For a year or more, the severity of this accident puzzled me, and how an emergency landing that "had the runway made" turned into a fatal tragedy was not adequately addressed in the NTSB Reports. Although the airplane sustained minor damage when it struck the runway approach lights, that would have been the extent of the incident IF THE THROTTLES HAD BEEN CLOSED. When the aircraft struck the approach lights, engines Nos. 1 & 2 (left side) were operating at or near full throttle, and for some reason, nowhere addressed in the NTSB Reports, the throttles were not closed. Engine No. 4 was already feathered and Engine No.3 was ailing and not providing anything near full or even partial power.
With Engines Nos. 1 & 2 operating at high power settings, the aircraft veered sharply right and ultimately collided with a de-icing fluid (glycol) tank located on the airport property. These two engines were found to have been operating at or near full throttle when the aircraft impacted the glycol tank. The subsequent fire completed the destruction of the airplane and resulted in the deaths of those not killed at impact.
For the above reasons, this accident would just not let loose of my mind; consequently, I gave it much thought and studied all of the information available from the NTSB documents (I even read the entire Accident Docket several times). I also spoke at length with a good friend of mine (a retired FAA guy) who knew personally the B-17 pilot and was familiar with the Collings Foundation aviation operations.
Several of the posters to this thread have touched upon the possibility that the pilots' failure to wear the available shoulder harnesses could have been a factor in the failure to close the throttles, and it was pointed out that the violent swerve to the right could have pinned Mac (the PIC) against the left side of the cockpit, making reaching the throttles difficult for him ... if not impossible. Thinking about this, I realized that the co-pilot's body would have also been flung to the left during the crash sequence, quite possibly impacting the throttles, pushing all four full forward. It should be noted that the co-pilot's injuries were different than those of the PIC, in that he suffered considerable injury to his thorax, which (according to the Medical Examiner) was the cause of his death (not fire/smoke inhalation). During all of this, No.4 was caged, and No.3 was developing only minimal power at best; consequently, all of the available thrust was on the left, causing the airplane's continued swerve to the right.
After eating at me for a few weeks, I decided to call the NTSB with my theory about the movement of the co-pilot's body. I eventually was able to speak (telephone) with the Investigator In Charge (IIC), Robert Gretz and shared the theory with him. He said that he and his colleagues at the NTSB had also been puzzled as to why the throttles were not closed during the accident sequence. He said he'd take another look at the evidence and see if anything else revealed itself concerning the question of the throttles. He called back a few weeks later and said that the theory still "held water" and that something else from the wreckage seemed to support my theory. Although not included in any of the published NTSB documents concerning this accident, the No.2 throttle lever had been found bent severely to the LEFT.
Anyway, that's my theory, and the NTSB thinks that it's reasonable and that the wearing of shoulder harnesses could have reduced this accident to the level of merely a reportable incident. I don't know if any new recommendations/regulations will result from all of this; however, all we can do is wait and see. I understand that these Living History flight operations operate under a waiver, and many FAA Regulations are "relaxed" for these operations; however I assume that these operations are now "under the microscope" and changes may be coming.