Crashed Seaplane Had a Cracked Wing Beam

Chalk’s Ocean Airways grounded its fleet Wednesday after investigators discovered a crack in the main support beam of the wing that fell off Flight 101, which crashed Monday off Miami Beach, killing all 20 people on board.

The 58-year-old Grumman G-73 Turbine Mallard seaplane lost its right wing and plunged into the water after taking off for Bimini. On Wednesday, salvage workers found the plane’s voice recorder, which was sent to Washington for analysis. The recorder was unreadable, said Mark V. Rosenker, acting chairman of the National Transportation Safety Board.

Investigators found a fatigue fracture on the wing’s aft lower spar cap, which connects the wing to the fuselage, Rosenker said, adding that such damage would not have been found in a routine check. “This is not a walk-around type of inspection,” he said. “You’re going to have to do a significantly more sophisticated type of inspection.”

The fleet’s four remaining planes are the same model as the one that crashed.

Despite the discovery of the wing crack, it was unclear what caused the wing to fall off. Witnesses reported a fire or explosion, and a video of the crash showed flaming wreckage falling into the water. Aviation safety experts said it was possible that an engine or fuel-line malfunction caused an explosion that knocked the wing off.

“Sometimes these things happen because of a whole combination of events that aren’t really related,” said Grant Brophy, air safety investigator and director of flight safety and security at Embry-Riddle Aeronautical University in Daytona Beach, Fla.

The plane’s crew was identified Wednesday as pilot Michele Marks, 37, of Boynton Beach, Fla., and co-pilot Paul DeSanctis, 34, of Reading, Pa.

Mark Marks, the pilot’s husband, was overcome with grief at the couple’s Boynton Beach home. He said his wife flew to Bimini nearly every day, and he often accompanied her.

“The bottom’s been pulled out from under me,” he said. “She’s my wife of eight years. I’m destroyed.”

Chalk’s, which flies from Fort Lauderdale, Fla., and Miami to the Bahamas, canceled all flights to allow its planes to be inspected, said general manager Roger Nair. He said Chalk’s hoped to resume its schedule within a week.

“These are trying times for this great airline,” Nair said. “We will get through this difficult time so we’ll be back in the air soon.”

Federal investigators plan to review Chalk’s maintenance records and manuals.

“This crack appears to extend through a majority of the spar at the location of the separation,” Rosenker said. “I suspect had they known that there was a deep or a serious fatigue crack -- and they would have learned that, perhaps, through a series of inspections -- they would have repaired it and we wouldn’t be here today.”

Federal Aviation Administration records show corrosion had been found on the plane’s right wing -- the one that fell off -- and on the top aft beam during a 1991 inspection. The records do not indicate what was done to address the problem.