AD 2004-20-03 Airworthiness Directives; Bombardier Model DHC-8-101, -102, -103, -106, -201, -202, -301, -311, and -315 Airplanes

Models named: DHC-8-101, -102, -103, -106, -201, -202, -301, -311, -315. Read the applicability below — it usually turns on serial or part numbers too.

All Model DHC-8-101, -102, -103, -106, -201, -202, -301, -311, and -315 airplanes; certificated in any category.

Required as indicated, unless accomplished previously. To prevent reduced aerodynamic smoothness of the wing leading edge de-icer boots and possible reduced stall margin, which could result in a significant increase in stall speeds, leading to a possible stall prior to activation of the stall warning; accomplish the following: Critical Zone Limits and Patch Limits (a) For the purposes of this AD, the “critical zone” and “patch limits” are defined in accordance with paragraphs (a)(1) and (a)(2) of this AD. (1) The wing “critical zone” is the area of the leading edge assemblies that represents 3% of the chord. The critical zone may be found by measuring from the aft edge of a leading edge assembly, going forward on the upper surface and lower surface. The measurements identify the aft limits of the critical zone, as shown in Table 1 of this AD. Table 1.—Limits of Critical Zone [In inches] Spanwise region Measured along lower surface Measured along upper surface YW63.00-YW139.00 13.0 13 1/4 YW202.00-YW288.00 10 1/4 10 1/2 YW288.00-YW326.00 9 1/2 9 3/4 YW326.00-YW405.00 8.0 8 1/4 YW405.00-YW790.00 61/2 6 3/4 YW490.00-YW520.00 (series 300 only) 6 1/4 6 1/2 (2) “Patch limits” regarding the number and size of patches are defined as follows: (i) Three small 1 1/4 × 2 1/2 inch (3.17 × 6.35 centimeters (cm)) patches for each 12-inch square (929.0 square cm). (ii) Two medium 2 1/2 × 5 inch (6.35 × 12.70 cm) patches for each 12-inch square. (iii) One large 5 × 10 inches (12.70 × 25.40 cm) patch for each 12-inch square. (3) “Patch limits” regarding the number or total percentage of patches that may be concentrated together in one area of the wing de-icer boot are defined as follows: The spanwise length of each patch in the critical zone, added together, may be no greater than 62.5% of the total length of the boot. A patch is considered to be in the critical zone if any part of the patch is in the critical zone. Patches may be concentrated together in one area of the boot as long as one patch is not applied over part of another patch; patches may not overlap. Detailed Inspection (b) Within 60 days after the effective date of this AD: Perform a detailed inspection of the wing leading edge de-icer boots to determine if the de-icer boots comply with the patch limits in the wing critical zone as defined in paragraph (a) of this AD. Note 1: For the purposes of this AD, a detailed inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.” (1) If all de-icer boots are within the patch limits in the critical zone, no further action is required by this paragraph. (2) If any de-icer boot exceeds the patch limits in the critical zone, accomplish the corrective actions required by paragraph (c) of this AD. Corrective Actions (c) For airplanes that require corrective actions, as described in paragraph (b)(2) of this AD, do the actions in paragraphs (c)(1) and (c)(2) of this AD. (1) Before further flight after the finding of any de-icer boot that exceeds the patch limits per paragraph (b)(2) of this AD: Insert the contents of Table 2 of this AD in the Limitations Section of the aircraft flight manual (AFM) and advise flightcrews to comply with the performance penalties in Table 2 of this AD. (2) Within 24 months after the effective date of this AD, replace all wing de-icer boots that exceed the patch limits in the critical zone as defined in paragraph (a) of this AD, with new de-icer boots, per paragraph (c)(3) of this AD. Remove the contents of Table 2 of this AD from the AFM, and terminate the requirements to comply with the performance penalties after all replacements are accomplished. Table 2.—Performance Penalties AFM sections AFM limits with de-ice boot patch limits exceeded ( Note: Flap settings as applicable to aircraft model) T/O Speed: Sub-Section 5-2: V 1 , V r & V 2 Add: 5 kt (flap 0°); 5 kt (flap 5°); 5 kt (flap 10°); 5 kt (flap 15°). Final T/O Climb Speed Add: 5 kt (flap 0°). T/O WAT Limit: Sub-Section 5-3: Note: Weight reduction not required when limited by maximum structural weight Subtract: 18 kg, 400 lb. (flap 0°); 90 kg, 200 lb. (flap 5°); No change (flap 10°); No change (flap 15°). T/O Climb: Sub-Section 5-4: 1st Seg. Gradient Subtract: 0.008 (flap 0°); 0.004 (flap 5°); 0.004 (flap 10°); 0.004 (flap 15°). 2nd Seg. Gradient Subtract: 0.005 (flap 0°); 0.002 (flap 5°); 0.002 (flap 10°); 0.002 (flap 15°). Final Seg. Gradient Subtract: 0.009 (flap 0°). T/O Field Length: Sub-Section 5-5: TOR, TOD & ASD Add: 16% (flap 0°); 16% (flap 5°); 16% (flap 10°); 16% (flap 15°). Net T/O Flight Path: Sub-Section 5-6: Ref Gradient Subtract: 0.005 (flap 0°); 0.002 (flap 5°); 0.002 (flap 10°); 0.002 (flap 15°). 4th Seg. Net Gradient Subtract: 0.012 (flap 0°). Flap Retraction Initiation Speed Add: 5 kt (flap 5°); 5 kt (flap 10°); 5 kt (flap 15°). Enroute Climb Data: Sub-Section 5-7: Enroute Climb Speed Add: 5 kt. Net Climb Gradient Subtract: 0.004. OEI-Climb Ceiling Subtract: 1,200 ft. Landing Speed: Sub-Section 5-8: Approach, Go-around & Vref Add: 5 kt (flap 5°); 5 kt (flap 10°); 5 kt (flap 15°); 5 kt (flap 35°). Landing WAT Limit: Sub-Section 5-9: Note: Weight reduction not required when limited by maximum structural weight Subtract: 860 kg, 1,900 lb.(flap 10°); 225 kg, 500 lb. (flap 15°); 180 kg, 400 lb. (flap 35°). Landing Climb Data: Sub-Section 5-10: Approach Gross Climb Gradient Subtract: 0.010 (flap 5°); 0.003 (flap 10°); 0.002 (flap 15°). Balked Landing Gross Climb Gradient Subtract: 0.035 (flap 10°); 0.017 (flap 15°); 0.016 (flap 35°). Landing Field Length: Sub-Section 5-11: Add: 23% (flap 10°); 16% (flap 15°); 10% (flap 35°). Brake Energy: Sub-Section 5-12: Accel/Stop B.E Add: 7% (flap 0°); 7% (flap 5°); 7% (flap 10°); (flap 15°). Landing B.E Add: 30% (flap 10°); 20% (flap 15°); 8% (flap 35°). (3) Do the replacements described in paragraph (c)(2) of this AD per a method approved by either the Manager, Systems and Flight Test Branch, ANE-172, FAA, New York Aircraft Certification Office (ACO), or Transport Canada Civil Aviation (TCCA) (or its delegated agent). The applicable chapter of the applicable Bombardier Aircraft Maintenance Manual (AMM) or in the temporary revision listed in Table 3 of this AD is one approved method. Table 3.—AMM Reference Model AMM Product support manual (PSM) Chapter Temporary revision (TR) Date DHC-8-101, -102, -103, and -106 Series 100 1-8-2 30-10-48 TR 30-35 October 28, 2003. DHC-8-201, and -202 Series 200 1-82-2 30-12-00 TR 30-025 August 28, 2003. DHC-8-301, -311, and -315 Series 300 1-83-2 30-10-48 TR 30-25 October 21, 2003. Parts Installation (d) As of the effective date of this AD, no person may install—on any airplane—a de-icer boot patch in the critical zone of the wing de-icer boots that exceeds the patch limits specified in paragraph (a) of this AD. Actions Accomplished Previously (e) Actions that were accomplished before the effective date of this AD per the applicable chapters of the following AMMs is acceptable for compliance with the corresponding action in this AD: DHC-8-101, -102, and -106 Series 100 AMM, PSM 1-8-2, Chapter 30-10-48, Revision 49, dated October 3, 2001; DHC-8-201, and -202 Series 200 AMM, PSM 1-82-2, Chapter 30-12-00, Revision 11, dated October 19, 2001; and Temporary Revision 30-21 to the DHC-8-301, -311, and -315 Series 300 AMM, PSM 1-83-2, Chapter 30-10-48, dated October 30, 2001. Alternative Methods of Compliance (f) In accordance with 14 CFR 39.19, the Manager, New York ACO, FAA, is authorized to approve alternative methods of compliance for this AD. Note 2: The subject of this AD is addressed in Canadian airworthiness directive CF-2001-43, dated November 23, 2001. Effective Date (g) This amendment becomes effective on November 3, 2004. Issued in Renton, Washington, on September 16, 2004. Ali Bahrami, Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 04-21646 Filed 9-28-04; 8:45 am] BILLING CODE 4910-13-P