How Kentucky UPS plane crash unfolded and what could have caused it

Old_Joe

Following are edited excerpts from a current BBC report:

The National Transportation Safety Board (NTSB) - which is investigating the crash - said they have recovered airport CCTV footage that shows the plane's left engine falling off from the wing during takeoff. The agency has also recovered the cockpit flight recorder and the flight data recorder, known as the black box, from the wreckage. The 38,000 gallons of fuel on board the MD-11 jet needed for the flight escalated the blaze, which quickly spread to several buildings beyond the runway and burned for hours.

Data from tracking website FlightRadar24 shows the plane began to taxi along the 17R runway at around 17:15 local time and managed to reach a top speed of 214mph. But verified footage shows that by the time the plane reached this speed a fire had completely engulfed its left wing and the aircraft struggled to climb away from the runway before the explosion.

The NTSB said the plane's engine was on fire as it was working to take off and then detached from the wing. The plane was able to climb to 175 ft and cleared a fence at the end of the runway before veering into buildings and businesses surrounding the airport. Analysts suggested that a dramatic failure of two of the engines may have been responsible for the disaster. The MD-11 transport plane uses three engines. Two are mounted under the wings, and a third is built into the tail at the base of the vertical stabilizer.

A senior lecturer in aviation operations said the footage appeared to show the third engine had been damaged because it expelled a burst of smoke. The damage could have happened while it was pelted with debris from the fire and the engine detaching: "The upper engine that expelled a puff of smoke appears to wind down almost immediately afterwards," he said. "That left only the right engine producing thrust, creating a severe power imbalance and leaving the aircraft unable to gain height. "Losing two engines during take-off leaves the aircraft with only a third of its power and little chance of maintaining flight, especially at maximum take-off weight.

Footage confirmed by BBC Verify showed a blaze engulfing the left wing of the plane, which then tilted to the left as it attempted to gain lift and take-off. Two experts independently suggested the left engine may have detached from the plane after suffering from a mechanical or structural failure. And the NTSB later confirmed that the left engine detached from the plane's wing during takeoff. A retired airline pilot and aviation safety expert told BBC Verify that it was "almost unheard of" for an engine to detach in flight. He also said the cargo plane would have been able to fly with just two engines but the damage caused by the fire on the left wing was likely so great it caused the plane's engine built into the tail to lose thrust.

Additional information: A report in The Guardian states that Flightradar24 said the plane had flown from Louisville to Baltimore earlier on Tuesday before returning to Louisville. That would seem to suggest that no significant maintenance work occurred immediately before the flight departure for Honolulu. That in turn suggests the possibility of an engine turbine blade failure, where the failed blade rips through the immediate area and causes additional damage to the engine and the surrounding area. Possibly that in turn caused damage debris to be sucked into the rear engine, completing the death sentence.

Additionally, the Wall Street Journal is reporting that the UPS cargo plane that crashed Tuesday was 34 years old and needed a critical repair on its fuel tank in September. The MD-11 plane was grounded in San Antonio from Sept. 3 through at least Oct. 18, according to flight records. Maintenance records with the Federal Aviation Administration show the jet needed a permanent repair to fix a crack in the fuel tank before it returned to service.

I have no idea if this would have any significance in this disaster, but if it turns out that the fuel tank repair was on the left wing, some serious questions will be asked.


Comment: This excellent BBC report is by far the most detailed explanation of the actual mechanical failure sequence that I've come across so far.

Mark

Thanks OJ. Just sad especially for those who lost their lives just doing their jobs.