Live camera views on an A380 as shown on the primary flight displays
(PFD) or on the system display (SD). This camera system does not display wingtips or wingtip paths yet (photo: NTSB).

The U.S. NTSB recommended that the Federal Aviation Administration (FAA) require that large airplanes be equipped with an anti-ground collision aid, such as an on-board external-mounted camera system, to provide pilots a clear view of the plane’s wingtips while taxiing to ensure clearance from other aircraft, vehicles and obstacles.

On large airplanes (such as the Boeing 747, 757, 767, and 777; the Airbus A380; and the McDonnell Douglas MD-10 and MD-11), the pilot cannot see the airplane’s wingtips from the cockpit unless the pilot opens the cockpit window and extends his or her head out of the window, which is often impractical.

The NTSB said that the anti-collision aids should be installed on newly manufactured and certificated airplanes and that existing large airplanes should be retrofitted with the equipment.

The recommendations follow three recent ground collision accidents (all currently under investigation) in which large airplanes collided with another aircraft while taxiing:

May 30, 2012: The right wingtip of an EVA Air Boeing 747-400 struck the rudder and vertical stabilizer of an American Eagle Embraer 135 while taxiing at Chicago’s O’Hare International Airport (Preliminary Report).

July 14, 2011: A Delta Air Lines Boeing 767 was taxiing for departure when its left winglet struck the horizontal stabilizer of an Atlantic Southeast Airlines Bombardier CRJ900 (Preliminary Report).

April 11, 2011: During a taxi for departure, the left wingtip of an Air France A380 struck the horizontal stabilizer and rudder of a Comair Bombardier CRJ701 (Preliminary Report).

The NTSB made the same recommendation to the European Aviation Safety Agency, which sets standards for aircraft manufacturers in Europe.

More information:

• NTSB Safety Recommendation letter

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Boeing 767 hard landing damage prompted AAIB to issue two safety recommendations on  Flight Data Monitoring (photo: AAIB)

The U.K. Civil Aviation Authority (CAA) issued a Safety Notice, recommending that all U.K. operators ensure that they are analysing their Flight Data Monitoring (FDM) data relating to landings not only by airport, but also by runway.

The U.K. Air Accidents Investigation Branch (AAIB) recently investigated an incident  involving a Boeing 767 hard landing at Bristol International Airport and have since made two specific recommendations, 2012-014 and 2012-015, with regard to FDM and data analysis.

The incident happened on 3 October 2010 when a Boeing 767 landed heavily on runway 09 at Bristol Airport and resulted in a crease over the fuselage crown. Upon investigation of the incident it was discovered through historic data that the operator had an unusually high rate of hard landings at runway 09 versus the other runway at Bristol Airport. Prior to this incident the operator had carried out their analysis on an airport by airport basis, the results of which did not indicate an unusually high rate at Bristol. The operator had not analysed and aggregated their heavy landing data for individual runways as part of their routine analysis of FDM data, thus the high rate at runway 09 was not identified. In addition to this it was discovered that the operator had not set a threshold limit, above which action should be taken, for the rate of hard landings.

In light of this incident the CAA recommend that all U.K. operators ensure that they are analysing their FDM data relating to landings not only by airport, but also by runway. This will ensure that any adverse trends specific to one runway are more readily identifiable. When routinely monitoring data trends, it is important to be able to identify significant changes or deviations from what is deemed to be acceptable. The CAA recommend that operators should establish trigger levels and maximum rates beyond which action should be taken to reduce the occurrence of issues such as individually heavy landings or abnormally frequent firm landings. This should be accomplished in conjunction with aircraft manufacturers and take into consideration both Airworthiness (structural) and Operational (pilot proficiency) perspectives.

More information:

• CAA Safety Notice SN-2012/014: The Proactive Use of Flight Data
• AAIB incident investigation report Boeing 767 G-OOBK

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ASN File photo of an ATR-72 PW127 engine in flight

The Italian ANSV, while investigating an ATR-72 engine failure incident, issued four safety recommendations to EASA and Transport Canada. The investigators had found two recent similar incidents in Hungary and Denmark.

All three incidents occurred in the initial climb phase and were all due to the initial distress of a Power Turbine 1st stage rotor blade causing subsequent damages and heavy unbalance of the whole PT assembly, further unbalance of the low pressure (LP) rotor through No. 6 & 7 bearing housing, and final oil leakage due to breaking of No. 6 & 7 bearing compartment retaining bolts and distress of the radial transfer tubes. Fire was then originated by such a leakage in presence of hot parts.

In all these serious incidents distress of the PT1 rotor blade was due to a crack propagated from an internal casting defect (shrinkage porosity) in the vicinity of the blade core pocket.

The ANSV recommends:

• EASA: to review the emergency procedures on ATR aircraft in order to ensure efficient removal of persisting smoke and appropriate cockpit/passenger cabin ventilation;
• Transport Canada: to consider the need to early withdraw from service the PT1 rotor blades manufactured before the introduction of NDT improvement or, alternatively, to urgently introduce a one shot X-Ray inspection on all those blades having accumulated a number of cycles beyond a limit to be established (e.g. 2000), specifically focused on the pocket area to exclude the presence of a fatigue crack.
• Transport Canada:  taking into account the high volume of PT1 rotor blade production, to consider the opportunity to introduce in production, at least as a temporary measure, an additional Computed Tomography check on a representative sample of blades in order to gain confidence on the effective improvement achieved through the review of the X-Ray methodology implemented in 2008.
• EASA:  to consider the need to harmonize the procedures, or to review the existing documentation as necessary, in order to establish in all cases a time limit within which to make effective in the AFM owned by operators the amendments approved by EASA.

More information:

• ANSV safety recommendation (PDF)
• 17 June 2011 TAROM ATR-42 incident
• 13 September 2011 Cimber Sterling ATR-72 incident
• 3 October 2011 Air Dolomiti ATR-72 incident

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File photo of an American Airlines Boeing 767-300ER (photo: Marcin Jagodzinski, CC-by-nc)

The  U.S. National Transportation Safety Board (NTSB) issued one safety recommendation to prevent possible fires on General Electric CF6-80C2 engines. The recommendation was made in the course of the investigation into the cause of an incident in February 2012.

On February 8, 2012, American Airlines flight 837, a Boeing 767-300ER airplane, equipped with General Electric CF6-80C2B6 engines, experienced a fire in the right engine shortly after taking off from New-York-John F. Kennedy International Airport (JFK). The pilots stated that they shut down the engine and discharged both fire bottles into the engine’s nacelle before the fire warning was deactivated. An emergency was declared and a single-engine, overweight landing was performed at JFK without further incident.  There were no injuries to the 201 passengers, 9 flight attendants, and 3 pilots on board.

Investigation of the engine revealed that the two-part support bracket and spray shield of a fuel-oil heat exchanger was misassembled. This ultimatly caused a fuel leakage.

Although General Electric had already issued a Service Bulletin to deal with this issue, it was still not required for operators to accomplish the Service Bulletin’s actions. The NTSB now recommends the FAA to:

Issue an airworthiness directive to require the incorporation of General Electric Aircraft Engines Service Bulletin 73-0242, “Fuel and Control – (73-00-00) – Spray Shields and Support Bracket – Improvement,” to prevent fires on CF6-80C2 engines due to misassembly of the two-piece support bracket and spray shield on the front of the integrated drive generator fuel-oil heat exchanger. (A-12-47)

More information:

• NTSB Safety Recommendation Letter A-12-47

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Wreckage of AF447 was found on the sea bed (photo: BEA)

After an investigation lasting over three years, the French Bureau d’Enquetes et d’Analyses (BEA) released the final report on the cause of the fatal accident involving Air France flight AF447.

On June 1, 2009, an Airbus A330-200 crashed into the Atlantic Ocean during a flight from Rio de Janeiro-Galeão International Airport, RJ (GIG), Brazil, to Paris-Charles de Gaulle Airport (CDG), France. All 216 passengers and 12 crew members were killed.

BEA issued a total of 41 safety recommendations in the wake of the accident, of which 24 were issued together with the final report.

As to the causes of the accidents, BEA concludes the following:
The obstruction of the Pitot probes by ice crystals during cruise was a phenomenon that was known but misunderstood by the aviation community at the time of the accident. From an operational perspective, the total loss of airspeed information that resulted from this was a failure that was classified in the safety model. After initial reactions that depend upon basic airmanship, it was expected that it would be rapidly diagnosed by pilots and managed where necessary by precautionary measures on the pitch attitude and the thrust, as indicated in the associated procedure.
The occurrence of the failure in the context of flight in cruise completely surprised the pilots of flight AF 447. The apparent difficulties with aeroplane handling at high altitude in turbulence led to excessive handling inputs in roll and a sharp nose-up input by the PF. The destabilisation that resulted from the climbing flight path and the evolution in the pitch attitude and vertical speed was added to the erroneous airspeed indications and ECAM messages, which did not help with the diagnosis.
The crew, progressively becoming de-structured, likely never understood that it was faced with a ‘simple’ loss of three sources of airspeed information.
In the minute that followed the autopilot disconnection, the failure of the attempts to understand the situation and the de-structuring of crew cooperation fed on each other until the total loss of cognitive control of the situation. The underlying behavioural hypotheses in classifying the loss of airspeed information as ‘major’ were not validated in the context of this accident. Confirmation of this classification thus supposes additional work on operational feedback that would enable improvements, where required, in crew training, the ergonomics of information supplied to them and the design of procedures.
The aeroplane went into a sustained stall, signalled by the stall warning and strong buffet. Despite these persistent symptoms, the crew never understood that they were stalling and consequently never applied a recovery manoeuvre. The combination of the ergonomics of the warning design, the conditions in which airline pilots are trained and exposed to stalls during their professional training and the process of recurrent training does not generate the expected behaviour in any acceptable reliable way.
In its current form, recognizing the stall warning, even associated with buffet, supposes that the crew accords a minimum level of ‘legitimacy’ to it. This then supposes sufficient previous experience of stalls, a minimum of cognitive availability and understanding of the situation, knowledge of the aeroplane (and its protection modes) and its flight physics. An examination of the current training for airline pilots does not, in general, provide convincing indications of the building and maintenance of the associated skills.
More generally, the double failure of the planned procedural responses shows the limits of the current safety model. When crew action is expected, it is always supposed that they will be capable of initial control of the flight path and of a rapid diagnosis that will allow them to identify the correct entry in the dictionary of procedures. A crew can be faced with an unexpected situation leading to a momentary but profound loss of comprehension. If, in this case, the supposed capacity for initial mastery and then diagnosis is lost, the safety model is then in ‘common failure mode’. During this event, the initial inability to master the flight path also made it impossible to understand the situation and to access the planned solution.
Thus, the accident resulted from the following succession of events:
- Temporary inconsistency between the airspeed measurements, likely following the obstruction of the Pitot probes by ice crystals that, in particular, caused the autopilot disconnection and the reconfiguration to alternate law;
- Inappropriate control inputs that destabilized the flight path;
- The lack of any link by the crew between the loss of indicated speeds called out and the appropriate procedure;
- The late identification by the PNF of the deviation from the flight path and the insufficient correction applied by the PF;
- The crew not identifying the approach to stall, their lack of immediate response and the exit from the flight envelope;
- The crew’s failure to diagnose the stall situation and consequently a lack of inputs that would have made it possible to recover from it.
These events can be explained by a combination of the following factors:
- The feedback mechanisms on the part of all those involved that made it impossible:
* To identify the repeated non-application of the loss of airspeed information procedure and to remedy this,
* To ensure that the risk model for crews in cruise included icing of the Pitot probes and its consequences;
- The absence of any training, at high altitude, in manual aeroplane handling and in the procedure for ‘Vol avec IAS douteuse’;
- Task-sharing that was weakened by:
* Incomprehension of the situation when the autopilot disconnection occurred,
* Poor management of the startle effect that generated a highly charged emotional factor for the two copilots;
- The lack of a clear display in the cockpit of the airspeed inconsistencies identified by the computers;
- The crew not taking into account the stall warning, which could have been due to:
* A failure to identify the aural warning, due to low exposure time in training to stall phenomena, stall warnings and buffet,
* The appearance at the beginning of the event of transient warnings that could be considered as spurious,
* The absence of any visual information to confirm the approach-to-stall after the loss of the limit speeds,
* The possible confusion with an overspeed situation in which buffet is also considered as a symptom,
* Flight Director indications that may led the crew to believe that their actions were appropriate, even though they were not,
* The difficulty in recognizing and understanding the implications of a reconfiguration in alternate law with no angle of attack protection.

 

More information:

• BEA AF447 documents and final report

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The ATR-42 as it came to rest near the runway at Lubbock, TX

The U.S. National Transportation Safety Board issued four additional safety recommendations in the wake of a non-fatal ATR-42 accident at Lubbock Airport, TX in 2009. The NTSB recommends to revise the stick pusher’s activation angle of attack (AOA) on ATR 42-series airplanes.

On January 27, 2009, an ATR 42-320 operating as Empire Airlines flight 8284, was on an instrument approach when it crashed short of the runway at Lubbock-Preston Smith International Airport, Texas. The captain sustained serious injuries, and the first officer sustained minor injuries. The airplane was substantially damaged.

The NTSB determined that the probable cause of  this accident was the flight crew’s failure to monitor and maintain a minimum safe airspeed while executing an instrument approach in icing conditions, which resulted in an aerodynamic
stall at low altitude.

A further review by the NTSB showed that current guidance emphasizes reducing the AOA as the primary means to stall prevention, and the stick pusher is intended to aid the pilot in that action. However, the NTSB is  concerned that, for in-service stick pusher-equipped transport-category airplanes, if the activation angle of the stick pusher is not reduced in icing conditions, its benefit in reducing the airplane’s AOA prior to stall and during recovery efforts is lost. The NTSB concludes that a lower stick pusher activation AOA would enhance safety in icing conditions and provide stall protection
before an uncommanded roll develops during stall.

Therefore, the NTSB recommends the FAA to:

1. Require that Avions de Transport Régional (ATR) 42-series airplanes operating in the United States incorporate a revised stick pusher activation angle of attack (AOA), such that the stick pusher activates before the stall AOA in the presence of airframe ice accretions.
2. Evaluate all  U.S.-certificated  transport-category airplanes  equipped with stick pushers  to ensure that the stick pusher  activates at an angle of attack that will provide adequate  stall  protection in the presence of  airframe  ice accretions.

And the NTSB recommends EASA to:

1. Require  Avions de Transport Régional (ATR) to revise the stick pusher’s activation  angle of attack (AOA)  on ATR 42-series airplanes  to ensure that the stick pusher activates  before the stall AOA in the presence of airframe ice accretions.
2. Evaluate all  European Aviation Safety Agency-certificated  transport-category airplanes equipped with stick pushers to ensure that the stick pusher activates at an  angle of  attack that will  provide adequate stall  protection in the presence of airframe ice accretions.

More information:

• ASN Accident Description
• NTSB Safety Recommendations A-12-24 and -25
• NTSB Safety Recommendations A-12-26 and -27

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Superjet 97004 departing Jakarta-Halim on it’s final flight

The Indonesian National Transportation Safety Committee (NTSC) issued five safety recommendations in the wake of the accident involving a Sukhoi Superjet in May 2012.

A Sukhoi Superjet 100 passenger plane was destroyed when it struck the side of a mountain during a demonstration flight over Indonesia. All 45 on board were killed.

An IFR flight plan had been filed for the demonstration flight out of Jakarta-Halim Perdana Kusuma Airport.

Although the investigation is still ongoing, the NTSC already issued five safety recommendations based on their findings so far:

The Indonesian Directorate General of Civil Aviation:
- To ensure that all aircraft used for a demonstration flight operated under IFR should be conducted with respect to a published minimum safe flight altitude.
- To ensure a copy of the crew and passenger manifest be available in the Ground handling and Operation Service office prior to flight.

The Sukhoi Civil Aircraft Company, Russian Federation
- To review the current procedures for the preparation and conduct of a demonstration flight and, if needed, introduce appropriate amendments.
- To arrange additional training for flight crews who will conduct demonstration flights, especially in mountainous regions.
- To ensure a copy of the crew and passenger manifest be available in the Ground handling and Operation Service office prior to flight.

More information:

• ASN Accident Description
• NTSC Safety Recommendation letter

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B757 in the snow at Jackson Hole, WY (photo: NTSB)

Mechanical defects that prevented the automatic deployment of speedbrakes and the captain’s failure to monitor and manually deploy them led to an overrun of a Boeing 757 off of a snowy runway at Jackson Hole Airport, WY (JAC). The incident was compounded by an anomaly with the thrust reversers, the NTSB reported.

On December 29, 2010, at about 11:38 a.m. MST, American Airlines flight 2253, a Boeing 757-200, ran off the departure end of runway 19 during light snow after landing at Wyoming’s Jackson Hole Airport (JAC). The airplane came to rest about 730 feet past the departure end of the runway in deep snow. None of the 179 passengers and six crewmembers were injured; the airplane sustained minor damage. The flight originated from Chicago-O’Hare Airport.

The NTSB investigation found that the pilots, both of whom had flown into JAC on numerous occasions, were familiar with the challenging wintertime landing conditions there and had made thorough preparations for the approach and landing during what they described as an otherwise uneventful flight from Chicago.

The approach to the runway was normal and the airplane touched down about 600 feet beyond the approach threshold. The speedbrakes, which disrupt the airflow over the wings and greatly increase the wheel braking effectiveness, did not automatically deploy as designed. The CVR transcript showed that the captain, acting as the monitoring pilot, failed to identify the non-deployment and erroneously stated “deployed” shortly after touchdown. Immediately after this, the first officer, who was the pilot flying, tried to deploy the thrust reversers; when they did not initially deploy, the captain took over the thrust reverser controls and they deployed about 18 seconds after touchdown. Subsequently, the airplane continued off the departure end of the runway, coming to a stop in deep snow off the end of the paved surface.

American Airlines training and procedures require the pilot monitoring (in this case, the captain) to observe and call out the position of the speedbrake lever after landing; if the speedbrakes do not deploy automatically, the captain is to manually deploy them. Although the pilots could have manually deployed the speedbrakes at any time during the landing roll, neither pilot recognized that the speedbrakes had not automatically deployed because they were both trying to resolve the thrust reverser issue.

The landing performance analysis showed that under similar runway conditions, even without thrust reverser deployment, the airplane would have stopped about 4500 feet down the 6300-foot runway had the speedbrakes been promptly deployed.

The investigation revealed that the speedbrakes did not automatically deploy because of a latent assembly defect in one of the speedbrakes mechanisms. In addition, the NTSB determined that the thrust reversers did not initially deploy because of a rare mechanical/hydraulic interaction that occurred in the thrust reverser system as a result of an unloading event at the precise instant that the first officer commanded their deployment immediately after touchdown.

As a result of the investigation, the NTSB made the following new safety recommendations to the Federal Aviation Administration (FAA):

1. Require all operators of existing speedbrake-equipped transport-category airplanes to develop and incorporate training to specifically address recognition of a situation in which the speedbrakes do not deploy as expected after landing.
2. Require all newly type-certificated 14 Code of Federal Regulations Part 25 airplanes to have a clearly distinguishable and intelligible alert that warns pilots when the speedbrakes have not deployed during the landing roll.
3. Require Boeing to establish guidance for pilots of all relevant airplanes to follow when an unintended thrust reverser lockout occurs and to provide that guidance to all operators of those airplanes.

More information:

NTSB report synopsis

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Flight US1209 flightpath; red dots indicate total lightning detected (source: NTSB)

The National Transportation Safety Board (NTSB) has recently investigated several accidents and incidents in which air carrier airplanes have encountered significant convective weather conditions in flight, resulting in turbulence-induced crew and passenger injuries, damage to airplanes from hail and lightning strikes, and associated flight diversions.  For example, on August 14, 2011, US  Airways  flight 1209, a Boeing 757 en route from Philadelphia, Pennsylvania, to Philipsburg, St. Maarten, was struck by lightning at approximately 16,000 feet. The crew reported smoke in the cockpit, declared an emergency, and diverted to Baltimore, Maryland, where the airplane landed without further incident. Because thunderstorms are, by definition, always accompanied by lightning, the presence of lightning is a strong indicator of potentially severe weather conditions, and its identification serves to locate areas that should be avoided by all aircraft. Pilots and air traffic controllers currently attempt to protect aircraft from such encounters by using both airborne and ground-based weather radar systems that detect significant precipitation, which is frequently associated with convective weather. The NTSB believes that in addition to the precipitation data provided by weather radars, real-time information provided by modern “total lightning” detection networks can further assist pilots and controllers in identifying specific areas where lightning exists, and, through observation of storm motion, may exist as aircraft proceed along their flightpaths. Therefore, the National Transportation Safety Board makes the following recommendations to the Federal Aviation Administration:

• Study the technical feasibility of presenting, through the use of the weather and radar processor system or other means, real-time total lightning data on controller displays at both air route traffic control centers and terminal radar approach control facilities, and, if feasible, incorporate real-time total lightning data on controller displays and in associated weather products for current and future display systems. (A-12-18)
• To the extent practicable, incorporate direct center weather service unit briefings on new weather-related air traffic control equipment and information services into controller training. (A-12-19)
• Incorporate real-time total lightning data into the products supplied to pilots through the flight information services – broadcast data link. (A-12-20)

More information:

• NTSB Safety Recommendations A-12-18 through -20

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Palermo (LICJ) VOR-Z RWY 07 approach chart

The Italian investigation board ANSV is recommending a review of certain approach charts of Italian airports. The investigation into an Airbus A319 landing accident at Palermo learned that the crew used charts that were not fully compliant with ICAO principles.

On September 24, 2010, Windjet Flight 243, an Airbus A319, impacted the ground 367 meters before the runway 07 threshold and, after hitting the runway 25 localizer antenna, slid for about 850 meters before stopping on the left side of the runway. The crew were flying the so called “VOR-Z RWY 07″ approach procedure which uses the  TVOR and DME at Palermo.

An examination of the charts used by the flight crew showed that the phrase “DME required” was not mentioned on their approach chart. ICAO Doc 8168 Aircraft Operations Vol. 2 - Construction of Visual and Instrument Flight Procedures (paragraph 9.5.2.2) states: “If additional navigation aids are required for the approach procedure, associated additional equipment requirements shall be specified on the plan view of the chart, but not in the title.”

The same omissions were noted on other charts.

ANSV thus recommends the Italian Civil Aviation Authority (ENAC) and the Italian Air Navigation Services company ENAV to review the charts and to add any equipment requirements on the chart’s map.

More information

• ASN Accident Description
• ANSV Safety Recommendation ANSV-3/1836-10/2/A/12 (PDF, in Italian)

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