What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(-23) On 16SEP03, PA-31 N3548B operating as amf 4158 from kvgt to kphx diverted to lkas after the pilot experienced symptoms consonant with carbon monoxide poisoning after leveling off enroute at 11,000 ft MSL. The pilot observed that the chemical spot on the co detector in the airplane had turned from tan to black, indicating the presence of co. after landing, he was taken to hospital as a precaution/for observation; it was determined that detectable levels of co were present in his bloodstream. The aircraft was inspected by amf kphx and local maintenance personnel at klas (including engine runs with both the "chem spot" and an electronic co sniffer in the cockpit), but no evidence of co contamination or immediate explanation for inflight contamination of the cockpit air was found. As a precaution, the heater was disconnected and the airplane ferried to kbur for further evaluation; the ferry pilot was instructed to keep all ventilating air inlets open, direct the cockpit gasper vents at his face, and land if there was any evidence of co contamination. Again with both our standard chemical "dark spot" co detector and the electronic sniffer aboard, there was no indication of co contamination. At bur, it was discovered that the intake tube for the left instrument air pump had come loose and was rubbing on the #1 engine turbocharger exhaust tailpipe. Several small holes had been worn through the tailpipe, and a hole had been worn/melted through the intake tube. We surmise that the air pump was sucking exhaust gasses through the holes, blowing them through the captain's gyro horizon and first officer's gyro horizon and directional gyro, and into the cockpit. Although on lower altitude flights and flights with the air vents open, the co concentration apparently did not get high enough to cause a problem (or darken the "spot" on the co detector in the airplane), the long climb to altitude and operation with the vents shut did so on the day of the incident. The tailpipe, inline air filters, and gyro instruments connected to the airplane's pneumatic system were changed. I conducted a test flight, climbing to 10,000 MSL. During the last 1000 ft of climb, I closed all cockpit air inlets and turned the heater on to the full hot position, leaving it in that condition for two minutes after level-off. There were no indication of co from either the electronic or "dark spot" co detectors. I then returned to kbur. After landing and turning off the runway, I opened the crew door. A gust of crosswind blew exhaust gas from the left engine in through the open door, and the electronic co detector "beeped" - confirming that it was working properly. The airplane was returned to service and has had no reported co problems since.
As the FAA filed it
(-23) ON 16SEP03, PA-31 N3548B OPERATING AS AMF 4158 FROM KVGT TO KPHX DIVERTED TO LKAS AFTER THE PILOT EXPERIENCED SYMPTOMS CONSONANT WITH CARBON MONOXIDE POISONING AFTER LEVELING OFF ENROUTE AT 11,000 FT MSL. THE PILOT OBSERVED THAT THE CHEMICAL SPOT ON THE CO DETECTOR IN THE AIRPLANE HAD TURNED FROM TAN TO BLACK, INDICATING THE PRESENCE OF CO. AFTER LANDING, HE WAS TAKEN TO HOSPITAL AS A PRECAUTION/FOR OBSERVATION; IT WAS DETERMINED THAT DETECTABLE LEVELS OF CO WERE PRESENT IN HIS BLOODSTREAM. THE AIRCRAFT WAS INSPECTED BY AMF KPHX AND LOCAL MAINTENANCE PERSONNEL AT KLAS (INCLUDING ENGINE RUNS WITH BOTH THE "CHEM SPOT" AND AN ELECTRONIC CO SNIFFER IN THE COCKPIT), BUT NO EVIDENCE OF CO CONTAMINATION OR IMMEDIATE EXPLANATION FOR INFLIGHT CONTAMINATION OF THE COCKPIT AIR WAS FOUND. AS A PRECAUTION, THE HEATER WAS DISCONNECTED AND THE AIRPLANE FERRIED TO KBUR FOR FURTHER EVALUATION; THE FERRY PILOT WAS INSTRUCTED TO KEEP ALL VENTILATING AIR INLETS OPEN, DIRECT THE COCKPIT GASPER VENTS AT HIS FACE, AND LAND IF THERE WAS ANY EVIDENCE OF CO CONTAMINATION. AGAIN WITH BOTH OUR STANDARD CHEMICAL "DARK SPOT" CO DETECTOR AND THE ELECTRONIC SNIFFER ABOARD, THERE WAS NO INDICATION OF CO CONTAMINATION. AT BUR, IT WAS DISCOVERED THAT THE INTAKE TUBE FOR THE LEFT INSTRUMENT AIR PUMP HAD COME LOOSE AND WAS RUBBING ON THE #1 ENGINE TURBOCHARGER EXHAUST TAILPIPE. SEVERAL SMALL HOLES HAD BEEN WORN THROUGH THE TAILPIPE, AND A HOLE HAD BEEN WORN/MELTED THROUGH THE INTAKE TUBE. WE SURMISE THAT THE AIR PUMP WAS SUCKING EXHAUST GASSES THROUGH THE HOLES, BLOWING THEM THROUGH THE CAPTAIN'S GYRO HORIZON AND FIRST OFFICER'S GYRO HORIZON AND DIRECTIONAL GYRO, AND INTO THE COCKPIT. ALTHOUGH ON LOWER ALTITUDE FLIGHTS AND FLIGHTS WITH THE AIR VENTS OPEN, THE CO CONCENTRATION APPARENTLY DID NOT GET HIGH ENOUGH TO CAUSE A PROBLEM (OR DARKEN THE "SPOT" ON THE CO DETECTOR IN THE AIRPLANE), THE LONG CLIMB TO ALTITUDE AND OPERATION WITH THE VENTS SHUT DID SO ON THE DAY OF THE INCIDENT. THE TAILPIPE, INLINE AIR FILTERS, AND GYRO INSTRUMENTS CONNECTED TO THE AIRPLANE'S PNEUMATIC SYSTEM WERE CHANGED. I CONDUCTED A TEST FLIGHT, CLIMBING TO 10,000 MSL. DURING THE LAST 1000 FT OF CLIMB, I CLOSED ALL COCKPIT AIR INLETS AND TURNED THE HEATER ON TO THE FULL HOT POSITION, LEAVING IT IN THAT CONDITION FOR TWO MINUTES AFTER LEVEL-OFF. THERE WERE NO INDICATION OF CO FROM EITHER THE ELECTRONIC OR "DARK SPOT" CO DETECTORS. I THEN RETURNED TO KBUR. AFTER LANDING AND TURNING OFF THE RUNWAY, I OPENED THE CREW DOOR. A GUST OF CROSSWIND BLEW EXHAUST GAS FROM THE LEFT ENGINE IN THROUGH THE OPEN DOOR, AND THE ELECTRONIC CO DETECTOR "BEEPED" - CONFIRMING THAT IT WAS WORKING PROPERLY. THE AIRPLANE WAS RETURNED TO SERVICE AND HAS HAD NO REPORTED CO PROBLEMS SINCE.