Accident Overview
On February 16, 2015, at 1445 central standard time, a Piper PA-31-350 airplane, registration N727SC, experienced a collapse of the nose landing gear followed by the right main landing gear during landing on runway 4R at Chicago Midway International Airport (MDW), Chicago, Illinois. The airplane was conducting a positioning flight under 14 CFR Part 91 from Indianapolis Regional Airport (MQJ), Indianapolis, Indiana, to MDW. Visual meteorological conditions prevailed, and the flight operated under an instrument flight rules flight plan.
The airline transport pilot, who was the sole occupant, reported that the approach and landing were normal. After lowering the landing gear and verifying its extension via cockpit indicators, the pilot touched down, at which point the nose gear collapsed, then the right main gear. The airplane departed the runway surface and came to rest upright.
Damage and Examination
An FAA inspector noted substantial damage to the right wing's forward and aft spars. On March 2, 2015, a National Transportation Safety Board investigator, an FAA inspector, and operator representatives examined the aircraft. The landing gear was extended and secured with straps. The hydraulically actuated, retractable tricycle landing gear system was visually inspected. The hydraulic reservoir in the forward baggage compartment showed no fluid in its sight glass; however, a strip inserted into the opening revealed fluid present. No evidence indicated the hydraulic system was compromised during the accident.
During the examination, electrical power was applied, and the landing gear handle was lowered. Emergency extension was performed, and the landing gear locked into the extended position; the right main inner landing gear door moved up. The left main landing gear door actuator was separated from its door. Due to lack of proper support equipment, a test of normal retraction and extension was not conducted. The examination found no evidence of mechanical malfunctions or failures that would have precluded normal operation.
Maintenance and Hydraulic Fluid
The airplane's most recent annual inspection was completed on October 1, 2014. According to the Airplane Flight Manual (AFM), the hydraulic system fluid level should be checked every 50 hours by positioning the airplane level and viewing the sight glass on the reservoir dome. If fluid is not visible, MIL-H-5606 fluid should be added. The AFM preflight inspection checks do not include verifying the hydraulic fluid level in the sight gauge.
An FAA inspector reported that a Piper technical service representative stated the amount of hydraulic fluid found in the accident airplane would not impact landing gear system operation.