From the FAA’s Accident/Incident Data System (AIDS), through its Aviation Safety Information Portal, as reported. The NTSB investigates accidents separately, and its record of an accident is the fuller one. The aircraft is matched to the registry by N-number and event date, checked against the reported make and model; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(-23) On taxi for takeoff aircrew heard a loud hissing sound from aft section of the aircraft. Aircrew taxied back to ramp area. PIC became incapacitated. SIC parked aircraft, shut down engines, and while trying to egress from main door, became incapacitated and collapsed on the aircraft floor. During inspection of the aircraft nine to ten cylinders were found unsecured (no cargo strip installed) by the cargo door, another two cylinders were laying on the aircraft floor (perpendicular with the fuselage) and another nine to ten cylinders were standing in a rack with a single cargo strip around them in zone 4 of the aircraft. Five of these cylinders did not have the safety covers installed on them. Of the five cylinders without their safety covers installed standing in the rack, four had their valves securely closed and contained compressed gas. The fifth cylinder's valve was open about half to one full turn and its contents had been expended.
As the FAA filed it
(-23) ON TAXI FOR TAKEOFF AIRCREW HEARD A LOUD HISSING SOUND FROM AFT SECTION OF THE AIRCRAFT. AIRCREW TAXIED BACK TO RAMP AREA. PIC BECAME INCAPACITATED. SIC PARKED AIRCRAFT, SHUT DOWN ENGINES, AND WHILE TRYING TO EGRESS FROM MAIN DOOR, BECAME INCAPACITATED AND COLLAPSED ON THE AIRCRAFT FLOOR. DURING INSPECTION OF THE AIRCRAFT NINE TO TEN CYLINDERS WERE FOUND UNSECURED (NO CARGO STRIP INSTALLED) BY THE CARGO DOOR, ANOTHER TWO CYLINDERS WERE LAYING ON THE AIRCRAFT FLOOR (PERPENDICULAR WITH THE FUSELAGE) AND ANOTHER NINE TO TEN CYLINDERS WERE STANDING IN A RACK WITH A SINGLE CARGO STRIP AROUND THEM IN ZONE 4 OF THE AIRCRAFT. FIVE OF THESE CYLINDERS DID NOT HAVE THE SAFETY COVERS INSTALLED ON THEM. OF THE FIVE CYLINDERS WITHOUT THEIR SAFETY COVERS INSTALLED STANDING IN THE RACK, FOUR HAD THEIR VALVES SECURELY CLOSED AND CONTAINED COMPRESSED GAS. THE FIFTH CYLINDER'S VALVE WAS OPEN ABOUT HALF TO ONE FULL TURN AND ITS CONTENTS HAD BEEN EXPENDED.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.