The National Transportation Safety Board released hundreds of pages about the August 2008 helicopter crash that killed several local wildland firefighters.

The National Transportation Safety Board released hundreds of pages about the August 2008 helicopter crash that killed several local wildland firefighters.

However, in all that paper, the NTSB doesn't make any conclusions about the cause of the crash, only gives facts about it and similar crashes and interviews with eyewitnesses. "Clutch slip," a malfunction in transferring power from the engine to the rotors, appears to remain the leading suspect as to the cause of the accident, known as the "Iron 44 incident," on the fire lines in northern California.

Other factors discussed include possible overloading and contamination that has blocked an engine fuel control valve in the same make of engine, resulting in other crashes.

Nine of 13 people aboard the Sikorsky S-61, which was owned by Carson Helicopters of Merlin, were killed, including seven firefighters for Merlin-based Grayback Forestry. Co-pilot William Coultas of Cave Junction survived, but was seriously injured. The helicopter was lifting off from a mountaintop in rugged terrain to ferry out firefighters when it fell back to earth, crashed and burned. Witnesses said it lost power.

"Clutch slip" has been mentioned as a possible cause since three weeks after the Aug. 5, 2008, crash. That's because the Iron 44 crash resembles four others that killed or seriously injured West Coast logging pilots flying Sikorsky S-61s. Safety officials determined "clutch slip" was the cause of the other four. In all five cases, the helicopters crashed while lifting off.

As for possible overloading, the NTSB's estimate for the weight of the aircraft at the time of the crash was 19,008 pounds, including people, fuel and equipment. That would have been 2,000 pounds higher than the U.S. Forest Service recommends, according to The Oregonian newspaper, which analyzed the latest report. Carson Helicopters maintains that estimate is several hundred pounds too high, though.

Determining the cause, unfortunately, won't bring those brave firefighters back to life. The families will still have to suffer with the pain of losing a loved one.

What makes pinpointing the cause so important is doing so will allow the problem to be fixed, whether it's a mechanical defect or misuse of the aircraft, such as overloading. That could prevent similar crashes and deaths. Also, determining a cause will help settle many millions of dollars in lawsuits that have been filed in this case — by families, insurance companies and others — against Carson Helicopters, Sikorsky and others. The Oregonian reports that at least four actions against Sikorsky and parts manufacturers have already been settled out of court.

One would hope that the NTSB could wrap up its investigation soon, so cases can be settled and problems fixed as soon as possible. Unfortunately, based on its progress to date, it looks like its investigation into Iron 44 will grind on for many more months, if not years.