Bill Coultas still struggles to make sense of what happened.
Coultas was the co-pilot on a Carson Helicopters Sikorsky S-61N that crashed Aug. 5, 2008, while on a firefighting mission in California’s Shasta-Trinity National Forest. Nine of the 13 aboard were killed, including PIC Roark Schwanenberg and U.S. Forest Service (USFS) check pilot Jim Ramage. During its third takeoff that day from Iron 44, a 6,000-foot-msl helispot, witnesses on the ground said the helicopter labored to gain altitude before sinking and clipping trees. At 7:41 p.m. the helicopter came to rest on its side and was immediately engulfed in flames. The wreckage burned until the next morning. Coultas survived with severe burns and other injuries.
Late last year, the NTSB found that the crash’s probable cause was Carson’s intentional understatement of the helicopter’s empty weight; alteration of the power-available chart to exaggerate the helicopter’s lift capability; the practice of using unapproved, above-minimum-specification torque in performance calculations that, collectively, resulted in the pilots’ relying on performance calculations that significantly overestimated the helicopter’s load-carrying capacity and that did not provide an adequate performance margin for a successful takeoff; and insufficient oversight by the USFS and the FAA. The NTSB also noted contributory factors that included the 1965 helicopter’s lack of crash-resistant fuel tanks and outdated seats.
Carson continues to question the role played in the accident by a contaminated fuel control unit (FCU) on the aircraft’s number two GE CT58-140-1 engine. The NTSB dismissed the FCU as a cause of the crash. However, shortly after Coultas was hospitalized, he said he had seen a torque split on the gauges for the number-two engine and engaged the emergency throttle for that engine in the moments before impact. Post-crash investigation found that throttle half-way engaged. Coultas confirmed this statement last December. He also disputed the NTSB’s temperature data as well as Sikorsky’s acoustic modeling of the cockpit voice recorder, which concluded that he and the PIC flew the S-61 to engine topping before the crash.
Landing conditions at the helispot the day of the crash were very dusty, so dusty that Coultas and Schwanenberg had called in a water drop in the hope of improving conditions. Coultas said the brownout conditions at H-44 were so bad that they had to reposition. But the drop missed. Less than an hour before the crash, during a fuel stop at Trinity Helibase, a mechanic noted that both engine intakes were covered in ash, but the first stage stator was clean. He also began wiping off a thick ash layer that had made a film on the leading edge of the main rotor blades. Thirty-one minutes later, the helicopter was back on the ground at H-44, picking up the first of the last three loads of firefighters for transport down the mountain before dark.
Coultas noted that the temperature had dropped 12 to 13C since their performance calculations were first made and that the load on this trip was actually 200 pounds less. At 7:40:42, Schwanenberg began increasing the collective for takeoff. Coultas called out the power as torque increased to 75, 80, 85, 90 and then 103. Nine seconds later he called it back down to 100. He stayed focused on the instrument panel so, in the event of inadvertent IMC, he could take the controls and perform an instrument takeoff. “I am calling out power and we transition to forward flight, accelerating to about 15 knots.”
As the helicopter moved forward, Coultas shifted his focus outside the helicopter’s right cockpit window, on guard for any drift close to nearby trees on the right and the group of firefighters standing below them. “We are climbing, starting to gain speed and everything is going fine.”
Then suddenly the nose plunged 15 degrees. Schwanenberg pulled it back up. Coultas moved his left hand to the throttle quadrant, then moved his gaze inside the cockpit and reestablished on the instrument panel. He heard the rotor rpms slowing down. He looked at the gauges and started making call outs. The rpms were drooping. He saw the torque split on the engine gauges. Number Two engine was producing less power. Schwanenberg was looking down out his left-side bubble window at the approaching ground and cursing. Coultas started pushing the Number Two emergency throttle forward. But it was too late. The helicopter pitched up and down and yawed left and right. The pitch motions became more pronounced. “Everything starts to get violent,” Coultas recalled.
He heard the whack of the helicopter hitting a tree and then another. The blades kicked up so much dirt that the last thing Coultas saw before impact—the windscreen—was completely brown. And then it went black.
As Coultas came to outside of the helicopter, he noticed that his helmet and gloves were burning. He staggered to get up and get away from the flaming wreckage. “I’m on fire.”
The burns were so severe that parts of his bones were visible at the time.
Coultas continues to recover from his injuries and there is much about the crash and the investigation he still does not understand. He disagrees with some of the NTSB’s methodologies and conclusions. Many of his questions to the Board have not been answered to his satisfaction and may never be. He says power fluctuations on the S-61 are not new phenomena, there are years’ old memos on it in the NTSB’s public docket concerning this crash. He wonders why it took so long for civil operators to get FAA approval to use the finer 10 micron fuel filters as opposed to the old 40 micron filters, only after his crash, when the military had been using them on their S-61s for years.
Much of the civil litigation surrounding the crash has been resolved, but Coultas and his attorneys are still fighting. In the wake of the NTSB’s public hearing last year, several ongoing criminal investigations into the crash also were revealed. Bill Coultas is hoping that these proceedings give him the answers the NTSB could not.