Event Overview
On April 1, 2011, at 1545 eastern daylight time, a Cessna 310F, registration N6781X, operated by a private individual as an instructional flight under 14 CFR Part 91, incurred substantial damage when the nose gear collapsed during the landing rollout at Sanford Orlando International Airport (SFB), Sanford, Florida. The certified flight instructor (CFI) and his private pilot-rated dual student were not injured. Visual meteorological conditions prevailed, and no flight plan was filed. The flight had originated from SFB at 1500.
Sequence of Events
After takeoff, while retracting the landing gear, a loud "bang" was heard. The CFI assumed the noise came from the landing gear doors closing into each other. The gear-up light illuminated, indicating that the landing gear were retracted and the doors closed. The flight returned to SFB for two planned landings: first a touch-and-go and then a full stop. On the first landing, the gear were extended and a gear-down light illuminated; the touch-and-go was conducted without incident. When the gear were extended for the second landing, the gear-down light failed to illuminate. The landing gear were recycled, and the gear light gave a gear-up indication. Another gear extension was attempted, and a gear-down indication was not received. The CFI contacted the SFB tower to request a low fly-by for a visual inspection of the gear position. The tower controller reported that all three gear were down and the airplane was cleared to land. The touchdown on the main gear was normal, but as weight was applied to the nose wheel, the nose gear collapsed.
Examination Findings
The airplane was examined by a Federal Aviation Administration (FAA) inspector under the direction of an NTSB investigator. The airplane was raised using aircraft jacks to take the weight off the wheels. The nose gear shock strut trunnion assembly remained in the compressed position, with approximately one inch of the strut trunnion surface visible. An attempt to retract the nose landing gear was unsuccessful because the strut fork assembly came into contact with the nose landing gear door attachment brackets. The nose strut trunnion was manually extended out of the cylinder until approximately three inches of the piston surface was visible. The nose landing gear assembly was then manually raised into the wheel well area and fully retracted. The nose landing gear strut trunnion reservoir was checked for air pressure and was found to be completely empty of air. The fluid level in the strut trunnion reservoir was very low. There were no signs of fluid leakage around the nose landing gear strut trunnion. A review of the maintenance logbooks did not reveal any prior discrepancies with the nose landing gear assembly.