ROTORCRAFT FLIGHT MANUAL TEMPORARY REVISION FOR 4 AXIS AUTOPILOT OPERATIONS, INTRODUCTION OF.

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1 ALERT SERVICE BULLETIN February 2018 MODEL AFFECTED: SUBJECT: 412EP ROTORCRAFT FLIGHT MANUAL TEMPORARY REVISION FOR 4 AXIS AUTOPILOT OPERATIONS, INTRODUCTION OF. HELICOPTERS AFFECTED: Serial numbers 36550, 36562, 36614, 36648, 36649, 36658, and Serial numbers through subsequent with 4 axis Autopilot kit installed. COMPLIANCE: Within the next 25 flight hours, but no later than 7 days after release of this bulletin. DESCRIPTION: This Alert Service Bulletin introduces a Temporary Rotorcraft Flight Manual Revision for 4-axis Autopilot Flight Control System (AFCS) in-flight operations limitation when Radar Altimeter (Rad-Alt) mode is selected. Bell Helicopter has discovered two issues, both related to the use of RAD-ALT mode coupled to the AFCS. The use of new sensors and display conventions on the 412EPI has produced some additional failure mode considerations and non-intuitive presentations that need to be addressed. These issues are as follow: 1- Annunciation deficiency when RAD-ALT mode is engaged. A misleading coupled indication on Display Unit (DU) Flight Director (FD) status window is provided when flight director modes in addition to RAD-ALT are active under certain conditions such as but not limited to: an autopilot computer failure, manual shutoff of an autopilot, a degradation to SAS operation, or manual selection of SAS. RAD ALT modes can also be initially engaged and coupled in these degraded states. This can lead to lack of recognition by the flight crew that displayed pitch and roll commands are not coupled. Prior convention had been that the system indicates decoupled if one or both controls are decoupled (typically via the AFCS control panel CPL or COLL control). The system is therefore inconsistent in its indication of partially coupled or forced decoupled states leading to possible mode confusion. ASB Page 1 of 3 Approved for public release.

2 2- Un-commanded collective down motion. An un-commanded collective down motion can occur following an onside Air Data Computer (ADC) failure when the RAD-ALT mode is engaged. Vertical velocity determination relies on data from the ADC which is independent of the Flight Control Computers (FCC). If the incontrol FCC fails (the FCC associated with the selected flight director) or the corresponding autopilot is switched off while a RAD-ALT mode is engaged, the system automatically switches control to the other autopilot FCC. However, in the event the ADC associated with the in-control autopilot fails independently, the system does not switch over, and an un-commanded downward collective motion may be induced. As a terminating action to this ASB, Bell Helicopter in a future revision will provide a helicopter system modification to alleviate both mentioned above Rad Alt mode issues. APPROVAL: The engineering design aspects of this bulletin are FAA approved. CONTACT INFO: For any questions regarding this bulletin, please contact: MANPOWER: Bell Helicopter Product Support Engineering - Medium Helicopters Tel: / / psemedium@bh.com Approximately 0.5 man-hours are required to complete this bulletin. This estimate is based on hands-on time and may vary with personnel and facilities available. WARRANTY: There is no warranty credit applicable for parts or labor associated with this bulletin. MATERIAL: None required. Consumable Material: None required. ASB Page 2 of 3 Approved for public release.

3 SPECIAL TOOLS: None required. WEIGHT AND BALANCE: Not affected. ELECTRICAL LOAD DATA: Not affected. REFERENCES: BHT-412-FM-5 Flight Manual. AA Rotorcraft Flight Manual. PUBLICATIONS AFFECTED: BHT-412-FM-5 Flight Manual. AA Rotorcraft Flight Manual. ACCOMPLISHMENT INSTRUCTIONS: 1. Insert the attached Temporary Revisions into the applicable Rotorcraft Flight Manual and inform the flight crews of the change. 2. Make an entry in the helicopter logbook and historical service records indicating compliance with this Alert Service Bulletin. ASB Page 3 of 3 Approved for public release.

4 BHT-412-FM-5 ROTORCRAFT FLIGHT MANUAL TEMPORARY REVISION FOR 4-axis Autopilot Operation (ASB ) This temporary revision provides temporary limitations for the use of coupled RAD ALT mode. Insert these Temporary Revision pages opposite like numbered pages in the basic Flight Manual. DO NOT remove existing pages. DO NOT remove temporary pages until replacement pages are received or temporary pages are canceled. THIS MANUAL SHALL BE IN THE HELICOPTER DURING ALL OPERATIONS COPYRIGHT NOTICE COPYRIGHT 201 BELL HELICOPTER TEXTRON INC. AND BELL HELICOPTER TEXTRON CANADA LTD. ALL RIGHTS RESERVED POST OFFICE BOX 482 FORT WORTH, TEXAS Export Classification C, ECCN EAR99 10 OCTOBER 2014 REVISION 3 7 DECEMBER 2017 TEMPORARY REVISION (TR-3) 2 FEBRUARY 2018

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7 BHT-412-FM-5 LOG OF REVISIONS Original FEB 18 LOG OF PAGES PAGE REVISION NO. PAGE REVISION NO. FLIGHT MANUAL Title... 0 A/B... 0 C/D NOTICE Changed information in this Temporary Revision appears in bold type. All other information is outlined. Export Classification C, ECCN EAR99 B 2 FEB 2018 Temporary Revision (TR-3) A/B

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9 BHT-412-FM-5 LOG OF FAA/ODA* APPROVED REVISIONS Original FEB 18 ORGANIZATION DESIGNATION AUTHORIZATION (ODA) APPROVED DATE BHTI ODA LEAD ADMINISTRATOR ODA SW P.O. BOX 482 FT. WORTH, TX Export Classification C, ECCN EAR99 A/B 2 FEB 2018 Temporary Revision (TR-3) C/D

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11 FAA APPROVED BHT-412-FM HOIST PENALTY REGION Pilot shall know CG at time of hoist operation to determine if CG is within penalty region of Figure 1-7, Hoist CG Envelope. Each hoist operation performed is defined as an extension and retraction of hoist cable while hovering with any weight attached. WARNING THIS PENALTY REGION IS VALID FOR ALL HOIST INSTALLATIONS. OPERATION IN PENALTY REGION AFFECTS AIRWORTHINESS LIMITATIONS OF ROTOR COMPONENTS (BHT-412-MM) NORMAL VFR/IFR Coupled RAD ALT mode (4 axis only) is not approved. Digital AFCS preflight test (Level 1minimum) shall be accomplished prior to first flight of the day or before planned flight into IMC. Flight director coupling (normal modes) is not possible with only one autopilot engaged. Export Classification C, ECCN EAR99 2 FEB 2018 Temporary Revision (TR-3) 1-15

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