BAGHDAD, Iraq – A helicopter crash that killed seven people yesterday is the latest in a spate of a half-dozen downings that strongly suggest that insurgents are putting more effort toward shooting down U.S. aircraft, U.S. officials say.

MARKO DROBNJAKOVIC / Associated Press
A CH-46 Sea Knight transport helicopter flew over Baghdad's heavily fortified Green Zone yesterday, the same day that militants claimed responsibility for downing a Sea Knight in an insurgent-heavy region northwest of the Iraqi capital.
|
Six U.S. helicopters have crashed or been shot down in the past 19 days – including a Marine CH-46 Sea Knight transport yesterday that took the lives of seven people.
It appears to be the largest number of helicopters lost in such a short period since the invasion.
Also yesterday, Baghdad's streets were electric with tension as U.S. officials confirmed the new operation to secure the capital was under way. U.S. armor rushed through streets, and Iraqi armored personnel carriers guarded bridges and major intersections.
The recent rash of crashes indicates insurgents have become smarter about anticipating U.S. flight patterns and finding ways to use old weapons to down helicopters. The aircraft, many of which were equipped with sophisticated anti-missile technology, still can be vulnerable to more-conventional weapons fired from the ground.
Details about the downed Sea Knight, which crashed into an open field in an insurgent-heavy region northwest of Baghdad, were still sketchy last night. Witnesses said the aircraft appeared to have been shot down, but some military officials suggested that the crash might have been caused by a mechanical failure.
U.S. officials also said there had been a previously unreported crash Jan. 31 in which a helicopter operated by a private security firm and flown in support of the State Department was forced down 10 miles south of the capital after insurgents attacked it with heavy-caliber ground fire as it flew from Hillah to Baghdad.
There have been four other fatal downings of U.S. helicopters since mid-January that have killed at least 20 people total. Military officials have suggested the crashes were caused by small-arms fire, although, in some cases, witnesses indicated missiles had been fired from the ground.
U.S. officials emphasize that a new sense of coordinated aggressiveness on the part of insurgents toward attacking aircraft, or even luck, may be playing as large a role in the high pace of crashes as improved skill and tactics among insurgent triggermen.

Associated Press
In an image made from video, smoke and flames rose from the crash of the Sea Knight yesterday.
|
A senior military official said yesterday that while the incidents were still under investigation, the recent helicopter shoot-downs appeared to be part of an insurgent strategy to inflict heavier losses on U.S. forces at the start of the new push by U.S. and Iraqi forces to secure Baghdad.
“There is certainly the expectation here that insurgents are trying to inflict some losses as we're building up forces as a means to try to discourage the Iraqis and us that this is a futile plan,” the official said.
U.S. Maj. Gen. William Caldwell said yesterday that the security plan for Baghdad “is being fully implemented as we speak,” while adding, “not all aspects are in place at this point.”
Officials have established nine new security districts in Baghdad and are creating dozens of security stations that Iraqi police and military officers will share with U.S. military personnel.
“The key difference is, this time, it's an Iraqi-led plan,” said Caldwell, the chief U.S. military spokesman in Iraq. “Not only are they planning it, they are leading.”
New coils of barbed-wire and blast barriers marked checkpoints that caused traffic bottlenecks. U.S. Apache helicopters whipped the air over parts of the capital where they hadn't been seen before.
But gunfire still rang out across the city, and some residents doubted life would get better. “Nothing will work; it's too late,” said Hashem al-Moussawi, a resident of the Sadr City Shiite enclave who was badly wounded in a bombing in December.
A U.S. official said one reason for the spate of helicopter downings is that fighters have decided to fire with greater frequency at low-flying U.S. helicopters. In past years, there has been relatively little small-arms fire against helicopters, the official said.
One Air Force commander in Baghdad said the recent crashes appear to largely be the result of old weapons that have long been available in Iraq and not an influx of new hardware or technology.
The Sea Knight, the aircraft that crashed yesterday, is a large transport helicopter, easily distinguished by its twin rotors, one mounted near the cockpit and one mounted on a tall tail. It can carry more than two dozen passengers and crew. The military said all seven people on board died in the crash but did not identify the victims.
Video of the aftermath broadcast by the BBC showed bright red flames and thick black smoke billowing from the burning hulk of the helicopter as the wreckage lay in an open field.
Witnesses said the helicopter appeared to have been attacked from the ground. “I looked at the sky and saw this big helicopter with double rotors, and it was hit in its tail and burning,” said one Iraqi who declined to give his name. He said he saw the crash while tending to his herd of grazing sheep near Karmah, an area heavy with Sunni Arab insurgents between Baghdad and Fallujah.
Another helicopter, with one rotor, was flying just behind the burning aircraft, he said. The twin-rotor helicopter flew for a half-mile more or so before crashing, he said. “I saw a lot of airplanes after the crash, and I took my herd and left,” he said. “I was afraid there would be shooting after that.”
An Internet message from an insurgent group calling itself the Islamic State of Iraq took credit for shooting down the helicopter, the latest in a string of crashes the group has claimed to have caused. The message said the group's “anti-aircraft” battalion downed the aircraft about 10:40 a.m. near Karmah, and asserted that the crash was witnessed by hundreds of onlookers shouting “God is great,” according to the SITE Institute, which tracks Internet postings by insurgent groups.
U.S. military officials emphasized that the investigation into the crash was scrutinizing a possible mechanical failure along with other potential causes.
Two U.S. officials said the previously unreported downing of the State Department helicopter last week came after it was subjected to a hail of gunfire from the ground. One official described the gunfire as heavy-caliber and said that after the helicopter crash-landed a second aircraft set down and evacuated the stranded passengers and crew.
But the official said that a quick-reaction force rushing to the crash scene was struck by at least one large roadside bomb and suffered several casualties. The force withdrew from the site, and U.S. officials decided to destroy the aircraft rather than risk it falling into insurgent hands.
Before the two most recently reported crashes, there had been at least 57 U.S. helicopters downed since May 2003, according to a tally by the Brookings Institution. The highest total for any single month was five aircraft lost in January 2004. The overall tally since 2003 showed that at least 172 U.S. troops had died in helicopter crashes, or about 5.5 percent of the total U.S. troop fatalities.
On Jan. 20, in the deadliest recent crash, attackers appear to have fired from a pickup truck near Baghdad. The first of two Black Hawk helicopters passed over the truck and saw nothing amiss. But a witness said the second helicopter fired the flares that are used to confuse heat-seeking missiles before bursting into flames and then crashing.
An Apache gunship in the area then pursued the truck and destroyed it. The U.S. military later said the debris from the truck contained tubes consistent with missile launchers.
The Associated Press and The Washington Post contributed to this report.