What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
On may 17, 2016, this office was notified by jet aviation flight services, kkva, through the submission of their operational irregularity report, that N405LA had experienced a loss of cabin pressure in cruise flight @ FL410 on may 16, 2016. The aircraft was en-route from kvny to kteb on a CFR part 91 repositioning flight, and declared an emergency with landing at kapa (Denver). The masks automatically deployed and the aircraft made an uneventful landing. Maintenance records indicate that the aircraft was in for servicing on may 12, 2016, at thornton aircraft company, T2CR294J, located in van nuys, CA. One of the discrepancies worked at that time was reported as an "aft compartment oil leak", reference thornton wo # MX-10360, squawk 4.3. The corrective action reads as follows: "complied with detailed visual inspection of APU, engines bleed air, and air cycle systems components and ducting. Found small amount of residual oil in water separator below coalescer. Inspected upstream of water separator. No leak source detected. Cleaned ducting and bleed air components. Replaced coalescer and seals and bonding strip, reinstalled all components. Complied with engine, APU runs and environmental systems ops check. Complied with leak checks of bleed air components and ducting. No discrepancies noted. No further action required at this time. Ref: amm 21-10-87." After the aircraft incident, on may 18, 2016, the aircraft was troubleshot and repaired by west star aviation, PAZR068H. West star was able to duplicate the discrepancy and found a loose duct to the cooling turbine, located in the aft compartment. The duct was reconnected and a satisfactory operational check of the pressurization control system and leak check of air conditioning ducting, pressurized at 8 PSI. Jet aviation flight services elected to have the cooling turbine discharge duct replaced, along with the flex sleeves and associated hardware. Leak check was conducted again with positive results and the aircraft was returned to service on may 20, 2016.
As the FAA filed it
ON MAY 17, 2016, THIS OFFICE WAS NOTIFIED BY JET AVIATION FLIGHT SERVICES, KKVA, THROUGH THE SUBMISSION OF THEIR OPERATIONAL IRREGULARITY REPORT, THAT N405LA HAD EXPERIENCED A LOSS OF CABIN PRESSURE IN CRUISE FLIGHT @ FL410 ON MAY 16, 2016. THE AIRCRAFT WAS EN-ROUTE FROM KVNY TO KTEB ON A CFR PART 91 REPOSITIONING FLIGHT, AND DECLARED AN EMERGENCY WITH LANDING AT KAPA (DENVER). THE MASKS AUTOMATICALLY DEPLOYED AND THE AIRCRAFT MADE AN UNEVENTFUL LANDING. MAINTENANCE RECORDS INDICATE THAT THE AIRCRAFT WAS IN FOR SERVICING ON MAY 12, 2016, AT THORNTON AIRCRAFT COMPANY, T2CR294J, LOCATED IN VAN NUYS, CA. ONE OF THE DISCREPANCIES WORKED AT THAT TIME WAS REPORTED AS AN "AFT COMPARTMENT OIL LEAK", REFERENCE THORNTON WO # MX-10360, SQUAWK 4.3. THE CORRECTIVE ACTION READS AS FOLLOWS: "COMPLIED WITH DETAILED VISUAL INSPECTION OF APU, ENGINES BLEED AIR, AND AIR CYCLE SYSTEMS COMPONENTS AND DUCTING. FOUND SMALL AMOUNT OF RESIDUAL OIL IN WATER SEPARATOR BELOW COALESCER. INSPECTED UPSTREAM OF WATER SEPARATOR. NO LEAK SOURCE DETECTED. CLEANED DUCTING AND BLEED AIR COMPONENTS. REPLACED COALESCER AND SEALS AND BONDING STRIP, REINSTALLED ALL COMPONENTS. COMPLIED WITH ENGINE, APU RUNS AND ENVIRONMENTAL SYSTEMS OPS CHECK. COMPLIED WITH LEAK CHECKS OF BLEED AIR COMPONENTS AND DUCTING. NO DISCREPANCIES NOTED. NO FURTHER ACTION REQUIRED AT THIS TIME. REF: AMM 21-10-87." AFTER THE AIRCRAFT INCIDENT, ON MAY 18, 2016, THE AIRCRAFT WAS TROUBLESHOT AND REPAIRED BY WEST STAR AVIATION, PAZR068H. WEST STAR WAS ABLE TO DUPLICATE THE DISCREPANCY AND FOUND A LOOSE DUCT TO THE COOLING TURBINE, LOCATED IN THE AFT COMPARTMENT. THE DUCT WAS RECONNECTED AND A SATISFACTORY OPERATIONAL CHECK OF THE PRESSURIZATION CONTROL SYSTEM AND LEAK CHECK OF AIR CONDITIONING DUCTING, PRESSURIZED AT 8 PSI. JET AVIATION FLIGHT SERVICES ELECTED TO HAVE THE COOLING TURBINE DISCHARGE DUCT REPLACED, ALONG WITH THE FLEX SLEEVES AND ASSOCIATED HARDWARE. LEAK CHECK WAS CONDUCTED AGAIN WITH POSITIVE RESULTS AND THE AIRCRAFT WAS RETURNED TO SERVICE ON MAY 20, 2016.