COLORADO SPRINGS — The deadly crash of a military cargo plane fighting a South Dakota wildfire forced officials to ground seven other Air Force air tankers, removing critical firefighting aircraft from the skies during one of the busiest and most destructive wildfire seasons ever to hit the West.
The C-130 from an Air National Guard wing based in Charlotte, N.C., was carrying a crew of six and fighting a 6.5-square-mile blaze in the Black Hills of South Dakota when it crashed Sunday, killing at least one crew member and injuring others.
President Obama offered thoughts and prayers to the crew and their families. ‘‘The men and women battling these terrible fires across the West put their lives on the line every day for their fellow Americans,’’ he said in a statement.
The crash cut the number of large air tankers fighting this summer’s outbreak of wildfires by one-third.
The military put the remaining seven C-130s on an ‘‘operational hold,’’ keeping them on the ground indefinitely. That left 14 federally contracted heavy tankers in use until investigators gain a better understanding of what caused the crash.
‘‘You’ve basically lopped off eight air tankers immediately from your inventory, and that’s going to make it tougher to fight wildfires,’’ said Mike Archer, who distributes a daily newsletter of wildfire news.
‘‘And who knows how long the planes will be down?’’ he said, adding that investigators will take time to make their conclusions.
Obama signed a bill last month hastening the addition of seven large tanker planes to the nation’s run-down aerial firefighting fleet, at a cost of $24 million, but the first planes won’t be available until mid-August.
C-130 air tankers have crashed on firefighting duty before. In 2002, a civilian version of an older-model C-130 crashed in California, killing three crew members. The plane broke up in flight and an investigation blamed fatigue cracks in the wings.
The crash, in part, prompted a review of the airworthiness of large US air tankers and led ultimately to a greatly reduced fleet of large civilian tanker planes. The total number of planes in the fleet a decade ago has dwindled from 44 to nine being flown on US Forest Service exclusive-use contracts .
Another aerial firefighting plane, the Lockheed P2V, has had some problems in recent months. One crashed in Utah, killing the two pilots, and another crash-landed in Nevada.
A military spokesman said he did not know when the grounded planes would resume firefighting flights. They were used to fight fires in Colorado, Wyoming, Montana, and South Dakota.
The C-130s can be loaded with a device called the Modular Airborne Firefighting System, or MAFFS. The system can drop 3,000 gallons of water or fire retardant within seconds through a modified side door toward the rear of the plane.
The military planes had been filling up with fire retardant and flying out of Peterson Air Force Base.