A 44-year-old woman was airlifted to Maui Memorial Medical Center yesterday with serious head injuries after crashing during a downhill bicycle tour of Haleakala.

The accident happened at 7:15 a.m. when the bike rider apparently failed to negotiate a turn at the 8,500-foot level of Crater Road within the national park and slammed into some rocks, said park spokesman Dominic Cardea.

Leaders of the commercial bike tour summoned help, and an ambulance took the injured woman to Hosmer Grove, where she was picked up by a helicopter and flown to the Wailuku hospital. An update of her condition was not available.