What happened
During a visual approach to runway 01L, the N292HH experienced an in-flight breakup. Radar data revealed that the aircraft crossed the flight path of a Boeing 7SS landing on parallel runway 01R on two separate occasions. The first intersection occurred at approximately 19:10:48 at an altitude of about 3,900 feet MSL with an airspeed of 158 KCAS. At that same geographic point, the Boeing 737 had passed roughly 2 minutes and 9 seconds earlier at 5,500 feet MSL.
The second intersection occurred at approximately 19:11:25 at an altitude of about 3,300 feet MSL with an airspeed of 183 KCAS. The Boeing 737 had occupied that same point approximately 1 minute and 55 seconds prior at an altitude of 3,900 feet MSL. While the Boeing 737 was on a north-northwesterly heading, N292HH was traveling on a northwesterly heading. Following the second crossing, the aircraft continued west of the Boeing 737's path. The final radar contact with the aircraft was recorded at 19:11:34 at an altitude of 3,128 feet MSL and an airspeed of 183 KCAS, located 0.32 miles west of the Boeing 737's flight path.
The investigation
All wreckage was recovered from a single open field. The investigation found that the left wing, both sides of the stabilator, and portions of the right wing flap and aileron had separated during flight. Examination of the inboard sections of the left and right stabilator and the separated left wing spar at the NTSB Material Laboratory determined that all separations were caused by structural overload.
According to the Pilot's Operating Handbook, the maximum structural cruising speed for the aircraft was 165 KCAS, and the never exceed speed (Vne) was 189 KCAS. The design maneuvering speed (Va) was listed as 132 KCAS at 3,600 pounds and 104 KCAS at 2,230 pounds. At the time of the final radar contact, the aircraft was traveling at 183 KCAS. Weather observations indicated winds from the northeast between 9 and 10 knots.