What happened
On 29 April 2008, a Cessna T310Q, registration EC-DZV, was conducting a proficiency check flight at the Cuatro Vientos Aerodrome (LECU) in Madrid. The flight was intended to renew the multi-engine and instrument ratings of the pilot being tested, accompanied by an examiner.
After taking off at 08:22 UTC, the aircraft entered the airport traffic pattern. At approximately 09:02 UTC, the crew reported entering the left downwind leg for runway 2/28. Shortly thereafter, an eyewitness reported seeing the aircraft performing strange maneuvers on the downwind leg. The aircraft subsequently failed to respond to further communications from the control tower. The aircraft impacted the ground near the junction of the M-40 and R-5 motorways. Both occupants were killed in the crash, and the aircraft was destroyed.
The investigation
The CIAIAC investigation examined the aircraft's maintenance history, fuel management, and the crew's actions. Investigators found that the aircraft's Airworthiness Certificate had technically expired in November 2007 because required Supplemental Inspection Documents (SIDs) had not been performed.
Analysis of the fuel system revealed that the auxiliary fuel tanks had been selected for use, but the auxiliary pumps were only pressurizing the fuel in the lines between the main tanks and the selectors, as the selectors were not set to the main tanks. Furthermore, the left auxiliary pump showed evidence of having run dry, and the right tank transfer pump was blocked by deposits. The investigation also noted that the propellers were not feathered, and the aircraft was in a high-drag configuration with the landing gear down and flaps extended.
Findings
- The primary cause of the accident was fuel exhaustion, which led to the sequential stoppage of both engines.
- The first engine likely began to sputter during the downwind leg, but the crew likely attempted to continue the approach rather than performing an immediate emergency landing.
- The aircraft's ability to maintain flight was severely compromised by the high parasitic drag caused by a windmilling, un-feathered propeller and the deployment of landing gear and flaps.
- The crew demonstrated a lack of knowledge regarding the specific fuel system management required for the Cessna T310Q, specifically regarding the use of auxiliary tanks and pumps.
- The examiner's authorization to conduct checks had technically become void due to the expiration of his flight instructor and instrument instructor ratings.