SA-227 AC Metro III
Situational Awareness
Aircraft Equipment Problem Less Severe; Ground Event / Encounter Loss Of Aircraft Control; Ground Excursion Runway
General None Reported / Taken
Aircraft; Human Factors
Prior to taking runway I ran through the normal before takeoff checklist and proceeded onto the runway after I was cleared for takeoff. I lined up and fully stopped to run the remaining line items of the checklist and then slowly began to apply takeoff power. As soon as I advanced the power levers the aircraft began to veer to the right; I applied opposite brake to attempt bring the aircraft back to center line. The plane continued to veer right; at this point I applied max reverse and maximum braking. The aircraft still continued slowly towards the edge of the runway. The nose wheel dipped off the runway and the aircraft came to a stop. I notified tower of the incident and requested a tow. They inquired if I needed any other assistance (fire trucks); I declined. I proceeded to shut down and secure the engines. Once Airport Ops was on scene; we noticed there were some skid marks from the right main landing gear; indicating a possible brake lock up from the right side. The nose wheel was no more than 8ft from the runway's edge; the main landing gear remained on the tarmac. There was no visible damage to the aircraft; nor was there any property damage. The aircraft was towed back to the hanger. To avoid a recurrence of this event I will be more vigilant in making sure the nose wheel is lined up straight with the center line before applying power; and with power application I will be even more careful. However with a possible brake lock up; I'll attempt to be even quicker at applying maximum braking and reverse thrust.
SA-227AC Captain reported loss of directional control early in the takeoff roll that resulted in a runway excursion. Reporter cited a possible locked brake as a contributing factor.