Wing spar metal fatigue may have been a major factor in the fatal crash of a Chalks Ocean Airways Grumman G-73T Turbo Mallard close to Miami Beach, Florida in December.


All 20 people on board the 1947-built twin-turboprop amphibian were killed when it appeared to suffer structural failure of its right wing and plunged into the sea streaming fire.

After initial wreckage examination, Mark Rosenker, acting chairman of the US National Transportation Safety Board, said: “This crack appears to extend through a majority of the [right wing] spar at the location of the separation [the wing root].” It is not yet clear whether the separation was precipitated by another event, such as an engine or propeller problem or turbulence, or if it failed spontaneously.

The aircraft had just taken off from the Miami seaplane base on a 19 December scheduled flight to Bimini in the Bahama islands, about 80km (45nm) south of Miami, with two crew and 18 passengers on board.

Fort Lauderdale, Florida-based Chalks Ocean Airways, which operates a fleet of five Mallards that connect Miami’s Watson Island seaplane base with Bimini and Nassau in the Bahamas, is one of the world’s oldest airlines, having been founded in 1919.

Source: Flight International