AD/PC-12/55 Adahrs Incorrect Data (Cth)

AIRWORTHINESS DIRECTIVE

For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.001(1) of CASR 1998.  The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

Pilatus PC-12 Series Aeroplanes

AD/PC-12/55 ADAHRS - Incorrect Data 4/2009 TX

Applicability:

Model PC-12/47E aeroplanes with Manufacturer Serial Number (MSN) 545 and from MSN 1001 and up.

Requirement:

Unless previously accomplished, amend the PC-12/47E Pilot’s Operating Handbook (POH) Report No 02277 as follows:

Insert the following limitation in Section 2 – Limitations:

Maximum bank angle during climb should not exceed 30 degrees.

Insert the following information in Section 3A – Abnormal Procedures:

When a discrepancy is observed between the Primary Flight Display (PFD) and the Electronic Standby Instrument System (ESIS), the aircraft should be flown with Flight Director (FD) and Auto Pilot (AP) engaged until the error corrects itself.  The ESIS should be used as the primary means of attitude reference as long as the problem exists.  If the problem does not disappear after 15 minutes, transition to VMC conditions for the rest of the flight is required.

Insert the following information in Section 4 – Normal Procedures:

The FD shall be used for take-off in either heading or navigation mode as appropriate and with the heading or navigation properly set.

The pilot shall include the ESIS in the normal scan.

Incorporation of the POH Temporary Revision No. 9 or a copy of this Directive into the PC-12/47E POH satisfies the requirements of this Directive.

Note:  EASA Emergency AD 2009-0028-E refers.

Compliance:

Prior to the next flight after the effective date of this Directive.

This Airworthiness Directive becomes effective on 13 February 2009.

Background:

The European Aviation Safety Agency (EASA) has advised that field reports have indicated that during take-off with light turbulences or after rapid roll/heading attitude changes soon after take-off, it is possible that both PFDs indicate a roll attitude offset of up to 10 degrees in the same direction.  This condition has been reported to correct itself after several minutes of un-accelerated flight with levelled wings and no sideslip.

This situation, if not corrected, could result in an undesired bank angle which constitutes an unsafe condition.

For the reason described above, this Directive mandates as an interim measure a revision of the operational procedures to be inserted into the POH.

James Coyne
Delegate of the Civil Aviation Safety Authority

12 February 2009