Federal investigators trying to determine the cause of the fatal crash of a Seattle news helicopter said Thursday they will be examining the pilot’s recent history for factors that could contribute to fatigue.

The Seattle Times writes that Dennis Hogenson, acting deputy chief of the National Transportation Safety Board (NTSB) Western Pacific Region, said in an interview that officials want to understand how pilot Gary Pfitzner, who died in the Tuesday crash, balanced his two jobs — early mornings in the helicopter followed by work as a technical analyst at Boeing. Officials are collecting information on Pfitzner’s activities in the hours and days before the crash that occurred upon takeoff from KOMO’s helipad.

“That’s going to be a big part of the investigation,” Hogenson said.

Examination of a pilot’s rest periods before a crash are a standard part of any such inquiry — one part of an investigation, Hogenson said, that includes a review of the helicopter’s components, maintenance records and the weather conditions at the time of the crash.

Some witnesses have said the helicopter made an odd sound as it tried to lift off its pad before losing control and tumbling to the street.

Hogenson said two NTSB investigators will review what Pfitzner was doing in the 72 hours before the crash, and they may extend that analysis to a full week before the accident. Some of the work will involve reviewing phone records and talking with people close to Pfitzner, but Hogenson said the NTSB wants to give family members some time to grieve before that detailed discussion takes place.

Officials have described Pfitzner, 59, as experienced, with some 7,700 hours of flying time. Pfitzner died in the crash along with photojournalist Bill Strothman.

Richard Newman, burned when the helicopter struck his car, remains in serious condition in the Harborview Medical Center intensive-care unit.

While there are rules governing the amount of rest commercial-airline pilots must receive before flying — including an opportunity for eight hours of uninterrupted sleep — Hogenson said the rules are less stringent for private helicopter pilots.

Mark Pfitzner said earlier this week that his brother typically had a seven-hour sleep window, going to bed at 8:30 p.m. and getting up at 3:30 a.m. He said in a subsequent interview that his brother never worked fatigued and did not operate unsafely.

Boeing declined to describe Pfitzner’s recent or typical hours, and KOMO-TV declined to comment on his recent schedule. Officials with helicopter operator Helicopters Inc. did not return a call seeking comment.