Caravan Undifferentiated
Flight Crew Commercial
Physiological - Other
Aircraft Equipment Problem Less Severe; Flight Deck / Cabin / Aircraft Event Illness / Injury
Flight Crew Took Evasive Action
Procedure; Environment - Non Weather Related; Human Factors
After landing at about XA:00 the aircraft was immediately unloaded. Freight was standing by for the return flight which was then loaded. A total of 1300lbs. was loaded at about XA:10 including 67kgs of dry ice. The aircraft was then locked up for about an hour until the rest of the day's freight was available. At about XB:15 additional freight of about 400lbs was loaded quickly for departure at XB:30. Again the plane was locked while I went inside to sign and receive paperwork for the flight. I boarded the aircraft and blocked out and ground control advised of an approximately 10 minute delay for takeoff.About two minutes into the delay I noticed that I was breathing more deeply than normal and thought for a moment that I had eaten too much for lunch but in fact I had eaten a rather light lunch about 30 minutes prior to departure. It then came to mind that the plane had been closed up for an hour or so with significant dry ice on board and that the oxygen level might have been affected. I immediately opened the vents and side window. About 4 more minutes into the departure delay my breathing had returned to normal I felt comfortable departing just before departure clearance was received. The next day a similar loading scenario occurred. I decided to use oxygen during taxi-out with vents open and felt no effects like the previous day. It may be of interest to note that this incident occurred on a breezy day making it difficult to keep the cabin door open for ventilation and also that the dry ice was loaded floor to ceiling in zones one and two effectively blocking off the cockpit from the ventilation of the cargo door during the final loading.Also of interest may be that I have many times flown with the maximum allowed 76kgs of dry ice on board with no negative effects however I had not ever left the aircraft locked up for an extended period of time prior to departure. Be aware of the need for ventilation of the cabin; especially the flight deck area when dry ice is loaded and especially if left closed up for a period of time before departure. If this is not possible be sure to have oxygen available!
C208 pilot describes the effects of exposure to a carbon dioxide rich environment when his aircraft is loaded and left closed up for over an hour with 67kgs of dry ice on board. The vents and side window are opened and the symptoms disappear.