Incident Details
A certified flight instructor (CFI) and a student pilot were performing crosswind landing practice in a Piper PA-28-140. After completing preflight checks, the CFI had difficulty closing the top cabin door latch, eventually managing to lock it. The student pilot then began taxiing the airplane but reported that the brakes felt "weak." The airplane was equipped with toe-brakes only on the pilot side, which the student occupied. The CFI decided to proceed with the flight.
The crew executed three uneventful touch-and-go landings. During the fourth takeoff, the door latch released. The CFI immediately reduced the throttle and instructed the student to apply the brakes. The student complied but reported that the brakes were not working. The CFI then attempted to slow the aircraft by applying the center hand brake but found it ineffective. Applying left rudder in an effort to prevent the airplane from rolling to the end of the runway and beyond the overrun, the airplane departed the runway to the left, struck a drainage ditch, and rolled down an embankment.
Damage
During the accident sequence, the left landing gear separated, and the left wing sustained substantial damage.
Background
According to the Piper PA-28 Cherokee Owner's Handbook, the cabin door is double-latched, reducing the likelihood of it springing open in flight at both top and bottom. However, if the upper latch is forgotten or the lower latch not fully engaged, the door may spring partially open, typically at takeoff or soon after. The handbook notes that an open door does not affect normal flight characteristics and that a normal landing can be made with the door open.
A Federal Aviation Administration (FAA) inspector observed tire skid marks on the runway surface corresponding to the location where the airplane departed the runway.