Human factors emerge as trend in air crashes-expert

* 2009 could match 10-year high for crashes

* Developing countries strained for aviation resources

By John Crawley

WASHINGTON, June 30 (Reuters) - Human factors are emerging as a worrisome trend in global air crashes and other incidents as fatigue, complex flight systems, inconsistent training and regulation pose new challenges to airlines, a leading safety advocate said on Tuesday.

Bill Voss, president of the U.S.-based Flight Safety Foundation, a watchdog and advocacy group, told industry and government officials that 2009 could be the worst year in a decade for major commercial aviation accidents.

There have been 12 crashes this year through June and carriers globally are on pace to equal the 10-year high of 24 crashes in 1999, according to safety foundation figures.

There were 16 crashes last year.

This year's total would include a Yemeni airliner with 153 people that plunged into the Indian Ocean on Tuesday and the Air France crash in the Atlantic Ocean off Brazil on June 1 that killed 228 passengers and crew.

Both crashes involved Airbus jetliners and are under investigation.