This March 2008 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
Aircraft: Cessna 210. Injuries: None. Location: Cincinnati, Ohio. Aircraft damage: Substantial.
What reportedly happened: The pilot had not flown the airplane over the winter and the battery had lost its charge. The engine was started with the assistance of ground power. After engine start-up, the alternator output indicated 29 volts, while the battery voltage indicated zero, and the ammeter showed that the battery was charging. The pilot decided to attempt flight. He reported that upon raising the landing gear and flaps after liftoff, all electrical power went out, so he elected to remain in the traffic pattern and return for an immediate landing. He lowered the landing gear handle. However, due to what he perceived as an urgent situation and the attention required by other traffic in the vicinity, he did not use the emergency gear extension procedure to ensure that the landing gear was fully down and locked. Upon touch down, the main landing gear collapsed and the airplane went of the left side of the runway. The left horizontal stabilizer sustained skin and sub-structure damage.
A post-accident inspection revealed that the battery had little or no electrolyte in it. Battery output was 8.3 volts, with no indication of electrical current. No anomalies with the function of the alternators or regulators were observed. The airplane was equipped with a 28-volt dual-alternator electrical system. The Pilot’s Operating Handbook stated that “use of the ground service plug receptacle for starting an airplane with a ‘dead’ battery or charging a ‘dead’ battery in the airplane is not recommended.” It added that a “failure to observe this precaution could result in loss of electrical power during flight.” Landing gear extension and retraction is controlled by an electric motor, which provided hydraulic pressure to actuate the gear. Loss of electrical power prevented operation of the motor and required that the landing gear be extended manually. The pilot commented that the accident may have been prevented by inspecting the battery fluid level prior to the flight because the airplane had been tied down all winter.
Probable cause: The pilot’s decision to operate the airplane with a dead battery, his failure to properly service the battery prior to the flight and the subsequent loss of all electrical power, and his failure to verify that the landing gear was fully down and locked prior to landing all were factors.
For more information: NTSB.gov