Improper maintenance blamed in 2011 helicopter crash near Las Vegas

WASHINGTON Jan 29 (Reuters) - The U.S. National Transportation Safety Board said on Tuesday improper maintenance was the likely cause of a Dec. 7, 2011 air tour helicopter crash near Las Vegas that killed the pilot and four passengers.

The board said its investigation of the crash of a Sundance Helicopters Eurocopter AS350 found inadequate maintenance, including degraded material, improper installation and inadequate inspections.

"This investigation is a potent reminder that what happens in the maintenance hangar is just as important for safety as what happens in the air," NTSB Chairman Deborah Hersman said in a statement.