Incident Description
An investigation examined an incident involving a twin-engine airplane en route to its home airport. During the flight, the airplane either experienced a loss of power to the right engine, or the pilot decided to shut that engine down. Although the home airport had night visual meteorological conditions, and no evidence of any malfunction with the remaining left engine was found, the pilot chose to fly a night precision instrument approach to an airport 45 nautical miles closer. That airport had a reported visibility of 1 mile and a ceiling of 100 feet. Additionally, fog was present at the airport, unknown to the pilot.
Sequence of Events
The pilot did not advise or seek assistance from air traffic control or the company regarding the engine issue or the diversion. As the airplane broke out of the clouds, it was not in a stable condition. While approaching the runway with full flaps deployed—exceeding the 25 percent maximum recommended for a go-around—the pilot added full power to the left engine. The combination of high power setting, slow airspeed, and full flaps resulted in a minimum control speed (Vmc) roll.
Investigation Findings
Investigators could not determine why the right engine was inoperative. No mechanical or fuel-related anomalies were found that would have precluded normal operation of that engine. The airplane was equipped with two engines, and the remaining left engine showed no signs of malfunction.