PRELIMINARY REPORTS
Cargo Flight Crashes on Landing in West Virginia
Short SD3-30, May 5, 2017, Charleston, W.Va.—An early-morning arrival at Charleston Yeager International Airport (CRW), Charleston, W.Va., ended badly for Air Cargo Carriers Flight 1260, a Short SD3-30, when it crashed on approach to Runway 5, killing both pilots and destroying the airplane. The Part 135 cargo flight was arriving from Louisville International Airport (SDF), Louisville, Ky., in IFR conditions. The NTSB is investigating the cause of the accident.
MU-2 Loses Cabin Window in Flight
Mitsubishi MU-2, May 18, 2017, Little Rock, Ark.—An MU-2 pilot on a Part 91 flight sustained minor injuries after one of the twin turboprop's cabin windows blew out at altitude near Little Rock, Ark. The pilot initiated an emergency descent to a successful landing in Little Rock.
AS350B2 Hits Terrain in Fog Near Herbert Glacier
Airbus AS350B2, May 22, 2017, Juneau, Alaska—A commercial pilot flying seven passengers on a Part 135 on-demand sightseeing flight to glaciers above Juneau, Alaska, in an Airbus AS350B2 struck remote mountainous snow-covered terrain 21 miles northwest of Juneau. The pilot and three passengers sustained minor injuries in the accident and the helicopter was substantially damaged.
VFR conditions were degrading rapidly in what the pilot termed “flat light” on the Herbert Glacier at the time of the accident, and company flight-following procedures were in effect.
During an interview with the NTSB investigator, the pilot reported that she departed from the Juneau International Airport to pick up cruise ship passengers from a remote dog sledding camp on the Herbert Glacier. She landed at the camp, picked up six passengers and headed back. Three-quarters of a mile from the camp, while descending over an area of featureless, snow-covered ice, the pilot reported that she was maintaining visual reference with a rock wall on the right side of the helicopter. As the flight progressed downslope, she saw an area ahead that was “fogged in" and she chose to turn back to the dog sledding camp. While slowly turning 180 degrees to the right, the helicopter hit the ice and came to rest inverted.
All the occupants exited the helicopter, and the pilot used a handheld radio to request emergency assistance. The personnel at the dog sledding camp contacted the operator's headquarters in Juneau, which sent another company helicopter to extract the pilot and passengers from the accident site.
According to the pilot, in addition to fog, flat light conditions were present at the time of the accident. The helicopter sustained substantial damage to the fuselage, the main rotor system, the tailboom and the tail rotor system. The wreckage was recovered and transported to a secure facility.
Let L-410UVP Destroyed on Landing
Let L-410UVP-E20, May 27, 2017, Nepal—A Let L-410UVP-E20 turboprop twin operated by Summit Air was destroyed in an accident when it attempted to land on Runway 6 at Lukla-Tenzing-Hillary Airport in Nepal, killing both the captain and copilot. The aircraft was operating a cargo flight from Katmandu with a crew of three. An airport CCTV recording shows the aircraft descending through the clouds, then climbing, possibly in an attempt to go around. The aircraft then lost altitude in a nose-up attitude and hit the ground in steep, rocky, wooded terrain, nine feet below the runway threshold level.
King Air E90 Night Flight Ends Seconds After Takeoff
Beech King Air E90, June 13, 2017, Ruidoso, New Mexico—A Beech King Air E90 with just the pilot and one passenger aboard lifted off on a night flight from Sierra Blanca Regional Airport in Ruidoso, N.M. and traveled less than half a mile from the departure end of the runway before hitting the ground and being consumed by fire, killing both occupants.
An IFR flight plan was filed for the flight, which was heading to Abilene Regional Airport, Abilene, Texas. The airplane wreckage path was distributed along a heading of 138 degrees and was 168 feet long. Both propellers were separated from the engines and were resting along the debris path. Both propellers exhibited S-shaped bending, leading-edge damage and chord-wise scratching consistent with engine power at the time they struck the ground. The NTSB is continuing to investigate the cause of the accident.
South African MD500E Down in Bulfontein
MD Helicopters MD500E, June 14, 2017, Bulfontein, South Africa—No one was injured when an MD500E with South African registration was substantially damaged in a forced landing near Bulfontein, South Africa. The pilot and two passengers were on a private flight when the pilot made the emergency landing. The South African Civil Aviation Authority Accident and Incident Investigations Division is investigating, and engaged the NTSB since the helicopter’s engine and design are of U.S. origin.
FINAL
NetJets Embraer Phenom 300 Overran Runway
Embraer Phenom 300, April 19, 2014, Conroe, Texas—The NTSB determined that the copilot’s application of the emergency parking brake (EPB) during landing on a wet runway caused the aircraft’s braking system to lock up, resulting in a runway overrun of the NetJets Embraer Phenom 300 on a Part 91 relocation flight from Nashville, Tenn., to Lonestar Executive Airport (KCXO) in Conroe, Texas. The aircraft came to rest in a ditch past the end of the runway, sustaining substantial damage. No one was injured.
The cockpit voice recorder (CVR) proved that the pilots received the automatic terminal information service (ATIS) information and calculated the runway length required for a wet runway landing. They then chose to land on Runway 1, the longer runway. The pilot-in-command (PIC) told investigators that the flight encountered light rain during the approach but that the rain was moving away from the airport and that this alleviated any concern about standing water on the runway. He added that both he and the copilot had previously landed the Phenom 300 in moderate-to-heavy rain with no decrease in braking ability.
The CVR recorded the pilots briefing for the approach and missed approach procedures. Subsequently, the tower controller cleared the Runway 1 Rnav approach, and the pilots then discussed alternate airports in the area. The tower controller cleared the airplane to land and stated that moderate-to-heavy rain was at the airport. The pilots conducted the before-landing checklist and continued the approach. The copilot was flying. They saw the runway at 600 feet agl, and the copilot disengaged the autopilot at 400 feet. At 200 feet, the copilot reduced the power and adjusted the attitude and airspeed for a stabilized approach with a maximum airspeed of 130 knots.
According to the air traffic controller who witnessed the accident, the airplane touched down just past the 1,000-foot marker on the runway and did not appear to decelerate as it continued down the runway.
In his post-accident written statement, the captain noted that the landing appeared “smooth." The copilot stated that he began braking with half pressure and continued to increase the brake pressure to maximum, a normal braking procedure for the Phenom 300.
Sounds on the CVR consistent with the airplane touching down were followed by the pilots exclaiming that the airplane was not slowing down. The copilot said, “Brakes. Emergency brakes,” followed by “Nothin' man" and “I got nothin'."
The captain exclaimed, "Where's the brakes? Don’t go sideways, don't go sideways." The airplane exited the departure end of the runway and continued about 400 feet through soft/muddy terrain before coming to rest halfway down a ditch. The distance between the ground tracks made by the nose tire and the right main gear track was 18 inches, indicating that the airplane skidded after it departed the runway surface. A flat worn spot was visible on both the left and right main tires. Both tires showed evidence of reverted rubber hydroplaning.
The NTSB performed a detailed analysis of both runway conditions at the time of the accident and aircraft performance factors, determining that per the aircraft’s performance tables, there was both adequate distance for stopping and adequate traction. An examination of the brake system and the data downloaded from the brake control unit (BCU) indicate that the brake system functioned as commanded during the landing.
The performance study determined that if the EPB had not been set and the braking friction had continued at levels attained early in the landing roll, then the airplane would have come to a stop with 331 feet of runway remaining. This turned out to be considerably less than stated in the performance section of the Phenom 300 Pilot's Operating Handbook. The study concluded that the braking friction deficit observed in this and other accidents examined during the course of this investigation showed that the airplanes' stopping performance was more consistent with airplane flight manual landing distances for runways contaminated with standing water than for runways that were merely “wet."
The NTSB stated, “The root cause of the wet runway stopping performance shortfall is not fully understood at this time; however, contributors are runway conditions such as texture (polished or rubber-contaminated surfaces), drainage, puddling in wheel tracks and active precipitation. Analysis of this data indicates that 30 to 40 percent of additional stopping distance may be required in certain cases where the runway is very wet, but not flooded.”
As a result of this accident NetJets has issued three Flight Operations Bulletins addressing braking on wet runways, and added a section to its Aircraft Operations manual. Embraer has also issued (and revised several times) a Flight Operations Letter addressing braking on wet runways for the aircraft type, noting, “The emergency parking brake will always deliver worse performance when compared to the normal brakes with anti-skid protection.”
Mexican Caravan Crashed After Engine Repair Work
Cessna Caravan 208B, April 1, 2016, Durango, Mexico—The Dirección de Investigación de Accidentes, a part of the Dirección General de Aeronáutica Civil (DGAC), determined that the probable cause of the 2016 crash of a Cessna Caravan 208B that killed three people, including the pilot, and seriously injured six others was the loss of engine power from a fatigue fracture of a compressor turbine (CT) disc blade. The engine had undergone compressor turbine vane ring reworking without authorization from the manufacturer, and those parts were installed in the overhauled engine.
The pilot was flying from Tayoltita Airstrip to Durango-Guadalupe Victoria airport (DGO), Mexico, with nine passengers when the aircraft lost engine power 15 minutes into the flight while climbing through 9,500 feet. The pilot got off an emergency call before deciding to land in a riverbed in a canyon, and during the landing the left wing hit a tree, swinging the fuselage, which subsequently hit several large boulders embedded in the riverbed, causing the aircraft to split into two sections. A search-and-rescue mission launched within five minutes of receipt of the emergency radio transmission, which aided in the survival of six of the passengers.
The DGAC determined that the aircraft’s PT6A-114A was overhauled on May 21, 2015, after more than 3,000 cycles. All 100-hour inspections subsequent to the accident were nominal. The engine was extracted from the wreckage and sent to Pratt & Whitney Canada, which found that the turbine compressor vane ring processed and installed in the overhaul (part number STI8) was released for service by Southwest Turbines. The FAA-approved repair consists of replacing the entire CT vane ring core, leaving only a portion of the inner cover bracket. Pratt & Whitney Canada does not approve of the Southwest Turbines repair, and determined that it was the cause of the engine power loss that subsequently caused this accident.
Pratt & Whitney Canada conducted a number of tests on repairs similar to those performed by Southwest Turbines at the CT vane ring and noted a significant increase in vibratory stresses in CT blades caused by dimensional deviations of the CT vane in comparison with the engine vibration criteria.