Airworthiness Directive · Amendment 39-18758 · Hydraulic power
AgustaWestland S.p.A. (Agusta) Helicopters
This AD applies to Agusta Model AB139 and AW139 helicopters, all serial numbers except serial number 31007, 31094, 31293, 31301, 31303, 31313, and 31329, certificated in any category.
We are adopting a new airworthiness directive (AD) for certain Agusta Model AB139 and AW139 helicopters. This AD requires performing operational checks of both hydraulic systems. This AD was prompted by an assessment of the hydraulic systems of the helicopter following an accident. These actions are intended to prevent the unsafe condition on these products.
You are responsible for performing each action required by this AD within the specified compliance time unless it has already been accomplished prior to that time.
Within 50 hours time-in service:
(1) Perform an operational test of each Number 1 and Number 2 power control module (PCM). If the fluid level in the reservoir changes more than 5mm (0.196 in) in an hour, replace the affected PCM.
(2) Perform an operational test of each tail shut-off valve. If the 2 SERVO caution message is not illuminated and the UTIL SOV2 and TR SOV indications are in the open position:
(i) Disconnect the Tail Shutoff valve connector, HP4P1.
(ii) Disconnect the PCM2 connectors, A44P3 and A44P12.
(iii) Disconnect the TB38 terminal board connector, TB38P1.
(iv) Perform a continuity test from HP4P1-1 to A44P12-16, from HP4P1-2 to TB38P1-D, and from HP4P1-4 to A44P3-6.
(v) If there is no continuity, repair or replace the defective wiring.
(vi) If there is continuity, release the test lever of the PCM2 to the DOWN NORM position.
(vii) If the TRSVO indication stays in the closed position, replace the tail shutoff valve.
(3) Perform an operational test of the PCM 2 flight control shut-off valve as described in the Compliance Instructions, paragraphs 5.1. through 5.5., of Agusta Bollettino Tecnico No. 139-269, dated September 30, 2011 (BT 139-269).
(i) If the 2 SERVO caution message is illuminated:
(A) On the hydraulic control panel, lift the guard of the SOV1/SOV2 switch and set it to SOV2 (closed position). Make sure that the 2 HYD PRESS caution message and the HYD 2 PRESS warning light on the hydraulic control panel are illuminated.
(B) Reset the SOV1/SOV2 switch to the open position.
(C) If the 2 HYD PRESS and 2 SERVO caution messages remain illuminated:
(1) Disconnect the PL14P1 and PL14P2 connectors from the hydraulic control panel.
(2) Disconnect the A1-1P4 connector from the MAU1.
(3) Disconnect the A2-1P3 connector from the MAU2.
(4) Disconnect the A44P3 connector from the Number 2 PCM.
(5) Disconnect the PL1P3 connector from the circuit breaker panel.
(6) Perform a continuity test from PL14P1-J to A1-1P4-18, from PL14P1-D to PL1P3-q, from PL14P2-J to A44P3-5, and from PL14P2-T to A2-1P3-34. If there is no continuity, repair or replace the defective wiring.
(7) If the HYD PRESS and 2 SERVO caution messages remain illuminated, replace the number 2 hydraulic power module.
(ii) If the 2 HYD PRESS caution message is illuminated, the HYD 2 pressure indication is more than 190 bar (2,755 lbf/sq in), and the SOV2 shutoff valve is in the open position, replace the pressure switch on the Number 2 PCM.
(iii) If the closure of SOV 2 is indicated on the MFD hydraulic synoptic page, before further flight, replace the Number 2 PCM.
(4) Perform an operational test of the PCM 1 flight control shut-off valve as described in the Compliance Instructions, paragraphs 6.1. through 6.4., of BT 139-269.
(i) If the 1 SERVO caution message is illuminated:
(A) On the hydraulic control panel, lift the guard of the SOV1/SOV2 switch and set it to SOV1 (closed position). Make sure that the 1 HYD PRESS caution message and the HYD 1 PRESS warning light on the hydraulic control panel are illuminated.
(B) Reset the SOV1/SOV2 switch to the open position. If the 1 HYD PRESS and 1 SERVO caution messages remain illuminated:
(1) Disconnect the PL14P1 and PL14P2 connectors from the hydraulic control panel.
(2) Disconnect the A1-1P4 connector from the MAU1.
(3) Disconnect the A2-1P3 connector from the MAU2.
(4) Disconnect the A45P3 connector from the Number 1 PCM.
(5) Disconnect the PL1P3 connector from the circuit breaker panel.
(6) Perform a continuity test from PL14P1-J to A1-1P4-18, from PL14P1-E to A45P3-5, from PL14P1-D to PL1P3-q, and from PL14P2-T to A2-1P3-34. If there is no continuity, repair or replace the defective wiring.
(7) If the HYD PRESS and 1 SERVO caution messages remain illuminated, replace the Number 1 hydraulic control panel.
(ii) If the 1 HYD PRESS caution message is illuminated, the HYD 1 pressure indication is more than 190 bar (2,755 lbf/sq in), and the SOV1 shutoff valve is in the open position, replace the pressure switch on the Number 1 PCM.
(iii) If the closure of SOV 1 is indicated on the MFD hydraulic synoptic page, before further flight, replace the Number 1 PCM.
(4) Perform an operational test of the emergency landing gear shutoff valve as described in the Compliance Instructions, paragraphs 7.1. through 7.4., of BT 139-269.
(i) If the EMERG L/G PRESS caution message is illuminated, the HYD 1 pressure indication is more than 190 bar (2,755 lbf/sq in), and the UTIL SOV1 (LDG GEAR EMER) shutoff valve is in the open position, replace the pressure switch on the Number 1 PCM.
(ii) If the 1 HYD MIN caution message is illuminated, inspect the fluid level on the Number 1 PCM and inspect the Number 1 main hydraulic system for leaks.
(A) If the fluid level is between the FULL and ADD marks, or if there are no hydraulic fluid leaks, perform an operational test of the level switches. If the 1 HYD MIN caution message is illuminated, replace the Number 1 PCM.
(B) If there is a hydraulic fluid leak:
(1) Replace all leaking parts and lines or repair the leak.
(2) If the 1 HYD MIN caution message remains illuminated, perform an operational test of the level switches.
(3) If the 1 HYD MIN caution message remains illuminated, replace the Number 1 PCM.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
