Applicability:
Shadin ADC-2000 air data computers (ADC), part numbers (P/N)
962830A-1-S-8, 962830A-2-S-8 or 962830A-3-S-8, Configurations B, C
and D.
Note 1: ADC-2000 ADCs are known to be installed in, but not
limited to, the following aircraft:
Alliance Aircraft Group, LLC
H-250
B-N Group Ltd
BN2A
Bombardier Inc
DHC-3, DHC-6
Cessna Aircraft Company
172, 180, 180E, 185, 206, 206E, 206F, 206G 208, 210L, 310
de Havilland Inc
DHC-2
The New Piper Aircraft, Inc
PA-28-180, PA-28-181, PA-31-350, PA-32-300, PA-32-301, PA-32R-300,
PA-34-200T
Requirement: 1. Perform a pre-flight check in
accordance with Paragraph E - Interim Procedures of Shadin Service
Bulletin SB28–05–002, Rev C, dated 29 June 2005 to
ensure the ADC and the Electronic Flight Information System (EFIS)
altimetry accuracy (ie the altitudes, altimeter and elevation do
not differ by more than 75 feet).
Requirement 1 may be performed by pilot, other than a student
pilot, endorsed on the type. The requirement to perform a
pre-flight check in accordance with this Directive is to be entered
on the Maintenance Release in the Maintenance Required Section and
compliance is to be certified before each flight.
2. If, as a result of the Requirement 1 check, the required
altimetry accuracy is not confirmed, install a placard with letters
at least 6mm (0.25 in) high in clear view of the pilot stating:
"FLIGHT IN IMC OR UNDER IFR NOT PERMITTED"
3. Return all affected ADCs to the Shadin Repair Facility for
upgrade.
Note 2: Contact the Shadin Technical Support Department for a
Return Merchandise Authorization (RMA) number before returning the
ADC.
Until the ADC-2000 is modified, returned and reinstalled, the
aeroplane may only be flown if minimum equipment requirements for
that aeroplane are still met. Once the upgraded ADC has been
reinstalled the Requirement 2 placard may be removed.
4. Shadin ADC-2000, P/N 962830A-1-S-8, 962830A-2-S-8 or
962830A-3-S-8, Configurations B, C, and D, may not be installed on
any aeroplane either as an initial installation or as a replacement
spare unless it has been upgraded as specified in Requirement
2.
Note 3: FAA AD 2005-25-08 Amdt 39-14401 refers.
Compliance:
For Requirement 1 - Within the next 25 hours time-in-service (TIS)
the effective date of this Directive and thereafter before each
flight until the ADC is upgraded as specified Requirement 3.
For Requirement 2 - Before further flight after the ADC fails the
Requirement 1 altimetry accuracy check.
For Requirement 3 - Within 15 months after the effective date of
this Directive.
For Requirement 4 - As of the effective date of this Directive.
This Airworthiness Directive becomes effective on 23 January
2006.
Background: The United States FAA has received
reports that certain ADC-2000 units display incorrect altitude
information on the EFIS to the pilot. The display of incorrect
altitude could cause the flight crew to react to this incorrect
flight information and possibly result in an unsafe operating
condition.