Preliminary Reports
L-39 Crashes After Low Pass
Aero Vodochody L-39, Oct. 8, 2017, Vernon, Texas—The 1984-vintage jet trainer crashed half a mile south of the Wilbarger County Airport in Vernon, Texas, killing its pilot and owner, a local dentist. At least nine witnesses saw the jet make a low pass over Runway 20 with the landing gear extended. Some reported that the gear began to retract as if for a go-around. The airplane rolled into a a steep left bank as it pulled up, hitting the ground left wing first.
The 40-foot ground scar left by the wingtip led to a 50-foot crater at the beginning of a 584-foot debris path. Damage to the engine compressor was consistent with sudden stoppage. A grass fire resulting from the fuel spill was quickly extinguished by first responders.
King Air Strikes Drone on Approach
Beechcraft King Air A100, Oct. 12, 2017, Quebec City, Quebec—At the end of an IFR flight from the Rouyn-Noranda airport to Quebec City, a King Air A100 struck an unmanned aerial vehicle with the end of its left wing. The turboprop twin had just passed the final approach fix for Runway 24 when the crew saw the conflicting aircraft. Airport firefighting and rescue was deployed after the crew declared an emergency, but the landing was uneventful. The collision occurred at 1,500 feet. Damage was limited to scratches and paint transfer on the upper wing skin and scrapes on the de-icing boot. No injuries were reported among the two crewmembers and six passengers on board.
Linemen Killed in External Load Accident
Hughes 369D, Sulphur, Louisiana, Nov. 7, 2017—Two power-company linemen died after the long line used to hoist them was severed in a collision with a powerline shield wire. The purpose of the flight was to install guard ropes between three sets of de-energized transmission lines before the existing shield wire was disconnected. According to the pilot, contact with the shield wire occurred while one of the linemen pulled on the northernmost bundle of cables in an effort to turn the guard rope perpendicular to the conductors. The linemen fell about 100 feet; the helicopter returned for an uneventful landing.
Loose Seat Causes Runway Excursion in Ghana
Aerospatiale/Aeritalia ATR 72-500, Accra-Kotoka, Ghana, Nov. 25, 2017—Before the regional turboprop reached 70 knots on the takeoff roll on a domestic passenger flight, the captain’s seat abruptly moved backwards and to the left. The captain’s grip on the nosewheel tiller caused the airplane to veer left and depart the side of the runway. It came to a halt just short of the airport perimeter fence after the first officer closed the throttles. Every blade of the left propeller was damaged by contact with barbed wire. There were no injuries to the five crewmembers and 63 passengers.
Final Reports
Hypoxia Blamed in Fatal TBM 900 Crash
Daher-Socata TBM 900, Sept. 5, 2014, 20 miles north of Jamaica, West Indies—The fatal crash of a Daher TBM 900 in the waters north of Jamaica was the result of pilot incapacitation due to hypoxia following the loss of cabin pressure, according to the NTSB. While in cruise flight from Rochester, New York, to Naples, Florida, at FL280 the pilot apparently noted warnings on the crew alerting system and requested a lower altitude from ATC but did not declare an emergency or immediately begin using supplemental oxygen. Due to conflicting traffic, ATC was initially able to authorize only a descent to FL250; the pilot acknowledged but did not execute subsequent descent clearances. Radio contact was lost four and a half minutes after his initial descent request and the airplane continued flying straight and level at FL250 for another four hours before descending rapidly into the ocean after apparently exhausting its fuel.
Two teams of military pilots who intercepted the TBM and paced it from South Carolina to the edge of Cuban airspace reported that the occupants appeared to be unconscious. Neither was wearing an oxygen mask. Fragments of wreckage recovered from the sea floor four months later included the pressurization system’s global air system controller (GASC). Fault codes recorded in its non-volatile memory showed that the overheat thermal switch had activated, shutting off the engine bleed air system. Manufacturer test data indicates that at FL280, cabin pressure would bleed down to atmospheric pressure in about four minutes with the bleed air system disabled. The first evidence of cognitive impairment in the pilot’s radio transmissions came two minutes and 30 seconds after he requested a descent.
The owner and pilot of N900KN was real-estate developer Larry Glazer, then chairman of the TBM Owners and Pilots Association. He was accompanied by his wife, Jane, who was also qualified to act as PIC of the airplane. Glazer, 68, had accumulated more than 4,000 hours in the three TBM 700-series airplanes he’d owned since 1994 but had not taken altitude chamber training in at least a decade. The NTSB noted that only 90 minutes of the five-day recurrent training course he’d completed one week before the accident dealt with the airplane’s pressurization system, and that only one of the four relevant checklists in the 656-page Pilot’s Operating Handbook included a “suggestion” of going onto supplemental oxygen. Following the accident, Daher revised the POH to make donning oxygen masks the first step in every relevant emergency checklist and announced that it would retroactively make the same revisions to the POHs of earlier models.
Pilots Failed To Extend Merlin Gear
Swearingen SA-26AT, July 28, 2017, Hondo, Texas—The NTSB attributed the gear-up landing of a Swearingen Merlin IIB during dual instruction in the traffic pattern to the commercial pilot receiving instruction having forgotten to extend the landing gear, a lapse that went unnoticed by both the multi-engine instructor supervising the flight from the right seat and a second MEI observing from the first row of the passenger compartment.
The left-seat pilot recalled the gear retracting spontaneously following a hard touchdown and bounce during a no-flaps landing. He acknowledged, however, that “human memory often performs poorly when remembering unexpected and stressful events…I may have failed to deploy the landing gear.” He did not remember hearing the gear horn. A CFI taxiing out with a student saw the Merlin descending through 400 agl on final with the gear retracted, but assumed it was doing a low approach. The FAA inspector who responded to the scene found the gear selector in the UP position.
No injuries resulted, but damage to the fuselage was deemed “substantial.”
Failure of Tail Rotor Drive Shaft Traced to Missing Fasteners
Bell 206L-3, Oc. 15, 2015, Dickinson, Alabama—A loss of tail rotor thrust during low-altitude aerial application was caused by the departure of one of two bolts and self-locking nuts that secure the aft end of the S1 tail rotor driveshaft to the disk coupling, the NTSB determined. Loss of the fasteners allowed the driveshaft, the first segment aft of the oil cooler blower, to go out of alignment with its axis of rotation, causing the subsequent fracture of three of four driveshaft sections. The S3 shaft remained intact.
Wear on the hole through which the missing bolt had been installed indicated contact with the bolt's threads. The prevailing torque measured on two of the remaining three locknuts (a measure of their resistance to turning) was below the minimum limit specified in Bell’s Standard Practices Manual, and the NTSB report notes that turning resistance generally decreases when locknuts are reused. The helicopter had flown 490 hours and completed four 100-hour inspections since undergoing modifications that required removal and reinstallation of the engine, oil cooler and blower assemblies, tail rotor driveshafts between the engine and oil cooler and aft of the oil cooler blower (the S1 shaft), and the tailboom. The helicopter’s maintenance records didn’t specify whether the associated hardware was reused or replaced.
According to the pilot, he was flying between 70 and 120 feet above the tree line at about 15 knots when he heard a “pop” and lost all tail rotor authority. He lowered the collective without retarding the throttle and the main rotor blades, mast, and tailboom were damaged by contact with the trees. The helicopter came to rest on its left side; the pilot was not injured.
The hazard posed by the loss of hardware from tail rotor driveshaft couplings in the Bell 206/206L was the subject of a Civil Aviation Safety Alert issued by Canada’s Transportation Safety Board in March 2017 and an FAA Special Airworthiness Information Bulletin in November 2017. Both recommend avoiding the reuse of self-locking nuts and painted torque stripes to detect loosening between inspections.
Inappropriate Use of Emergency Brakes Caused Overrun
Embraer EMB-500, Nov. 21, 2014, Sugar Land, Texas—The pilot-in-command’s use of the Phenom 100’s emergency/parking brake (EPB) on a wet runway compounded the difficulty of stopping after an excessively fast approach, causing the very light jet to slide off the end of the runway and across a service road into a drainage ditch. No injuries resulted from the accident, which occurred at the end of a short IFR positioning flight from Houston Hobby to Sugar Land Regional. Light rain and mist were present, but the tower controller reported “no standing water” on the runway. The NTSB’s investigation found that application of the EPB defeated the main braking system’s anti-skid protection and locked the main wheels, causing reverted rubber hydroplaning. It also concluded that the airplane should have been able to stop 795 feet before the end of the runway using maximum application of the toe brakes.
The airplane’s flight data recorder (FDR) showed that at 50 feet above touchdown zone elevation its airspeed was 118 knots, 17 knots faster than VREF and seven knots above the speed at which the operator’s SOPs called for an automatic go-around. At touchdown 1,040 feet past Runway 35’s displaced threshold, the FDR showed 104 knots indicated airspeed and a seven-knot tailwind. The available stopping distance was just under 5,000 feet. Brake application reached maximum 7.5 seconds after the nose gear touched down. During that time, both pilots expressed concern about the apparent lack of deceleration. The pilot activated the EPB four seconds later, at which time the FDR showed wheel speed dropping abruptly from 70 knots to zero and an ANTI-SKID FAIL message on the crew alerting system. The airplane went off the runway at about 30 knots.
The flight was operated by Superior Air Charter, doing business as JetSuite Air. The pilot had more than 6,300 hours of flight experience that included more than 1,100 in type, and more than 800 of the copilot’s 4,200 total hours were also in the Phenom 100. The NTSB noted that neither U.S. nor Brazilian certification regulations required testing or publishing stopping distances on wet runways. To satisfy the European Aviation Safety Agency’s requirement for such data, Embraer proposed using 125 percent of the unfactored dry landing distance, which EASA accepted. The NTSB suggested that these figures led the pilots to expect a higher runway friction level and consequently more rapid deceleration than actual conditions permitted, leading to the perception of inadequate braking performance and the decision to engage the EPB. Embraer subsequently issued Flight Operations Letter PHE505-018/14, “Landing Procedure Best Practices and Recommendations," reminding operators that “The emergency parking brake will always deliver worse performance when compared to the normal brakes with anti-skid protection. Its use is only recommended on abnormal conditions, when the BRK FAIL CAS message is annunciated. In these conditions, applying the landing correction factors determined by the QRH is mandatory.”