The National Transportation Safety Board sent an accident investigator to Iowa within hours of a fatal plane crash this week. Investigator Jim Silliman says other agencies are also working on gathering details of the Cherokee Six crash that killed four people. The FAA’s gathering background information the pilot, the aircraft, whether an air-traffic control tower was talking with the pilot or watching his flight on radar. He says rather than assign fault, his job is to collect as much information as possible to reconstruct what happened and what might have caused it. He says they’ll look for where it hit, whether all parts are at the crash site or some may have come off in the air, how far it traveled across the ground, and then look at the condition things were in like the controls, surfaces, cables, engine and propeller. In addition to the FAA and NTSB, engineers from Piper, the airplane maker, and Lycoming, the maker of the engine, arrived to look over the wreckage and search for clues. One thing they don’t have is a message, as the pilot was not in radio contact with a control tower when the plane went down in a field halfway between Iowa City and Newton.There’s been no report of any “mayday” or distress call. Larry Lawson, Altoona firefighter, died in the crash along with his daughter, Lisa Lawson, who’d recently returned from teaching in Spain. The other victims were a Spanish man who’d accompanied her to Iowa, and Larry’s brother Dan Lawson, the pilot of the plane.