Houlton Intl Airport
Aircraft Accident/Incident Report

Houlton, Maine 04730
Friday, January 17, 2014 20:40 EST

On January 17, 2014, about 2040 eastern standard time, a Eurocopter AS350B3, N578AE, operated by U.S. Customs and Border Protection (CBP), was substantially damaged following an engine anomaly at Houlton International Airport (HUL), Houlton, Maine. The two commercial pilots were not injured. Night visual meteorological conditions prevailed. The helicopter was operating on a company flight plan for the local public use flight. According to the copilot, the helicopter had just returned to HUL after a search and rescue mission, with the copilot flying. The crew then commenced takeoff and landing practice for night flight and night vision goggle recurrency. The copilot stated that he had completed three landings to runway 23, with one landing at the beginning, one near the middle, and one toward the end. He then took off again, hovered, and began a transition to forward flight with forward cyclic and a slight amount of increased collective. As he was beginning to apply cyclic, he heard and felt a loud explosion from the rear of the helicopter, followed by a severe vertical vibration, and the engine noise became very loud. The helicopter began to experience cyclic controllability problems along with some yaw instability as well. The pilot in command (PIC) called out the rotor rpm warning horn, but the copilot was unsure whether it was constant or intermittent due to the engine noise. Helicopter control continued to rapidly decay for the next 5 to 10 seconds, at which time the PIC took control. The copilot subsequently made two mayday calls over the radio, and almost immediately, the helicopter began "severe" pitch and roll oscillations. During some of the oscillations, the left side door came open, but the copilot was able to get it closed again. About that time, he also noticed the red GOV light was illuminated. After 10 to 20 seconds, the PIC was able to regain some control of the helicopter, there was a decrease in engine and rotor noise, and the PIC was able to land the helicopter beyond snow banks at the end of the runway. After performing an emergency shutdown, the PIC said he thought the helicopter was on fire, and although the FIRE light was not illuminated, there was an orange glow reflected in the snow. Upon exiting the helicopter, the copilot saw flames coming from the engine compartment; he tried to extinguish the fire with a portable fire extinguisher, but without effect. The local fire company arrived about 10 minutes later and subsequently extinguished the flames. According to the PIC, after the explosion, the Nr overspeed warning sounded and a vertical vibration developed. At that point, the helicopter had not yet begun yaw oscillations, so the PIC felt they still had tail rotor thrust. He could not quite hear if the Nr warning was intermittent or continuous (low Nr) and told the copilot they could have low rotor rpm. He believed that the copilot then lowered the collective slightly in response to his statement, but the noise increased and the oscillation began. The PIC then took control of the helicopter. As he did, he observed two amber caution lights and what he believed were two red warning lights. Severe vertical vibrations and almost uncontrollable yaw oscillations continued, as did a high Nr warning. The PIC then focused on trying to keep the helicopter's skids level, not hitting the ground, and not flying out of ground effect. He could not ascertain airspeed, and there were three instances when he estimated that the helicopter entered 30- to 40-degree banks. Throughout the event, the PIC could not adjust collective without inducing "extreme" attitude excursions. He could also not maintain the helicopter in a position where he could roll off the throttle. Then, after about 30 seconds, the attitude excursions began to "calm down," and the pilot was able to land the helicopter beyond the snow bank. As the helicopter touched down, the PIC noted that the red FIRE light was not illuminated, and that the original two red lights he saw were actually an amber ENG CHIP light and the red GOV light. After the event, and reviewing training materials, the PIC was able to estimate that the amber lights he saw were the FUEL P and DOOR lights. Federal Aviation Administration and NTSB personnel did not respond to the scene, while CBP investigators did, along with investigators from Airbus Helicopters (formerly American Eurocopter) and Turbomeca, who were serving as advisors to the state of manufacturer and design, France. The Arriel 2B engine and some additional components were removed from the helicopter and shipped to Turbomeca, where additional examinations occurred with NTSB oversight. Results are pending.

Not Yet Reported