, 1998.

Transport Canada Aviation (TCA), which is the airworthiness authority for Canada, recently notified the FAA that an unsafe condition may exist on certain Bombardier Model CL-600-2B19 (Regional Jet Series 100) series airplanes. TCA advises that a number of failures of the flap system resulted in a twisted outboard flap panel. These failures of the flap system were attributed to an internal fault within the Number 3 flap actuator (the inboard actuator on the outboard flap). One report indicated that a twisted flap was not detected prior to take-off, and another report indicated that a twisted flap occurred upon deployment of the flaps for landing. However, in both of these cases, the airplane was controllable and landed successfully.\n\n\tSuch an internal fault within the Number 3 actuator, if not corrected, could cause an unannunciated failure of the flap system, which could result in a flap asymmetry, and consequent reduced controllability of the airplane. (An annunciated failure of the flap system is normally displayed on the engine indicating and crew alert system (EICAS)).\n\n\tTCA has issued Canadian airworthiness directive (AD) CF-98-14, dated July 6, 1998, in order to assure the continued airworthiness of these airplanes in Canada. That AD describes procedures for amending the Limitations, Normal Procedures, and Abnormal Procedures sections of the Airplane Flight Manual (AFM). That AD also describes maintenance procedures and includes two figures that provide information for the normal/abnormal outboard flap configuration in take-off position, and the outboard flap go/no-go criteria in take-off position.\n\nOther Relevant Proposed Rule\n\tThe FAA has previously issued notice of proposed rulemaking (NPRM) Rules Docket 98-NM-134-AD, applicable to certain Bombardier Model CL-600-2B19 (Regional Jet Series 100) series airplanes, which was published in the Federal Register on June 8, 1998 (63 FR 31140). That action proposed to require repetitive inspections of the inboard and outboard flap actuators to measure the rotational freedom of the actuator ball screw adjacent to the actuator housing, and replacement of the flap actuators with new or serviceable actuators, if necessary. \n\nFAA's Determination/Interim Action\n\tThe FAA has determined that the actions proposed by the NPRM described previously are inadequate to preclude an unannunciated failure of the flap system, which could result in a flap asymmetry, and consequent reduced controllability of the airplane. Therefore, in light of the reports described previously, the FAA has determined that the actions required by this AD are necessary to provide interim action to prevent an unannunciated failure of the flap system until final action is identified, at which time the FAA may consider further rulemaking.\n\nFAA's Conclusions\n\tThis airplane model is manufactured in Canada 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. Pursuant to this bilateral airworthiness agreement, TCA has kept the FAA informed of the situation described above. The FAA has examined the findings of TCA, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.\n\nExplanation of Requirements of Rule\n\tSince an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design registered in the United States, this AD is being issued to prevent an unannunciated failure of the flap system, which could result in a flap asymmetry, and consequent reduced controllability of the airplane. This AD requires revising the Limitations, Normal, and Abnormal Procedures sections of the FAA-approved AFM to provide the flight crew with revised procedures for checking the flap system. This action also requires revising the maintenance program to provide revised procedures for checking the flap system, and performing follow-on actions, if necessary.\n\nDifferences Between This AD and the Canadian Airworthiness Directive\n\tOperators should note the following differences between this AD and the Canadian airworthiness directive:\n\n\t\tThis AD further clarifies the personnel who are responsible for certain actions for checking the flap system or performing maintenance.\n\n\t\tA note in the Canadian airworthiness directive specifies that an acceptable procedure for testing of the flap drive breakaway input torque is detailed in Bombardier Service Letter RJ-SL-002A. However, a note in paragraph (b) of this AD specifies that such a procedure is detailed in Aircraft Maintenance Manual Temporary Revision 27-203, Task 27-53-00-750-802, dated July 17, 1998.\n\n\t\tA requirement has been added to paragraph (a)(3) of this AD to specify that any abnormal flap control event should be recorded in the Aircraft Maintenance Log Book. \n\n\t\tThe view that is specified in NOTE 2. of the Appendix (Part 2) of the Canadian airworthiness directive for the outboard flap go/no-go criteria in take-off position has been further clarified in Figure 2 of this AD. \n\nDetermination of Rule's Effective Date\n\tSince 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. \n\nComments Invited\n\tAlthough 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 Docketnumber 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. \n\n\tComments 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. \n\n\tCommenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 98-NM-236-AD." The postcard will be date stamped and returned to the commenter.\n\nRegulatory Impact\n\tThe 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.\n\n\tThe FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it 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."\n\nList of Subjects in 14 CFR Part 39\n\tAir transportation, Aircraft, Aviation safety, Safety.\n\nAdoption of the Amendment\n\tAccordingly, 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: \n\nPART 39 - AIRWORTHINESS DIRECTIVES\n\t1. The authority citation for part 39 continues to read as follows:\nAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\n§ 39.13 (Amended)\n\t2. Section 39.13 is amended by adding the following new airworthiness directive: