On April 12, 2008, at 1550 Pacific daylight time, a Maule M-5-235C, N9277E, veered off the left side of the runway and nosed over after landing at Firstair Field, Monroe, Washington. The private pilot operated the airplane under the provisions of 14 Code of Federal Regulations Part 91. The pilot and his two passengers were not injured; the airplane was substantially damaged. Visual meteorological conditions prevailed, and no flight plan had been filed. The flight originated at Woodland, Washington, at 1435. The pilot stated that during the landing rollout a moderate right crosswind gust of 7 to 8 knots affected the airplane, causing it to drift left. He applied right rudder to compensate, however, as he applied more and repeated right rudder pressure the airplane continued to drift left. It went off the runway, onto a grass shoulder, then nosed over into the drainage ditch. The pilot stated that the passenger in the copilot's seat was very nervous and tense throughout the flight, and with the sudden left movement of the airplane after landing, he may have tensed up and inadvertently blocked the rudder pedals with his feet. The pilot reported that the airplane and engine had no mechanical failures or malfunctions during the flight.