Airworthiness Directive · Amendment 39-13886 · Bombardier, Inc. Model DHC-3 Airplanes
Bombardier, Inc. Model DHC-3 Airplanes
This AD affects the Model DHC-3 airplanes, all serial numbers, that are:
(1) Modified with STC number SA3777NM; and
(2) Certificated in any category.
The FAA adopts a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-3 airplanes modified with A.M. Luton's Supplemental Type Certificate (STC) number SA3777NM. This AD requires you to inspect the wiring for the heating blankets on P<INF>3</INF> and P<INF>Y</INF> pneumatic lines and the push-to-test function lights to ensure that they are wired to the correct schematic; replace the circuit breaker switch as applicable; and replace the flight manual supplement currently in use with Revision G, dated March 28, 2001 (incorporates Revision I of Sheet 1 of Drawing 20075, "Electrical System Schematic," dated October 10, 2000). This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Canada. We are issuing this AD to detect and correct wiring installed in accordance with an incorrect drawing, which shows the pneumatic heating blankets to the P<INF>3</INF> and P<INF>Y</INF> pneumatic lines wired in series with the indicator lights, rather than parallel. This can result in reduced current for the heating blankets and loss of pneumatic line heating, which can lead to loss of engine power or reverse propeller overspeed governing protection and ultimately loss of control of the airplane.
To address this problem, you must do the following:
| Actions | Compliance | Procedures |
|---|---|---|
| (1) Inspect the electrical wiring to the P 3 and P Y engine pneumatic line heating blankets and the P 3 heater warning light to determine if they are wired in a parallel configuration. If they are not wired in a parallel configuration, they must be rewired | Inspect within 4 months after January 6, 2005 (the effective date of this AD) or 300 hours time in service (TIS) after January 6, 2005 (the effective date of this AD), whichever occurs first. Rewire prior to further flight after the inspection | Follow the procedures in the A.M. Luton Service Information Letter SIL-00-10-10, revision dated, March 22, 2001. |
| (2) Replace Flight Manual Supplement currently in use with Revision G, dated March 28, 2001. This flight manual revision corrects the drawing error on Revisions G and H of Sheet 1 of the Electrical System Schematic Drawing 20075 by incorporating Revision I of Sheet 1 of Drawing 20075, “Electrical System Schematic,” dated October 10, 2000 | Replace within 4 months after January 6, 2005 (the effective date of this AD) or 300 hours TIS after January 6, 2005 (the effective date of this AD), whichever occurs first | Follow the procedures in the A.M. Luton Service Information Letter SIL-00-10-10, revision dated, March 22, 2001. |
| (i) The owner/operator holding at least a private pilot certificate as authorized by section 43.7 of the Federal Aviation Regulations (14 CFR 43.7) may accomplish the flight manual replacement requirement of this AD | ||
| (ii) Make an entry into the aircraft records showing compliance with this portion of the AD in accordance with section 43.9 of the Federal Aviation Regulations (14 CFR 43.9) | ||
| (3) Inspect circuit breaker switch for heated engine pneumatic lines circuit. If an engine is installed that uses both P 3 and P Y heated pneumatic lines, circuit breaker switch, Part Number (P/N) 20075-3 (5 amp), must be replaced with circuit breaker switch P/N 20075-59 (7.5 amp) | Inspect within 4 months after January 6, 2005 (the effective date of this AD), or 300 hours TIS after January 6, 2005 (the effective date of this AD), whichever occurs first. Replace prior to further flight after the inspection | Follow the procedures in the A.M. Luton Service Information Letter SIL-00-10-10, revision dated, March 22, 2001. |
