"Some of things he's said are not true. But some of the things they're saying against him are not true either," Krell told CNN.
Their helicopter was second in a formation of three aircraft carrying bridge parts, according to Krell. The first helicopter was hit with the RPG attack, which Williams likely did not witness from his seat in the back of the chopper.
All three of the helicopters were hit by small arms fire, however, according to Krell.
"The bridge expansions we were hauling took most of the hits," Krell told CNN.
The helicopter on which Williams was riding then dropped off the bridge parts before catching up to the other two aircraft and landing.
According to CNN, Krell was not angry with Williams over his embellishments, but acknowledged that the NBC anchor made a few errors.
"Yeah, he messed up some things and said some things he shouldn't have. I [first] heard it a few years ago," he said. "Actually one of my flight engineers said, 'Did you hear him say that? Wasn't he on our bird?'"
"After a while, with combat stories, you just go 'Whatever,'" Krell added.
But the numerous versions of the story told by Williams and others leaves it unclear just how much and how often the NBC anchor embellished on what really happened.
During his 2015 version of the story, which he told on-air Friday while honoring a member of the military who was with him during the incident, Williams said the helicopter on which he was flying was hit by an RPG, but he did not specify whether any other aircraft were hit.
His most recent tale sparked backlash among crew members who were flying on separate aircraft in Williams' fleet. Crew members told Stars and Stripes that the chopper Williams was riding on did not take fire, and that he was not near the other helicopters during the attack.
Krell's version of events, as told to CNN, may explain why some crew members thought Williams was nowhere near the attack, even if he was in fact right behind the aircraft hit with RPG fire.
In a 2007 blog post, Williams said that the RPG fire hit a helicopter in front of him.
"Not long after Wayne's warning, some men on the ground fired an RPG through the tail rotor of the chopper flying in front of ours. There was small arms fire. A chopper pilot took a bullet through the earlobe," Williams wrote.
He mentioned dropping off the bridge parts, but did not mention any gap in time between the different helicopters.
"All four choppers dropped their heavy loads and landed quickly and hard on the desert floor," he wrote.
And during an 2013 appearance on "Late Show with David Letterman" Williams said that "two of our four helicopters were hit by ground fire, including the one I was in — RPG and AK-47."