Background : The physical environment (noise, temperature & humidity, microwaves, and jet lag) in the cockpit of air-transportation airplane is well known to have adverse effects on flight crew. But due to airplane security reasons and so on, the true environment could not be fully assessed up to now. The object of this study was to measure the status, to examine the effects of the environment, and to suggest the protection from them. Methods : The status except jet lag was measured from the first officer seat in the B747-400/ B737-400/500 cockpit at several flight stage (pre-flight, after engine start, take off, climb, cruise, descent).Jet lag was examined through a flight crew schedule for 45 days. Results: Noise level (74-84 dB), humidity (19%), microwaves (well above the caution and dangerous range), and jet lag (not enough to adjust from flight) were measured. The physical environment was examined which had considerable adverse effects on flight crew. Conclusion : The flight crew should be aware of the status which increase work load and physical load during flight. They must leave the cockpit as much as possible while they are off duty and be isolated from such status during rest.