Narrative:

As flight neared destination; indications via the annunciator panel indicated a growing problem with the main hydraulic system including hydraulic levels (interment light display); illumination of left main 'hyp pump' light; intermittent activation of the auxiliary hydraulic pump to compensate for fluctuating main hydraulic pressure and intermittent illumination of right 'hyd pump' light. Aircraft QRH was consulted by captain sitting in right seat as pilot not flying and appropriate section referenced indicating only crew action necessary was to 'monitor' pressure. There was no requirement per the QRH for landing as soon as practical or possible; so flight continued toward the destination. At one point; perhaps 30-35 minutes out; the 'hyd level' light illuminated on the annunciator panel indicating to the crew a worsening problem with the main hydraulic system. Prior to this; the crew decided to divert to the nearby international airport since the runways were longer and more services were available rather than continue to the flight's destination. Once the 'hyd level' light illuminated and believing the aircraft was experiencing what would become a total loss of main hydraulic pressure/system and given this was a part 135 passenger-carrying flight; the captain; in consult with the first officer; declared an emergency and so notified center in order to receive priority handling. Center acknowledged and cleared the aircraft direct. The hydraulic system did not worsen from that point; there was no total loss of any aircraft hydraulic system; the aircraft's auxiliary hydraulic system performed as designed and intended and the landing; roll-out; braking and taxi-in were normal. There was no aircraft damage; crew or passenger injuries. Aircraft was followed by emergency vehicles to parking at the FBO and shut down. Passengers disembarked to their final destinations and the aircraft was turned over to maintenance.

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Original NASA ASRS Text

Title: IAI1125 Captain experiences a main hydraulic system leak in cruise and elects to divert to an airport with longer runways. The main system continued to function normally throughout the approach and landing with a low quantity indication.

Narrative: As flight neared destination; indications via the annunciator panel indicated a growing problem with the main hydraulic system including hydraulic levels (interment light display); illumination of left main 'Hyp Pump' light; intermittent activation of the auxiliary hydraulic pump to compensate for fluctuating main hydraulic pressure and intermittent illumination of right 'Hyd Pump' light. Aircraft QRH was consulted by Captain sitting in right seat as Pilot Not Flying and appropriate section referenced indicating only crew action necessary was to 'monitor' pressure. There was no requirement per the QRH for landing as soon as practical or possible; so flight continued toward the destination. At one point; perhaps 30-35 minutes out; the 'Hyd Level' light illuminated on the annunciator panel indicating to the crew a worsening problem with the main hydraulic system. Prior to this; the crew decided to divert to the nearby international airport since the runways were longer and more services were available rather than continue to the flight's destination. Once the 'Hyd Level' light illuminated and believing the aircraft was experiencing what would become a total loss of main hydraulic pressure/system and given this was a Part 135 passenger-carrying flight; the Captain; in consult with the First Officer; declared an emergency and so notified Center in order to receive priority handling. Center acknowledged and cleared the aircraft direct. The hydraulic system did not worsen from that point; there was no total loss of any aircraft hydraulic system; the aircraft's auxiliary hydraulic system performed as designed and intended and the landing; roll-out; braking and taxi-in were normal. There was no aircraft damage; crew or passenger injuries. Aircraft was followed by emergency vehicles to parking at the FBO and shut down. Passengers disembarked to their final destinations and the aircraft was turned over to Maintenance.

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.