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.
Nonstandard Departure Clearance
Airbus A300-605R, Boeing Vertol CH-47D. No damage. No injuries.
A tower controller’s use of nonstandard air traffic control (ATC) communications phraseology in a departure clearance and an A300 flight crew’s misunderstanding of an initial altitude assignment resulted in the freighter coming within close proximity of a Chinook helicopter that was orbiting above the military airfield, according to the report by the U.K. Air Accidents Investigation Branch (AAIB).
The incident occurred in visual meteorological conditions (VMC) at RAF Brize Norton Aerodrome in Oxfordshire, England, the afternoon of Nov. 18, 2011. Visibility was greater than 10 km (6 mi), and surface winds were from 180 degrees at 8 kt. There were a few clouds at 1,800 ft and a broken ceiling at 12,000 ft.
The A300 was of Turkish registration. The crew, comprising two pilots and a loadmaster, had flown the aircraft to Brize Norton that morning and were preparing to return to Istanbul with a load of cargo. “It was the commander’s first rotation through Brize Norton, but the copilot had been there a number of times,” the report said. “Both were Turkish nationals with a good working knowledge of English.”
The copilot, the pilot monitoring, was handling ATC communications. The ground controller issued taxi instructions to Runway 26 and a departure clearance specifying a standard instrument departure procedure that included an initial climb to Flight Level (FL) 080 (approximately 8,000 ft).
After the copilot read back the clearance, the flight crew briefed the departure procedure and entered it into the flight management system, with 8,000 ft selected as the initial target altitude. “The commander intended to use the autopilot engaged with the ‘Profile Mode’ to be selected after takeoff,” the report said. “In this mode, the autopilot follows the horizontal and vertical profile of the departure and levels off at the target altitude.”
The pilots decided that there was sufficient runway available to begin the takeoff from the Echo intersection, and the copilot made the request. The ground controller instructed the crew to taxi to Echo and to establish radio communication with the tower controller.
“Having changed frequency, the next information the crew were expecting to be passed was either to line up at Echo or to continue the taxi to holding point Foxtrot, from which the full length of the runway is available for takeoff,” the report said.
On initial contact, the tower controller issued an altimeter setting and told the crew that they would have a “climb-out restriction, two thousand two hundred feet.”
The pilots misunderstood the instruction. “The crew, who were expecting taxiway- and runway-related information, interpreted the [‘two thousand two hundred feet’] to be the runway length reduction when entering the runway from holding point Echo,” the report said. “Although both pilots were familiar with the term ‘climb-out restriction,’ they did not register the information as an altitude and therefore did not read back the phrase.”
The copilot read back only the altimeter setting and repeated the request for takeoff from the Echo intersection. The tower controller asked the A300 copilot to confirm the climb-out restriction. The copilot replied, “Yes, good, copied, thank you.”
The controller said, “I need you to say back, climb-out restriction two thousand two hundred feet.”
“Yeah, two thousand two hundred feet copied,” the copilot said.
The report said that the copilot likely still related this to runway length. The climb restriction actually had been issued to provide vertical separation from the Chinook, which was on an instrument training flight with four crewmembers aboard.
The controller did not persist in obtaining a full readback of the instruction. He told the crew to line up and wait on the runway at the Echo intersection. The crew then was cleared for takeoff from Runway 26.
The A300 was on initial climb when the crew was told to contact the departure controller. At the time, the helicopter was at 3,500 ft and entering a holding pattern at a nondirectional beacon near the departure path of Runway 26.
The departure controller, expecting the freighter to level at 2,200 ft, advised the crew that “traffic” (the Chinook) was at their 1 o’clock position, 1,000 ft above and on a similar heading. The copilot replied that they had the helicopter in sight.
The A300 was climbing through 2,200 ft at about 3,000 fpm when the controller asked the crew to report their “passing [current] altitude.” The copilot said, “Now above two thousand nine hundred.” The controller told the crew to immediately stop the climb. The copilot replied they were climbing through 3,400 ft in compliance with a traffic-alert and collision avoidance system (TCAS) resolution advisory.
“The returns from the two aircraft were seen to merge on the ATC radar display,” the report said. “According to TCAS data from the A300, the minimum lateral separation between the A300 and the Chinook was 0.11 nm [0.20 km] and the minimum vertical separation was 496 ft.”
The Chinook was in a left turn when the crew saw the A300 pass overhead. The crew later filed an Airprox report.
Although the freighter crew was found to be familiar with the term “climb-out restriction,” the phraseology does not appear in the civilian or military sections of CAP 413, Radiotelephony Manual, the report said. “It does appear in other military documents, but these are not available to civilian pilots.”
According to CAP 413, the proper phraseology for the altitude restriction would have been: “Climb to altitude two thousand two hundred feet.”
Moreover, the document requires flight crews to state the altitude through which they are passing and their assigned altitude on initial contact with departure control. The A300 crew did not do this. If they had, it “would have immediately alerted the controller to the fact that the aircraft would not level at 2,200 ft,” the report said.
After the incident, Brize Norton authorities revised their controllers’ handbook to eliminate the term “climb-out restriction” and to require departure controllers to remind flight crews of their altitude assignments if they are not stated on initial contact.
Cessna Citation 550B. Destroyed. Two fatalities.
The flight crew departed from Prague, Czech Republic, the night of Feb. 14, 2010, for a positioning flight to Karlskrona, Sweden. The pilot-in-command (PIC), 27, had about 1,700 flight hours and had been employed by the aircraft-management company in 2009. The copilot, 32, had about 1,600 flight hours and had been with the company since 2005.
While climbing to the assigned cruise altitude, FL 330, the PIC mentioned that she had not flown at night for a long time. The copilot, who was hand flying the airplane, said, “Have you already experienced a roll during night?”
During the ensuing conversation, the pilots “no longer paid appropriate attention to airmanship and engaged in something neither they nor the airplane could handle,” said the English translation of the accident report published in September by the German Federal Bureau of Aircraft Accident Investigation (BFU).
“At no time during the conversation did the PIC exercise her leadership role,” the report said. “The impression arose [from the cockpit voice recording] that the PIC encouraged the intention of the copilot [to roll the aircraft].”
Neither pilot had received training in aerobatics, and the airplane was not certified for aerobatic flight. The report said, however, that the recorded conversation also indicated that both pilots “had flown aerobatics in the past with other airplanes of the company.”
The copilot leveled the Citation at FL 270 and attempted to roll it. “The nose moved upward until a pitch angle of about 14 degrees was reached [and] the airplane began to roll about its longitudinal axis to the right,” the report said. “Within 4 seconds the airplane reached the inverted flight attitude, and in another 4 seconds it rolled another 90 degrees. … During the roll, the pitch angle decreased to almost –85 degrees, which is almost a vertical nosedive. The computed airspeed increased significantly.”
The airplane struck terrain near Reinhardtsdorft-Schöna, Germany, just north of the border of the Czech Republic. BFU concluded that the pilots had lost spatial orientation and control of the Citation while attempting to roll the airplane on a moonless night that provided no visual references for the unauthorized maneuver.
Seat Detaches on Overrun
Gulfstream G150. Substantial damage. One serious injury, three minor injuries.
The G150 was en route from Stuart, Florida, U.S., to Key West, Florida, the night of Oct. 31, 2011. The destination airport had one runway and was reporting surface winds from 360 degrees at 12 kt, gusting to 17 kt, 10 mi (16 km) visibility and broken ceilings at 1,000 ft and 1,400 ft.
ATC cleared the flight crew to conduct a visual approach to Runway 27, which was 4,801 ft (1,463 m) long and 100 ft (30 m) wide. “The flight crew lost sight of the runway due to some low stratus clouds and discontinued the approach,” said the report by the U.S. National Transportation Safety Board (NTSB). “The controller then instructed them to overfly the airport and enter a right downwind leg for Runway 27, which they did.
“During the second approach, they again temporarily lost sight of the runway due to clouds while turning from the base [leg] to the final leg; however, they were able to visually reacquire the runway on final approach.”
According to the report, the PIC recognized that they were going to land long but continued the approach. The G150 touched down on the main landing gear at 120 kt, the reference landing speed, and 1,650 ft (503 m) from the approach threshold. When the nose landing gear touched down 2.4 seconds later, there was about 2,680 ft (817 m) of runway remaining.
“Landing distance data revealed that the airplane required about 2,551 ft [778 m] to stop at its given weight in the given weather conditions,” the report said. “With a runway distance of 2,680 ft remaining, the airplane could have stopped or gone around uneventfully with appropriate use of all deceleration devices.”
However, the ground spoilers did not deploy on touchdown. Investigators found that the spoilers had been armed for the landing and were not able to determine conclusively why they did not deploy.
“The landing procedure stated to activate the thrust reversers after nosewheel touchdown and then apply the [wheel] brakes, as necessary,” the report said. “However, the PIC only applied the brakes. Further, no callouts were made to verify ground spoiler or reverse thrust deployment.”
The report said that likely due of the absence of deceleration provided by spoiler deployment, both pilots perceived incorrectly that the wheel brakes were not working properly. “The procedure for a (perceived) failed brake system would have been to activate the emergency brake, which neither pilot did.”
The PIC applied takeoff power and announced that he was initiating a go-around, but the second-in-command said that it was too late to go around. The PIC returned the throttles to idle and applied reverse thrust. “The PIC’s delayed decision to stop or go around resulted in about a 22-second delay in thrust reverser activation, which resulted in the runway overrun,” the report said.
One of the passengers was seriously injured when his seat detached as the airplane traveled over a ditch, struck a gravel embankment, crossed a service road and came to a stop at the edge of a pond 816 ft (249 m) from the runway.
Investigators determined that maintenance personnel had not installed the seat properly. It was an aft-facing seat that had been installed in a forward-facing position, and the shear plungers in the frame of the seat had not been lowered into the seat track. “The improper installation most likely resulted in the passenger’s seat separating from the seat track and exacerbating his injuries,” the report said.
Fuel, Hydraulic Leaks on Takeoff
Cessna Citation 560XL. Minor damage. No injuries.
Shortly after the flight crew retracted the flaps on takeoff from Nantucket, Massachusetts, U.S., the afternoon of Oct. 29, 2012, the tower controller advised that fuel was pouring from the left wing. “The crew also noted hydraulic and stabilizer annunciator lights and a gear unlocked indication,” the NTSB report said.
As the crew returned to the airport, they felt a slight airframe vibration and noticed that the fuel quantity in the left wing tank was decreasing rapidly. “The flight remained in the traffic pattern and returned to [the airport] for an uneventful landing with a fuel imbalance of about 1,000 lb [454 kg],” the report said.
Investigators determined that a new left main landing gear trunnion had been installed six weeks earlier and that maintenance personnel had not secured the aft pivot pin correctly. This resulted in separation of the aft portion of the trunnion from its fitting. “The end of the aft trunnion punctured the interior of the gear well, resulting in damage to surrounding structure and damage to the fuel cell and hydraulic line,” the report said.
Intruders Force Go-Around
Cessna 208B. Destroyed. One fatality, one serious injury.
The flight crew was conducting an unscheduled cargo flight to a gravel airstrip at 6,950 ft in Bilogai, Indonesia, the morning of Nov. 26, 2011. A curved approach was required due to hills near the runway.
The Grand Caravan was at 94 kt and just about to touch down when the crew saw local villagers walking along the right side of the 590-m (1,936-ft) runway. The crew initiated a go-around, and the aircraft entered a left climbing turn in a nose-high attitude. The Caravan then stalled and crashed in a corn field, killing the copilot and seriously injuring the pilot.
In its report, the Indonesian National Transportation Safety Committee (NTSC) noted that the airstrip is surrounded by agricultural fields and that farm workers often cross the runway to gain access to them. As a result of the accident, NTSC recommended that the runway be fenced to prevent intruders or that a warning system be installed to alert people to aircraft arrivals and departures.
‘Very Loud Noise’ on Takeoff
Let L-410 Turbolet. Substantial damage. No injuries.
The aircraft was lifting off with 10 passengers and two pilots from the runway at Ronaldsway Airport on the Isle of Man the afternoon of Nov. 5, 2012, when the flight crew heard a very loud noise.
“Suspecting an engine failure, the commander closed the throttles and landed ahead on the remaining runway,” the AAIB report said. The noise reduced substantially at the low power setting, and the crew taxied the Turbolet to a parking area and shut down the engines.
ATC discontinued operations on the runway but re-opened it after an inspection revealed no debris.
“After the incident, [the commander] commented that the event was unlike any he had experienced previously while flying or during training,” the report said. “In particular, he remarked on the very high level of noise and the absence of yaw [typical of an engine failure].” The copilot described the noise as “terrible.”
The left Walter M601E engine showed no external evidence of damage, but a tear-down inspection revealed that a balance plug on the centrifugal compressor disc had broken and separated from the disc.
“Balance plugs are used to balance the compressor disc and are screwed into the disc beneath the compressor blade roots,” the report said. “Following an investigation by the engine manufacturer, it was concluded that the broken balance plug had failed due to a fatigue crack. … The damage to the engine was contained within the engine casing and was insufficient to cause a significant loss of power.”
Salt Causes Compressor Stalls
Lockheed WP-3D Orion. No damage. No injuries.
The Orion, operated by the U.S. National Oceanic and Atmospheric Administration, was orbiting at 3,000 ft over the Atlantic Ocean in night instrument meteorological conditions (IMC) on Nov. 9, 2007, when compressor stalls and tailpipe fires occurred in three of the four engines.
The incident occurred 540 nm (1,000 km) east of St. John’s, Newfoundland, Canada, according to a report published by NTSB in May. The no. 3 engine malfunctioned first, followed moments later by the no. 4 and no. 1 engines. The aircraft commander (AC) told the flight engineer (FE) to shut down the no. 3 and no. 4 engines, apparently due to fire warnings for those engines.
The AC and FE noticed a power loss and an increase in turbine inlet temperature in the no. 1 engine, but there was no fire warning. “The AC directed the FE to pull back power on the no. 1 engine,” the report said. “Believing that he heard the order to shut down the no. 1 engine, the FE pulled the emergency shutdown handle for the no. 1 engine.
“While operating single-engine at 800 feet and 140 knots, the AC called for the immediate restart of the no. 1 engine. With the successful restart of the no. 1 engine, the airplane began a slow climb on two engines.” The crew subsequently was able to restart the other two engines and return to St. John’s for an uneventful landing.
An examination of the Orion revealed significant buildups of salt on all the engine intakes and first-stage compressors, as well as on the fuselage and windows. “After the salt was rinsed away with water, the engine efficiencies improved greatly, and no other anomalies were noted,” the report said.
Flight Displays Go Blank
Jetstream 41. Minor damage. No injuries.
About one hour into a flight with 12 passengers and three crewmembers from Southampton, England, to Aberdeen, Scotland, the morning of July 18, 2012, the Jetstream entered IMC, icing conditions and light turbulence at FL 220. Twenty minutes later, the attitude director indicator display in the commander’s electronic flight instrument system (EFIS) went blank.
The commander, the pilot monitoring, re-engaged the autopilot and conducted the “Symbol Generator Failure” checklist, which did not remedy the situation. Shortly thereafter, the other three EFIS screens went blank.
“The commander took control and flew the aircraft with reference to the main altimeter and standby instruments,” the report said. The crew declared an urgency and diverted the flight to Newcastle. The EFIS displays began to return to normal after the aircraft descended into VMC. The Jetstream subsequently was landed at Newcastle without further incident.
Investigators found that an electrostatic transient absorber (transzorb) in the left windshield heating system had failed, as designed, when it was exposed to a high-voltage static charge that had accumulated on the windshield either during the incident flight or previously. However, the failed transzorb had retained a residual charge and thus had not protected the avionics systems, as it was designed to do.
The transzorbs had reached two-thirds of their service life when the left inboard unit failed. After they were replaced, the EFIS equipment and the windshield heating system functioned normally. “The aircraft was subsequently returned to service, and no further defects regarding the EFIS system were reported,” the report said.