Applicability:
Learjet Model 45 aeroplanes, serial numbers (S/N) 45-005 through
45-273 inclusive and 45-2001 through 45-2029 inclusive.
Requirement: 1. Modify the electrical wire
bundle for the alternator on the left- hand engine and perform a
general visual inspection of the left and right engines to make
sure that the proper clearances are maintained between all wiring
harnesses and engine tubing. All actions are to be carried out in
accordance with the Accomplishment Instructions of the applicable
Bombardier Alert Service Bulletin (ASB) as follows:
Aeroplane S/N Range
45-2001 through 45-2029 inclusive
45-005 through 45-273 inclusive
ASB
SB A40-71-01, dated 29 September 2005
SB A45-71-4, dated 29 September 2005
Note 1: For the purposes of this Directive, a general visual
inspection is defined as "A visual examination of an interior or
exterior area, installation or assembly to detect obvious damage,
failure or irregularity. This level of inspection is made from
within touching distance unless otherwise specified. A mirror may
be necessary to ensure visual access to all surfaces in the
inspection area. This level of inspection is made under normally
available lighting conditions such as daylight, hangar lighting,
flashlight or droplight and may require removal or opening of
access panels or doors. Stands, ladders or platforms may be
required to gain proximity to the area being checked."
2. Correct improper clearances detected during the Requirement 1
inspection in accordance with the applicable ASB.
3. For aeroplanes with serial numbers identified below, replace the
fuses for the hydraulic shutoff valves with fuses having higher
amperage in accordance with the Accomplishment Instructions of the
following applicable Bombardier Service Bulletin (SB):
Aeroplane S/N Range
45-2001 through 45-2015 inclusive
45-005 through 45-254 inclusive
SB
SB 40-24-01, dated 22 April 2005
SB 45-24-6, dated 22 April 2005
Later revisions of the above SBs, approved by the United States
Federal Aviation Administration (FAA) as an Alternate Method of
Compliance (AMOC) to FAA AD 2005-24-13, are considered acceptable
for compliance with the equivalent Requirements of this
Directive.
Note 2: FAA AD 2005-24-13 Amdt 39-14393 refers.
Compliance: For Requirement 1 - Within 50 hours
time in service after the effective date of this Directive.
For Requirement 2 - Before further flight after completing the
Requirement 1 inspection.
For Requirement 3 - Concurrent with or prior to completing
Requirement 1.
This Airworthiness Directive becomes effective on 20 December
2005.
Background:
The FAA has received a report of a fire in the left-hand engine
nacelle. Investigation revealed that an electrical wire bundle for
the engine alternator had chafed a hole in a hydraulic line. This
condition, if not corrected, could result in a fire in the engine
nacelle.
This Directive requires modification of the electrical wire
bundle for the alternator on the left-hand engine, inspecting for
clearance between wire harnesses and engine tubing for each engine
together with any necessary corrective actions. The Directive also
requires, on some aeroplanes, the replacement of the fuses for the
hydraulic shutoff valves with fuses having higher amperage.