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.
Go-Around Too Late
Boeing 737-800. Substantial damage. Four serious injuries.
The 737 was on a scheduled passenger flight the afternoon of April 13, 2013, from Bandung, Indonesia, to Bali, where visual meteorological conditions prevailed with a few thunderstorms in the area. The second-in-command (SIC) was the pilot flying (PF) when the flight crew began the VOR/DME (VHF omnidirectional radio/distance measuring equipment) approach to Runway 09 at Bali’s Ngurah Rai International Airport.
The aircraft was on final approach, about 900 ft above the Bali Sea, when the SIC announced that he did not have the runway in sight. The pilot-in-command (PIC) replied that he had the approach lights in sight and told the SIC to continue the approach.
The PIC then noticed a “dark area” ahead on the right side of the approach path. “The PIC predicted that the dark area was narrow and the runway would be visible after a short time,” said the report by the National Transportation Safety Committee of Indonesia (NTSC). The dark area actually was a thunderstorm moving north over the airport.
The cockpit voice recorder captured the sound of rain striking the windshield as the aircraft descended through 200 ft. The PIC told investigators that the outside environment then became “totally dark,” and he took control from the SIC.
The 737 was about 20 ft above the sea when the PIC initiated a go-around. The aircraft struck the water almost immediately thereafter. Four passengers were seriously injured; the other 97 passengers and seven crewmembers sustained minor or no injuries. “The aircraft was substantially damaged and submerged in shallow water,” the report said.
The NTSC concluded that factors contributing to the accident were that the pilots did not receive timely and accurate information about the weather conditions at the airport; they did not notice that the approach became unstabilized, with a descent rate exceeding 1,000 fpm below the minimum descent height; they “lost situational awareness in regards to visual references” when the aircraft entered the thunderstorm; and the decision to go around was made at an altitude that “was insufficient for the go-around to be executed successfully.”
Boeing 737-300F. No damage. No injuries.
The load order form for the cargo flight from Edinburgh, Scotland, to London the morning of Nov. 19, 2013, showed that the eight unit load devices (ULDs) were to be loaded in descending weight order, with the heaviest toward the rear of the aircraft.
However, neither the loading team nor the flight crew noticed that the ULDs inadvertently were loaded in the reverse order, which resulted in the center of gravity being more than 12 units beyond the forward limit. “The commander stated that, because the turnaround had been rushed due to the late arrival of the load and fuel, this check had not been carried out,” said the report by the U.K. Air Accidents Investigation Branch.
On takeoff, the commander had to apply greater-than-normal back pressure on the control column to rotate the aircraft, and more-than-usual nose-up pitch trim was required during the climb. “The crew discussed the situation and concluded that there may have been a loading error,” the report said. “However, as the aircraft was apparently flying normally, they elected to continue to the destination.”
An abnormal amount of nose-up pitch trim was required during cruise flight and the subsequent approach, but the freighter was landed without further incident at London Stansted Airport.
“In order to prevent a reoccurrence, the operator now requires a flight deck crewmember to check each ULD number as it is loaded and has adopted a ‘pyramid’ loading system whereby the heaviest ULDs are loaded towards the centre of the aircraft in order to mitigate the effects of any errors,” the report said.
Boeing 747-400. No damage. No injuries.
The aircraft was crossing the east coast of North America during a scheduled passenger flight from Newark, New Jersey, U.S., to Frankfurt, Germany, the night of Nov. 18, 2012, when the first officer, the PF, told the commander that he was feeling tired and wanted to rest for 10 minutes. The commander took control of the 747.
“After the first officer woke up, he reported that he was still feeling very tired, dizzy and had difficulties concentrating,” said the report by the Air Accident Investigation Unit of Ireland. The purser obtained the assistance of three physicians among the passengers to attend the 35-year-old first officer in the crew area behind the cockpit.
“The first officer slept again, but when he awoke he complained of a severe headache and commenced vomiting,” the report said. “The principal doctor … then advised that the first officer would be unable to return to his duties and that he should be removed to hospital.”
At the time, the 747 was about halfway across the Atlantic. The commander decided to declare an emergency and divert the flight to Dublin, Ireland. The passenger list showed that several airline pilots were aboard, including a 767 captain for another airline. “The commander, having checked this captain’s pilot’s license and identity, ascertained that he could assist him on the flight deck and allowed him to sit in the first officer’s seat while performing PM [pilot monitoring] duties under his command and supervision,” the report said.
The 747 was landed in Dublin without further incident, and the first officer was transported to a hospital. A relief crew later arrived to complete the flight to Frankfurt. The report did not specify the first officer’s illness but noted that he received further medical examination and treatment in Ireland and in Germany.
Setup for an Overrun
Learjet 25B. Substantial damage. No injuries.
The absence of company guidance for landing with a tail wind on a wet runway, a malfunctioning anti-skid braking system and a late touchdown were among the elements involved in the Learjet’s overrun at Portland-Hillsboro (Oregon, U.S.) Airport the afternoon of Nov. 17, 2010, according to the U.S. National Transportation Safety Board (NTSB).
The flight crew, who were completing a positioning flight, conducted a VOR/DME approach to Runway 30 with an 8-kt tail wind. “Despite the tailwind, the captain elected to land on the 6,600-foot [2,012-m] runway instead of circling to land with a headwind,” the NTSB report said. “Moderate to heavy rain had been falling for the past hour, and the runway was wet.”
The first officer had consulted the company’s landing data card and had calculated a landing distance of 4,538 ft (1,383 m) on the wet runway. However, unlike the airplane flight manual (AFM), the company card did not provide corrections for tail winds. Investigators found that the wet stopping distance with an 8-kt tail wind was 5,110 ft (1,558 m).
The pilots later told investigators that the Learjet touched down about 1,200 ft (366 m) beyond the approach threshold. The spoilers were extended and brake pressure was applied, but there was no discernable deceleration. “The captain stated that he thought about performing a go-around but believed that insufficient runway remained to ensure a safe takeoff,” the report said.
The anti-skid braking system did not function properly, and the Learjet hydroplaned on the wet runway. It then overran the runway at about 85 kt and traveled about 618 ft (188 m) on wet terrain before striking a drainage ditch, collapsing the nose landing gear.
The NTSB concluded that the probable cause of the accident was the PF’s “failure to attain the proper touchdown point.” Contributing factors were the company’s deficient landing data card and the malfunctioning anti-skid system.
‘It’s No Problem’
Socata TBM 700. Destroyed. Five fatalities.
The pilot of the turboprop single reported light icing conditions while climbing on a flight from Teterboro, New Jersey, U.S., to Atlanta, Georgia, the morning of Dec. 20, 2011. The controller asked the pilot to tell him if the conditions worsened, and the pilot replied, “We’ll let you know what happens. … If we can go straight through, it’s no problem for us.”
Shortly thereafter, while cruising at 17,000 ft, the pilot requested clearance to climb to a higher altitude as soon as possible. The controller asked the pilot to stand by and, after coordinating with the controller of an adjacent sector, cleared him to climb to 20,000 ft.
Recorded radar data showed that the TBM 700 subsequently entered a steep left turn at 17,800 ft and descended rapidly. Investigators determined that the airplane broke up before striking the median of a highway near Morristown, New Jersey.
The NTSB concluded that the probable causes of the accident were “the airplane’s encounter with unforecast severe icing conditions … and the pilot’s failure to use his command authority to depart the icing conditions in an expeditious manner, which resulted in loss of airplane control.”
Loose Injector Causes Fire
ATR 72-212A. Minor damage. No injuries.
The flight crew was starting the left engine in preparation for a scheduled passenger flight from Moorea, French Polynesia, the morning of Nov. 18, 2011, when they noticed that the inter-turbine temperature increased more slowly than normal and then stagnated between 300 and 400 degrees C (572 and 752 degrees F). Engine speed also stagnated between 30 and 40 percent.
“The captain was thinking of abandoning the start-up sequence when the engine fire alarm came on,” said the report by the French Bureau d’Enquêtes et d’Analyses. “He applied the engine ground fire procedure and fired extinguisher no. 1 without success. Firing the second extinguisher put out the fire.” The passengers subsequently were evacuated without incident.
Investigators found that the fire had been caused by a fuel leak emanating from a damaged O-ring in a fuel injector that had not been tightened properly during maintenance. The report noted that the engine manufacturer, Pratt & Whitney Canada, subsequently published a service bulletin clarifying procedures for installing and leak-checking the injectors in PW120 engines.
Ice Triggers Control Loss
Beech King Air F90. Destroyed. One serious injury.
Light freezing drizzle had been forecast along the route from Wharton to Midland, both in Texas, U.S., the morning of Dec. 2, 2011. The pilot told investigators that despite the use of all the ice-protection systems, the King Air accumulated moderate to severe airframe icing as it neared the destination, which was reporting 1 3/4 mi (2,800 m) visibility in mist and an 800-ft overcast.
During the subsequent global positioning system (GPS) approach to Runway 25 at Midland Airpark, the airplane deviated from the published course. The approach controller canceled the pilot’s approach clearance and provided vectors to position the King Air for another attempt.
During the second approach, the controller advised the pilot that the airplane was about a half mile south of course and provided heading and climb instructions for a missed approach.
Although the AFM prohibits the use of the autopilot in icing conditions because it can mask tactile clues to adverse changes in handling characteristics, the pilot continued the approach with the autopilot engaged. He also conducted the approach at airspeeds ranging from 120 kt to 100 kt, which are below the AFM’s recommended minimum airspeed of 140 kt for sustained flight in icing conditions.
“The airplane descended under the cloud deck, and the pilot began to look for the runway,” the NTSB report said. He advanced the power levers, and the airplane abruptly rolled about 90 degrees left. “He disengaged the autopilot and attempted to use the yoke to level the airplane. The airplane then rolled about 90 degrees to the right. The pilot was unable to regain airplane control, and the stall-warning horn came on seconds before the airplane impacted the ground.”
The King Air crashed into a house about a mile from the runway, and a fire erupted. Although seriously injured, the pilot was able to exit the airplane. No one on the ground was injured.
The NTSB concluded that the probable causes of the accident were “the pilot’s failure to maintain the recommended airspeed for icing conditions and his subsequent loss of airplane control while flying the airplane under autopilot control in severe icing conditions, contrary to the airplane’s handbook.” A contributing factor was “the pilot’s failure to divert from an area of severe icing.”
Fuel Selector on Empty Tank
Piper Chieftain. Destroyed. No injuries.
The Chieftain was climbing through 9,000 ft during a flight from Gauteng, South Africa, to Limpopo the morning of Nov. 25, 2012, when the left engine lost power. The pilot feathered the propeller and turned back to Gauteng, but he was unable to maintain altitude.
“The pilot realised he was losing height rapidly and decided to do a wheels-up forced landing in an open field 1 nm [2 km] north of Gauteng,” said the report by the South African Civil Aviation Authority (CAA). “As the pilot was about to land the aircraft, a fire erupted in the right engine and continued until touchdown.” After the Chieftain came to a stop in the field, the pilot exited before the fire engulfed the aircraft.
Investigators found both fuel selectors positioned to the main tanks. The left main tank was empty, but the left outboard tank was full. The CAA concluded that the left engine had failed due to fuel starvation. The cause of the fire in the right engine could not be determined.
Load Shifts on Takeoff
Douglas DC-6. Substantial damage. No injuries.
Shortly after departing from Nuiqsut, Alaska, the night of Nov. 25, 2013, to deliver a load of oversized oil-drilling tools to Deadhorse, the first officer, the PF, noticed that elevator control was “momentarily stiff.”
The flight engineer inspected the cargo and found that two of the four 31-ft (9-m) drilling tools had shifted aft and damaged the aft pressure bulkhead. “The captain did not declare an emergency, and the airplane landed at the destination without incident,” the NTSB report said.
Examination of the cargo revealed that some of the nylon straps securing the drilling tools likely had loosened slightly during taxi and takeoff. “The crew also noted that the drilling tools were covered with ice and snow, which likely aided the tools in sliding along the aluminum, diamond-plate-covered floor of the airplane,” the report said.
Night-Flight Decision Faulted
Cessna 421C. Destroyed. Two fatalities.
One of the airplane’s two vacuum pumps had failed on a previous flight, and the pilot was unable to have it repaired before departing from Salinas, California, U.S., for a flight to Omaha, Nebraska, the night of Nov. 10, 2012.
Recorded radar data showed that shortly after leveling at 27,000 ft, the 421 rolled right and entered a rapid descent. The airplane subsequently broke up before striking terrain near Shaver Lake, California.
“The breakup sequence was most likely inadvertently induced by the pilot as he attempted to recover control of the airplane during the dive,” the NTSB report said. “The airplane was flying toward an uninhabited mountain range and a largely unpopulated desert area at the time of the upset. The moon had set, and the pilot would have had limited reliable external visual cues should the airplane have experienced a failure of either the flight instruments or the autopilot.”
The NTSB determined that a contributing factor in the accident was “the pilot’s decision to make the flight with a failed vacuum pump, particularly at high altitude in night conditions.” The report noted that the 421’s master minimum equipment list permits operation of the airplane with one vacuum pump inoperative only during the day and under visual flight rules.
Aerospatiale AS355. Substantial damage. One fatality.
Witnesses said that it was dark and “extremely foggy” when the pilot departed from Erwinna, Pennsylvania, U.S., the morning of Oct. 17, 2012, for a positioning flight to Philadelphia’s Wings Field.
Data recovered from a handheld GPS receiver aboard the helicopter indicated that it stayed low and entered a right turn after lifting off from the helipad. The turn rate gradually increased, and the helicopter descended into trees and terrain.
Noting that the AS355 was not equipped for instrument flight, the NTSB report said that the probable cause of the accident was “the pilot’s decision to depart under visual flight rules in dark night instrument meteorological conditions, which resulted in subsequent spatial disorientation.”
Half Fuel, Half Water
Aerospatiale Alouette. Substantial damage. No injuries.
Shortly after the helicopter departed from Libode, South Africa, to provide support for the construction of a power line the afternoon of Nov. 22, 2012, the engine lost power. “The pilot elected to execute a forced landing on a ridge,” the South African CAA report said. “The left wheel caught the contour and lifted the tail boom before it impacted with the ground. … The tail rotor broke off, and the helicopter rolled over.”
The pilot, who was not hurt in the crash, told investigators that he had conducted a thorough preflight inspection of the helicopter, which had been refueled five weeks previously and parked. The report noted that the pilot had not flown the helicopter during that time because of rainfall and a strike at the construction company.
A post-accident examination of the helicopter by the operator revealed a 50 percent water/fuel mixture in the fuel filter and the main fuel line; “minimal amounts” of water were found in the fuel tank, however, the report said.
“Given the quantity of water present and where it was found, there can be no doubt that the fuel supplied and used for refueling of the helicopter [five weeks earlier] was contaminated with water that directly contributed to the helicopter suffering an engine failure,” the report said.
Robinson R22 Beta II. Substantial damage. One fatality.
Witnesses said that the R22 was cruising about 500 ft over Apollo Beach, Florida, U.S., the afternoon of Nov. 30, 2012, when they heard a bang and saw both main rotor blades separate. The helicopter rolled right and descended in a nose-down attitude into the bay.
One of the main rotor blades was not recovered. Examination of the recovered rotor blade, the rotor hub and the teetering stops showed signs of mast bumping. “The observed mast bumping could have resulted from large, abrupt flight control inputs or from a mechanical failure of the unrecovered main rotor blade,” the NTSB report said.