Narrative:

After an hour into the flight at FL390, we lost all pressurization and started a descent and regained pressurization at FL360 and asked ATC for FL350 to remain there to see if the pressurization problem was going to stop. Pressurization was regained by resetting the mod valve circuit breaker. During engine start (flight originated in tncm (st maarten)) the aircraft went into emergency pressurization and was regained by setting circuit breaker, so when en route, this was done again to see if pressurization would return, and it did. Approximately 5 mins went by and pressurization was lost again. We got cabin altitude light and emergency pressurization almost simultaneously (in about 10 seconds) and aircraft started filling up with a lot of smoke in cabin and started coming into the cabin. It had a slight smell to it, and thought the amount of smoke was excessive when in emergency pressurization. We thought there could have been something starting to burn in back baggage compartment. We were over the atlantic ocean 150 mi from land. The closest airport was mbgm (grand turk). The captain declared an emergency and we asked to be diverted to grand turk airport. We started our emergency descent and ran the cabin/cockpit smoke fire and fumes checklist, and headed for grand turk. The aircraft was not responsive to bleed air switch movement and couldn't reset the aircraft to normal pressurization. It remained in emergency pressurization. With the heat and smoke we just wanted to get the aircraft on the ground. We descended to a lower altitude where pressurization was not required. After recycling switches over and over again, as well as circuit breakers, the aircraft finally responded to shutting off emergency pressurization by placing bleed air switches off (after several attempts). We continued on to grand turk airport unpressurized with no further incidents. We obtained a ferry permit from the FAA to ferry the plane to proventiales airport for a fuel stop and went from there (mbpv) to fll, fl, where the airplane received maintenance on the pressurization system. Callback conversation with reporter revealed the following information: the reporter said that she was flying an LR35A and the electrical smoke was caused by some improperly crimped wires. These also caused the pressurization system to intermittently fail. She said that the maintenance personnel were unsure if the wires were damaged during the manufacturing process or later. She also said that she had not seen the circuit breaker reset procedure for the pressurization system before.

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Original NASA ASRS Text

Title: AN LR35 FLC ON A PART 135 PAX FLT HAS AN ELECTRICAL PROB RESULTING IN A LOSS OF PRESSURIZATION AND SMOKE IN THE ACFT.

Narrative: AFTER AN HR INTO THE FLT AT FL390, WE LOST ALL PRESSURIZATION AND STARTED A DSCNT AND REGAINED PRESSURIZATION AT FL360 AND ASKED ATC FOR FL350 TO REMAIN THERE TO SEE IF THE PRESSURIZATION PROB WAS GOING TO STOP. PRESSURIZATION WAS REGAINED BY RESETTING THE MOD VALVE CIRCUIT BREAKER. DURING ENG START (FLT ORIGINATED IN TNCM (ST MAARTEN)) THE ACFT WENT INTO EMER PRESSURIZATION AND WAS REGAINED BY SETTING CIRCUIT BREAKER, SO WHEN ENRTE, THIS WAS DONE AGAIN TO SEE IF PRESSURIZATION WOULD RETURN, AND IT DID. APPROX 5 MINS WENT BY AND PRESSURIZATION WAS LOST AGAIN. WE GOT CABIN ALT LIGHT AND EMER PRESSURIZATION ALMOST SIMULTANEOUSLY (IN ABOUT 10 SECONDS) AND ACFT STARTED FILLING UP WITH A LOT OF SMOKE IN CABIN AND STARTED COMING INTO THE CABIN. IT HAD A SLIGHT SMELL TO IT, AND THOUGHT THE AMOUNT OF SMOKE WAS EXCESSIVE WHEN IN EMER PRESSURIZATION. WE THOUGHT THERE COULD HAVE BEEN SOMETHING STARTING TO BURN IN BACK BAGGAGE COMPARTMENT. WE WERE OVER THE ATLANTIC OCEAN 150 MI FROM LAND. THE CLOSEST ARPT WAS MBGM (GRAND TURK). THE CAPT DECLARED AN EMER AND WE ASKED TO BE DIVERTED TO GRAND TURK ARPT. WE STARTED OUR EMER DSCNT AND RAN THE CABIN/COCKPIT SMOKE FIRE AND FUMES CHKLIST, AND HEADED FOR GRAND TURK. THE ACFT WAS NOT RESPONSIVE TO BLEED AIR SWITCH MOVEMENT AND COULDN'T RESET THE ACFT TO NORMAL PRESSURIZATION. IT REMAINED IN EMER PRESSURIZATION. WITH THE HEAT AND SMOKE WE JUST WANTED TO GET THE ACFT ON THE GND. WE DSNDED TO A LOWER ALT WHERE PRESSURIZATION WAS NOT REQUIRED. AFTER RECYCLING SWITCHES OVER AND OVER AGAIN, AS WELL AS CIRCUIT BREAKERS, THE ACFT FINALLY RESPONDED TO SHUTTING OFF EMER PRESSURIZATION BY PLACING BLEED AIR SWITCHES OFF (AFTER SEVERAL ATTEMPTS). WE CONTINUED ON TO GRAND TURK ARPT UNPRESSURIZED WITH NO FURTHER INCIDENTS. WE OBTAINED A FERRY PERMIT FROM THE FAA TO FERRY THE PLANE TO PROVENTIALES ARPT FOR A FUEL STOP AND WENT FROM THERE (MBPV) TO FLL, FL, WHERE THE AIRPLANE RECEIVED MAINT ON THE PRESSURIZATION SYS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR SAID THAT SHE WAS FLYING AN LR35A AND THE ELECTRICAL SMOKE WAS CAUSED BY SOME IMPROPERLY CRIMPED WIRES. THESE ALSO CAUSED THE PRESSURIZATION SYS TO INTERMITTENTLY FAIL. SHE SAID THAT THE MAINT PERSONNEL WERE UNSURE IF THE WIRES WERE DAMAGED DURING THE MANUFACTURING PROCESS OR LATER. SHE ALSO SAID THAT SHE HAD NOT SEEN THE CIRCUIT BREAKER RESET PROC FOR THE PRESSURIZATION SYS BEFORE.

Data retrieved from NASA's ASRS site as of July 2007 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.