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
Hard Landing
Boeing 737-700. Substantial damage. Eight minor injuries.
The first officer was the pilot flying during a domestic scheduled flight to La Guardia International Airport in Flushing, New York, U.S., the afternoon of July 22, 2013. Visual meteorological conditions prevailed at La Guardia, and the flight crew conducted a visual approach to Runway 04, using the instrument landing system (ILS) as a backup.
During their approach briefing, the pilots had agreed on a flap setting of 40 degrees. However, “the captain stated during post-accident interviews that, [at] some distance past the final approach fix, the pitch attitude did not look right to her and she noticed that the flaps were set to 30 degrees instead of 40 degrees, which the performance calculations for landing were based on,” said the report by the U.S. National Transportation Safety Board (NTSB).
The captain called out the anomaly and reset the flaps to 40 degrees as the 737 descended through a radio altitude of 500 ft. The report noted that this was contrary to company standard operating procedures (SOPs), which require a go-around if the airplane is not in the correct landing configuration by the time it is 1,000 ft above runway touchdown zone elevation.
The 737 was about 370 ft above the ground when the first officer disengaged the autopilot and initiated a sideslip to counter a slight right crosswind. He then noticed that the airplane was above the proper glide path and began to make airspeed and crosswind-control corrections.
The captain, who was using a head-up display to monitor the approach, judged that groundspeed was too fast, pitch attitude was too low and sink rate was insufficient as the airplane crossed the runway threshold.
The captain called out “100 feet” and told the first officer to “get down, get down, get down.” The airplane was 27 ft above the runway a few seconds later when she said, “I got it.” The first officer responded, “OK, you got it.”
“She said she believed that if she did not act, the airplane would have continued to float past the touchdown zone” of the 7,000-ft (2,134-m) runway, the report said.
After the captain reduced power, recorded flight data showed that “the airplane’s pitch began to enter a negative (nose down) trend that continued to decrease to a minimum airborne value of –3.87 degrees,” the report said. The throttles were advanced about one second before touchdown.
The nose landing gear collapsed when the airplane touched down 1,850 ft (564 m) from the runway threshold. The 737 then slid to a stop about 3,600 ft (1,097 m) right of the runway centerline.
The report noted that eight of the 149 people aboard the airplane sustained minor injuries but did not specify whether the injuries occurred during the hard landing or the subsequent evacuation.
The NTSB concluded that the probable cause of the accident was “the captain’s attempt to recover from an unstabilized approach by transferring airplane control at low altitude instead of performing a go-around” and that a contributing factor was “the captain’s failure to comply with SOPs.”
The report also said, “Accident data suggest that pilots often fail to perform a go-around or missed approach when stabilized approach criteria are not met. … Human factors researchers [have] found that about 75 percent of accidents were the result of plan-continuation errors in which the crew continued an approach despite cues that suggested it should not be continued.
“Additionally, line operations safety audit data presented at the [Flight Safety Foundation] International Air Safety Summit in 2011 suggest that 97 percent of unstabilized approaches were continued to landing even though doing so was in violation of companies’ SOPs.”
Tired, Sick and Hungry
Airbus A330-202. No damage. No injuries.
Insufficient sleep, lack of nourishment and a virus that likely reduced the captain’s performance capability, combined with ineffective monitoring of the aircraft’s flight path, led to close proximity with terrain during a visual approach to Melbourne Airport the afternoon of March 8, 2013, according to a report by the Australian Transport Safety Bureau.
On arrival, the flight crew had been asked by air traffic control (ATC) to expedite the descent and were cleared to navigate from an intermediate waypoint on the standard arrival route directly to the Runway 16 ILS final approach fix. The crew had expected this and had programmed an appropriate backup flight plan in the autoflight system.
The A330 was on a 45-degree angle to intercept the localizer course when the captain perceived that the aircraft was too high and increased the descent rate to 2,200 fpm. The report noted that although the aircraft was outside the ILS signal coverage area, the captain was using glideslope deviation indications — rather than other, more pertinent flight path information — to assess the aircraft’s vertical flight path. The likely spurious glideslope indications led the captain to perceive that the aircraft was high.
However, the first officer saw outside visual cues indicating that the aircraft was too low. The primary flight display confirmed the first officer’s perception, and he told the captain, “You are low.”
The A330 was descending through 1,800 ft at the time. “The captain reduced the rate of descent by selecting the autoflight vertical speed mode, but a short time later the enhanced ground-proximity warning system (EGPWS) provided ‘TERRAIN’ alerts followed by ‘PULL UP’ warnings,” the report said.
The flight crew immediately responded to the EGPWS warnings. The A330 was 600 ft above ground level and 9 nm (17 km) from the runway touchdown zone when they initiated a go-around. The pilots subsequently landed the aircraft without further incident.
The captain told investigators that he had had six hours of sleep, which was disrupted by cold symptoms that worsened later, as the day progressed. He also had no breakfast before the first leg from Perth to Sydney and no lunch before the flight to Melbourne.
Fuel Leak Causes Fire
Bombardier CRJ700. Substantial damage. No injuries.
Shortly after departing from Lyon, France, for a scheduled flight to Barcelona, Spain, with 32 passengers and four crewmembers the morning of Aug. 15, 2011, the pilots received warnings of a fire in the left engine. They shut down the engine, discharged both fire extinguishers, declared an emergency and returned to the airport.
After a safe single-engine landing, the passengers disembarked normally. An examination of the left engine revealed that the fuel supply line had disconnected from the operability bleed valve (OPV), according to the report by the French Bureau d’Enquêtes et d’Analyses.
“The OPV is a butterfly-type valve that allows air to be regulated in the compressor, controlled by a fuel supply under pressure,” the report said. The fuel supply line fitting had loosened and disconnected due to wear during more than 15,400 flight hours.
“Following this incident, the manufacturer selected another supplier who offered a more robust unit,” the report said. The U.S. Federal Aviation Administration subsequently issued an airworthiness directive requiring replacement of the OPVs on GE CF34-8C and -8E engines.
Turboprops
Salt Covers Windshield
ATR 72-212A. No damage. No injuries.
Winds from the southwest at 29 kt, gusting to 44 kt, prevailed at Cork (Ireland) Airport the night of Jan. 2, 2014, and the flight crew conducted a go-around after experiencing a significant increase in indicated airspeed during their first approach to Runway 25.
The crew told ATC that they would attempt another approach and were given vectors that placed the aircraft in a wide left-hand traffic pattern. On the downwind leg, “its track brought it south of [the airport], close to the coast and at times over the sea,” said the report by the Air Accident Investigation Unit of Ireland. “During this time, a thick layer of sea salt formed on the front windscreens, obscuring the flight crew’s forward visibility.”
This prompted the crew to conduct another go-around. The commander told ATC that the aircraft had flown through “something” that had sealed the windshield. “The wipers aren’t taking it off,” she said.
“ATC informed [the crew] of a similar situation in Shannon a couple of weeks earlier in high winds which turned out to be a film of sea salt on the windscreen,” the report said.
The controller was vectoring the ATR to the northwest, away from an arriving aircraft, when the crew saw a cell displayed on their weather radar 10 nm (19 km) ahead. The commander requested and received clearance to maintain their current heading so that they could fly to the edge of the cell, where rain might help clear the windshield.
The crew maneuvered the aircraft near the cell for about 10 minutes, and rain did clear a portion of the commander’s windshield. A rain shower encountered while returning to the airport cleared a larger area, and the ATR subsequently was landed without damage or injury to the 50 people aboard.
Visual in Blowing Snow
Beech 1900C. Substantial damage. No injuries.
Before departing on a charter flight from Deadhorse, Alaska, U.S., the afternoon of Nov. 22, 2013, the flight crew learned that visibility at the destination — Badami Airport, 29 nm (54 km) east — was 1 1/2 mi (2,400 m) in blowing snow.
Nearing the destination, the first officer radioed a weather observer, who reported that visibility had deteriorated to 3/4 mi (1,200 m). “The captain then informed the private weather observer that the flight would need at least 1 [mi/1,600 m] to land,” the NTSB report said. “A few minutes later, the weather observer informed the captain that the visibility had improved to 1 [mi].”
Although a global positioning system approach was available, the captain decided to conduct a visual approach. Investigators determined that visibility decreased to 1/2 mi (800 m) during the approach.
“The first officer reported that, during the approach, he became uncomfortable and voiced his concerns multiple times to the captain, who assured him that they were ‘fine,’” the report said. “The captain stated that the approach was normal until he had a ‘sinking sensation’ and realized that the airplane was too low.”
The main landing gear separated when the 1900 touched down short of the runway. The airplane then slid to a stop on the runway. Damage was substantial, but the pilots and their passenger were not hurt.
Out of Balance
Pilatus PC-12/47E. Minor damage. One minor injury.
The PC-12 entered a series of pitch oscillations after lifting off from Austin, Texas, U.S., for a charter flight with nine passengers the afternoon of Sept. 12, 2013. Several stall warnings occurred, and the pilot rejected the takeoff after the airplane settled back onto the runway.
The right main wheel assembly caught fire as the PC-12 was brought to a stop. One passenger sustained minor injuries, which were not explained by the NTSB report.
Investigators determined that there had been a change of passengers and carry-on baggage before the flight commenced, and the operator did not update the trip sheet to reflect the actual loading. The pilot subsequently miscalculated the airplane’s weight and balance, underestimating passenger weight by 263 lb (119 kg) and baggage weight by 490 lb (222 kg).
As a result, “the incident flight was about 4 inches [10 cm] aft of the aft center of gravity limit and about 100 lb [45 kg] above the maximum ramp weight of the airplane,” the report said.
Piston Airplanes
VMC Roll on Go-Around
Cessna 310Q. Destroyed. Two fatalities.
Inbound from Paris, the aircraft was observed to deviate left of the extended runway centerline on final approach to Hawarden Airport in Chester, England, enter a high nose-up pitch attitude and rapidly roll left on the morning of Nov. 15, 2013. The 310 then struck the ground left of the runway threshold in a steep nose-down, inverted attitude.
“The investigation concluded that the left engine lost power at a late stage of the approach due to fuel starvation,” said the report by the U.K. Air Accidents Investigation Branch (AAIB). “The pilot probably attempted a go-around manoeuvre, but the speed fell below the minimum single-engine control speed [VMC], causing him to lose control of the aircraft.”
The AAIB determined that the pilot had mismanaged the aircraft’s fuel system during the flight to Chester. He had planned for a two-hour, 41-minute flight, but the actual flight time was three hours and five minutes.
“It was not possible to establish what fuel load the pilot would have regarded as a minimum for takeoff,” the report said. “Considering the pilot’s known attitude to fuel prices and the fact that he established cheaper fuel was available at Hawarden, it is unlikely that he would have loaded more fuel than he considered necessary.
“The majority of usable fuel at the time of the accident was in the auxiliary tanks, which were not selected for engine feed. From the available evidence, it is probable that the pilot originally intended to complete the flight using fuel from the main tanks only and loaded them with what he considered to be a sufficient quantity.”
Investigators found no fuel remaining in the left main tank and only 6 L (2 gal) remaining in the right main tank; there was no sign of a fuel leak. The auxiliary tanks each contained 30 L (8 gal) of fuel.
Low Pass Into a Tower
Cessna 340A. Destroyed. Four fatalities.
Witnesses saw the 340 make a low-altitude, high-speed pass over the facilities of a gun club in Paulden, Arizona, U.S., and then turn back for another low pass the afternoon of Oct. 4, 2013. On the second pass, the airplane’s right wing struck a 50-ft (15-m) radio tower about 10 ft (3 m) from the top.
“After the impact, the airplane rolled to the right almost inverted and subsequently impacted trees and terrain approximately 700 ft [213 m] from the initial impact point,” the NTSB report said. The pilot and his three passengers were killed, but no one on the ground was hurt.
A witness told investigators that “about three to four years prior to this accident, the pilot, a client of the gun club, had ‘buzzed’ the club and had been told never to do so again,” the report said.
Ice Causes Control Loss
Beech 58 Baron. Substantial damage. No injuries.
The Baron was climbing in instrument meteorological conditions during an approximately 125-nm (232-km) private flight from Wheeling, Illinois, U.S., to Savoy, Illinois, the morning of Oct. 4, 2014, when it encountered icing conditions.
The pilot later told investigators that a light accumulation of ice formed on the leading edges of the wings and that activation of the deicing boots eliminated about 30 to 40 percent of the ice.
“The airplane then climbed to and leveled off at 10,000 ft, at which point the engine speed ‘fluttered’ and the airplane rolled ‘quickly to the left’ and entered a descending spin,” the NTSB report said.
The passenger, a certified flight instructor, took control and recovered from the spin at about 2,500 ft. Recorded ATC radar data showed that the airplane descended 7,500 ft in about 30 seconds. The pilot subsequently diverted to Dixon, Illinois, and landed the Baron without further incident.
“Post-accident examination and testing of the airplane revealed no mechanical anomalies that would have precluded normal operation,” the report said. “The examination revealed substantial damage to the right wing and elevator control surface, which was consistent with forces sustained from excessive accelerations.”
Helicopters
Tail Rotor Control Lost
Bell 206L-1. Destroyed. Three fatalities, one serious injury.
The pilot decided to reject an approach to a hospital helipad in Wichita Falls, Texas, U.S., the night of Oct. 4, 2014, because he believed the LongRanger was too high and too fast. Groundspeed was about 5 kt when he initiated the go-around by lowering the emergency medical services helicopter’s nose, increasing power and raising the collective.
The helicopter entered a rapid right spin, and the pilot attempted to recover by applying left anti-torque pedal and cyclic, the NTSB report said. However, the helicopter continued to spin and descended into power lines and terrain. The patient, flight nurse and paramedic were killed, and the pilot was seriously injured.
The NTSB determined that the pilot likely “did not adequately account for the helicopter’s low airspeed [and did not] maintain yaw control when he applied power to execute a go-around at a low airspeed in dark, night conditions.”
Downdraft Causes Drift
Robinson R44. Substantial damage. No injuries.
The pilot was conducting a private sightseeing flight to Cradock Peak, South Africa, the afternoon of Jan. 17, 2015. The R44 was on final approach to land at an elevation of about 6,000 ft when low-rotor-speed/blade stall warnings activated.
“The pilot instantly lowered the collective lever in an attempt to recover the rpm to the green arc, but without success,” said the report by the South African Civil Aviation Authority. The helicopter drifted and touched down hard, damaging the landing skids and lower fuselage, and the main rotor blades severed the tail boom.
“The helicopter remained upright, and the pilot and the passengers disembarked uninjured,” the report said. “The investigation concluded that the accident was caused by downdraft conditions in the area at the time the pilot was initiating the landing.”
Tie-Down Strap Overlooked
Bell 206B. Substantial damage. No injuries.
The pilot was distracted from his preflight preparations by a cell phone call and did not notice that the main rotor tie-down strap was still attached when he started the police helicopter’s engine at Spring, Texas, U.S., the morning of July 30, 2014.
The pilot noticed a person approaching the helicopter and waving his hands. He then heard a “thump” and conducted an emergency engine shutdown.
“Examination of the helicopter revealed that the tie-down strap had broken during the engine start and had gotten caught on the tail rotor output shaft, which resulted in substantial damage to the tail boom, tail rotor blades and vertical fin,” the NTSB report said.