The following information provides an awareness of problems that might be avoided in the future. The information is based on final reports by official investigative authorities on aircraft accidents and incidents.
Jets
No Real-Time Data
Airbus A320. Minor damage. No injuries.
French authorities said that the lack of equipment to remotely measure runway contamination and allow dissemination of real-time information on braking action to pilots was a causal factor in an overrun at Paris Orly International Airport the morning of March 12, 2013.
The incident involved an A320 that was en route to Paris from Tunisia with 140 passengers and six crewmembers. Precipitation in the form of freezing rain had begun to fall at Orly about 0530 local time and had changed to snow of varying intensities as the morning progressed, said the report by the Bureau d’Enquêtes et d’Analyses (BEA).
The A320 was about 45 minutes from the airport at 1030 when the flight crew listened to an automatic terminal information service (ATIS) broadcast stating that Runway 08, the only runway available at Orly, was covered with dry snow and that arriving pilots should plan to vacate the runway either on Taxiway W4, which is about halfway down Runway 08, or on Taxiway W31, which is at the end of the 3,320-m (10,893-ft) runway. Braking action was reported as “medium.”
A few minutes after receiving the ATIS message, the crew was told by air traffic control that braking action had been reported as “medium to poor” by the pilot of another aircraft. The A320 crew recalculated the required landing distance accordingly and discussed the risk of a runway excursion, the report said.
The crew flew a stabilized approach, touched down at the reference landing speed and deployed the thrust reversers. The copilot was the pilot flying, but, per standard operating procedure, the captain took control after touchdown. The report said that deceleration initially was “stable (around 0.3 g)” and the captain planned to turn off on Taxiway W4.
However, as the aircraft neared the mid-field taxiway, traveling at about 42 kt, the tower controller asked the crew to vacate the runway on Taxiway W31. “The crew continued rolling towards the end of the runway, located approximately 1,700 meters [5,578 ft] away,” the report said. “They found that the last third of the runway was not clean and that snow was present on the surface, unlike the touchdown zone.”
The captain began to apply the wheel brakes about 480 m (1,575 ft) from the taxiway, but deceleration was much less than expected. He increased brake pressure, but the aircraft did not slow down. The report said that deceleration was 0.12 g at a groundspeed of 35 kt.
The captain later told investigators that he felt “surprised and helpless” while trying to slow the aircraft. As a last resort, he engaged the parking brake and tried to control the aircraft’s path using the rudder pedals.
Groundspeed was 17 kt when the A320 overran the runway at 1115. It came to a stop four seconds later with minor damage to the nose landing gear. “The captain informed the controller that braking was ‘very, very poor,’” the report said.
The report noted that the most recent braking action measurement had been made about one hour before the incident. “The use of measuring equipment is highly disadvantageous from an operational perspective as it requires closing the runway for about 20 minutes,” the report said. “However, no remote real-time measuring equipment is available to date.”
In a statement of what likely caused the incident, the BEA said, “The inability to measure runway adherence in real time did not allow the uneven runway contamination to be detected. This led to the crew’s and controllers’ degraded perception of braking condition at the end of the runway, resulting in the overrun.”
Runaway Maintenance Van
Embraer 190. No damage. No injuries.
A technician for a charter aircraft operator exited a maintenance van to help personnel who were preparing a Boeing 737 for departure from Gate H16 at Toronto (Canada) Lester B. Pearson International Airport the night of March 11, 2013.
The van’s engine was running, but the technician apparently didn’t realize that the automatic transmission was in drive. “When the technician eventually exited the aircraft, he noticed that the vehicle was nowhere in sight,” said the report by the Transportation Safety Board of Canada.
The driverless van traveled in nearly a straight line from the gate and onto a taxiway leading to the approach threshold of Runway 24R. The Embraer, with 67 passengers and five crewmembers aboard, was on short final approach to the runway.
As the van neared the runway, an airport ground traffic controller noticed a corresponding target on the airport surface detection equipment radar display. He alerted the tower controller, who told the flight crew of the Embraer to go around.
“The flight crew did not respond to the call, and [the controller] again instructed the aircraft to pull up and go around,” the report said. “The flight crew did not respond and … flew directly overhead the van, separated by approximately 35 feet, and landed on Runway 24R.”
The van ran off the side of the runway and became mired in a wet grassy area after striking a taxiway sign.
The pilots told investigators that they had not seen the van. Investigators determined that the controller’s first instruction to go around likely was blocked by a louder automatic height callout generated in the Embraer’s cockpit. The crew said that they heard only the words “go around” in the controller’s second radio transmission and decided that the call was not for them.
‘No Firm Plan’
Bombardier Challenger 604. Substantial damage. No injuries.
The flight crew and an engineer took off from Biggin Hill Airport in Kent, England, the afternoon of March 26, 2014, to conduct a post-maintenance test of the air-driven generator (ADG) during one circuit of the traffic pattern.
However, there was “no firm plan” for conducting the test and no clear understanding of the roles that the two pilots and the engineer would play during the brief flight, said the report by the U.K. Air Accidents Investigation Branch.
Although a checklist for the ADG test was available, the pilots expected to be guided through the procedure by the engineer. However, the engineer believed that his role was only to observe.
“After takeoff, the pilots maintained the takeoff flap setting of 20 degrees required for the ADG test,” the report said. “During the downwind leg, the flight crew took the main aircraft generators off line, thus simulating the failure conditions which would cause the ADG to deploy. Correct deployment and functioning of the ADG was confirmed.”
The generators were not re-engaged, however, and the electrical system remained in the emergency mode, in which the flaps, ground spoilers, anti-skid braking system and nosewheel steering system are rendered inoperative.
The crew attempted unsuccessfully to extend full flaps for landing, and only one thrust reverser deployed after the Challenger touched down at about 150 kt. Using maximum wheel braking, the crew brought the aircraft to a stop about 120 m (394 ft) from the end of the 1,550-m (5,086-ft) runway.
Examination of the Challenger showed that all four tires on the main landing gear had ruptured and that the left wheel and brake had been damaged during the landing.
Turboprops
Ambiguous Clearance
Beech 1900C. Destroyed. Two fatalities.
The flight crew was conducting a cargo flight in instrument meteorological conditions the morning of March 8, 2013, from King Salmon, Alaska, U.S., to Dillingham. The airplane was at 6,000 ft and about 30 nm (56 km) southeast of the airport when the crew requested clearance to navigate directly to “ZEDAG,” an initial approach fix for the global positioning system (GPS) approach to Runway 19.
The controller approved the request and told the crew to “maintain at or above 2,000 feet until established on a published segment of the approach.”
This was an “ambiguous” instruction that elicited an unsafe response by the flight crew, according to the report by the U.S. National Transportation Safety Board (NTSB), which said that the controller should have cleared the crew to proceed direct to ZEDAG and to enter the terminal arrival area south of ZEDAG at or above 5,400 ft, as published on the approach chart.
The crew read back the ambiguous clearance and began a descent. Six minutes later, they requested clearance to hold at ZEDAG while they used another radio frequency to check on runway conditions. The controller told the crew to “hold as published.” At the time, the airplane was at 2,200 ft. The published minimum altitude for the holding pattern at ZEDAG was 4,300 ft.
The crew’s apparent lack of awareness of the published altitude restrictions indicated that they did not review or brief the approach procedure before initiating the premature descent, the report said.
The report also said that the controller did not properly monitor the flight’s progress: Although the airplane’s trajectory generated minimum safe altitude aural warnings and visual warnings on the radar display, the controller did not issue any terrain warnings or climb instructions to the crew.
Shortly after the crew received the clearance to hold, the 1900’s radar target disappeared from the controller’s display. An emergency locator transmitter signal was received, but weather conditions prevented location of the airplane until the next morning.
“Examination of the wreckage and debris path evidence is consistent with the airplane having collided with rising terrain at 2,000 feet while flying in a wings-level attitude on the outbound leg of the holding pattern, which the flight crew should have flown at 4,300 ft,” the report said.
Improper Tooling
Piaggio P180. Minor damage. No injuries.
Shortly after touching down on the runway at St. Petersburg–Clearwater (Florida, U.S.) International Airport the afternoon of April 24, 2013, the pilot heard a tire squeal and felt the airplane begin to veer right.
“The pilot attempted to correct the turn by applying left rudder, left braking and left-engine thrust reverse,” said the NTSB report. “The airplane came to a stop with the nose pointed more than 90 degrees right of the runway centerline.” The nose landing gear received minor damage, but the pilot and his five business passengers were not hurt during the incident.
Investigators found that a recent overhaul of the nosegear steering manifold had not been conducted in accordance with the manufacturer’s component maintenance manual (CMM). “The overhaul facility used unapproved alternative tooling because it did not have the required tooling to conduct the overhaul as specified in the CMM,” the report said, noting that internal damage from tooling marks caused the steering manifold to fail during the landing.
Collision With Deicing Truck
Boeing DHC-8-102. Substantial damage. No injuries.
Inadequate communication among ground personnel resulted in a collision between the Dash 8 and a deicing truck at Tri-State Airport in Huntington, West Virginia, U.S., the morning of Jan. 16, 2012, according to the NTSB report.
The airport recently had changed from on-gate to off-gate deicing, and the Dash 8 captain had told a ramp agent that he would taxi out with one engine operating and feather the propeller while the airplane was being deiced. The ramp agent conveyed the pilot’s intentions to other ground personnel and returned to the operations station.
As the airplane was taxied from the gate, a ground crewmember stood by a wing to ensure clearance from parked equipment. The crewmember gave a thumbs-up signal to the flight crew when the airplane was clear of the equipment. The pilot then taxied a short distance and stopped to await further radio instructions from the ramp agent.
“Unknown to the flight crew, the deicing team misunderstood the thumbs-up signal to mean that deicing could begin,” the report said. “Consequently, they moved [the deicing truck, which was not radio-equipped] into a position behind the airplane’s left wing and in front of the left horizontal tail.”
Meanwhile, the ramp agent, who could not see the Dash 8 from the operations station and believed that it was still parked at the gate, told the crew to taxi 50 ft (15 m) and stop for deicing.
The flight crew felt a jolt when they began to taxi and immediately stopped the airplane. The left horizontal stabilizer and elevator had been substantially damaged when they struck the deicing truck’s boom arm. None of the ground personnel or the 36 people aboard the airplane was injured.
Piston Airplanes
Ice Chokes Engine
Piper Aztec. Substantial damage. No injuries.
The pilot was conducting a business flight at 9,000 ft from Jamestown, North Dakota, U.S., to Buffalo, Minnesota, the evening of March 15, 2013. During descent, the Aztec entered clouds at 7,500 ft. A temperature inversion apparently existed, because the pilot told investigators that the airplane initially encountered rain but then entered moderate to severe icing conditions below 5,000 ft.
“He activated the airframe deicing system four to six times before descending below the clouds at 3,300 ft,” the NTSB report said. “He stated that he could not see through the windshield due to a thick covering of ice but that he had good visibility to each side.”
The pilot canceled his instrument flight rules flight plan. Soon thereafter, the right engine lost power. “He attempted to restart the engine, including switching fuel tanks, activating the alternate air system and using both hot- and cold-start procedures, to no avail,” the report said.
The pilot diverted to the airport in Winsted, Minnesota, but had to make a forced landing short of the runway. The Aztec was substantially damaged, but the pilot and his five passengers escaped injury.
Examination of the airplane revealed that the right engine’s induction air filter was completely obstructed by ice and that the left engine’s filter was about 35 percent obstructed. “It is likely that the icing of the right engine’s induction air system resulted in a lack of airflow in the system, which prevented combustion and led to the subsequent loss of engine power,” the report said.
Dark Night, Unstable Approach
Partenavia P-68. Substantial damage. No injuries.
The pilot told investigators that he used his GPS receiver to align the airplane with the runway during an approach to the airport in Molokai, Hawaii, U.S., the night of Feb. 27, 2014.
“When the pilot activated the runway lights, the airplane was about 1/4 mile [402 m] to the left of the runway and 1/2 mile [805 m] from the approach end,” the NTSB report said, noting that he subsequently performed “aggressive” maneuvers to align the airplane with the runway. The right wing struck treetops at 50 ft, and the Partenavia descended rapidly to the ground. Damage was substantial, but the pilot was not injured.
NTSB concluded that the probable cause of the accident was “the pilot’s inadequate decision to continue an unstable approach in dark night conditions.”
Aerobatics Go Awry
Piper Aerostar 601P. Destroyed. One fatality.
The pilot had told a friend that he would fly a newly purchased airplane over his house in Aurora, Colorado, U.S., the afternoon of March 19, 2014. “The pilot’s friends and several other witnesses reported observing the pilot performing low-level, high-speed aerobatic maneuvers before the airplane collided with trees and then terrain,” the NTSB report said.
A whiskey bottle was found in the wreckage, and toxicological examination of the pilot’s remains revealed a blood alcohol content that was more than six times greater than the limit specified by U.S. Federal Aviation Regulations, the report said.
Helicopters
Control Loss in a Whiteout
Eurocopter EC155-B, AS332-L1. Substantial damage. One fatality, four serious injuries, five minor injuries.
Three German federal police helicopters were conducting an exercise to transport police officers from Blumberg, Germany, to the railway station at Olympia Stadium in Berlin the morning of March 21, 2013.
Three buses with flashing blue lights and three marshallers wearing yellow reflective vests and safety helmets were positioned at one end of a snow-covered field to aid the helicopters’ approaches, said the report by the German Federal Bureau of Aircraft Accident Investigation (BFU).
The pilot of the first helicopter in formation, the EC155-B, landed in front of the center marshaller and bus. Just before touchdown, the helicopter was engulfed in snow recirculated by the rotors. “On enquiry by the BFU, the flight engineer stated that he had been surprised by the snow depth and the recirculating snow because the crew had assumed slush or wet snow.”
The second helicopter, an AS332-L1, hovered for about 30 seconds while maneuvering to land before touching down to the right of the first helicopter. An audio recording captured the pilot of the first helicopter commenting on the resulting whiteout conditions: “One has no reference point anymore. … This is very dangerous.”
Meanwhile, the third helicopter, also an AS332-L1, was approaching to land to the left of the first helicopter. “It also caused recirculating snow which engulfed the marshaller and the two helicopters already on the ground,” the report said. The third helicopter drifted right and rolled over when the nosewheel and right main landing gear contacted the ground.
Debris struck and killed the pilot and seriously injured two passengers aboard the first helicopter; two bystanders also were seriously injured. Three other bystanders and the pilot and flight engineer aboard the third helicopter sustained minor injuries.
The BFU concluded that the accident was caused by the third helicopter pilot’s loss of orientation and control in whiteout conditions.
Turbine Case Eroded
Eurocopter SA315-B. Substantial damage. No injuries.
The pilot was flying the helicopter 300 ft above the ground near Alva, Oklahoma, U.S., the morning of March 30, 2012, when he heard a loud noise and saw rotor speed begin to decrease. He jettisoned the external load and initiated an autorotation to an open field.
“During the flare, the helicopter’s main rotor blades contacted the tail rotor drive shaft,” the NTSB report said. “Engine disassembly and examination revealed that the turbine casing was deeply eroded by particles that had accumulated in the casing as a result of operating in dusty environments.” The erosion had caused the case to crack, resulting in uneven heating that led to partial melting of the nozzle guide vanes and rupture of blade tips in all three turbine stations. The debris punctured the turbine casing and shroud.
“Maintenance records contained no entries pertaining to compliance with the manufacturer’s maintenance procedures, by either the current or previous [helicopter] owner, for operations in sandy environments,” the report said.