TSB critices Transport Canada on slow implementation of safety recommendation

April 11, 2011

A TSB investiation into a cabin smoke and passenger evacuation incident revealed that Transport Canada had not yet implemented an actual regulatory change after accepting a safety recommendation dated December 2007. The recommendation called for passenger safety briefings to include clear direction to leave all carry-on baggage behind during an evacuation.

On March 23, 2010 an Air Canada Airbus A320-211 (registration C-FTJO), operating as flight AC433, departed Montréal/Pierre Elliot Trudeau International Airport, Québec, for Toronto/Lester B. Pearson International Airport, Ontario, with 98 passengers and 6 crew members on board.
In cruise, 1 of the 3 hydraulic systems failed. The flight continued toward destination where the flight made an uneventful landing. While stopped on the runway awaiting a tow, smoke entered the cabin and an evacuation was ordered. Two crew members and 2 passengers received minor injuries during the evacuation.

The TSB concluded that:

  1. A leak from the number 1 yaw damper caused fluid to be ingested into the auxiliary power unit and sent through the air conditioning system, resulting in smoke entering the cabin.
  2. When the crew ordered the evacuation as a result of the smoke, several persons received minor injuries while exiting the aircraft via the emergency slides.

It appeared that many passengers deplaned with their carry-on luggage. It could not be determined whether this was due to the fact that they were not aware of the instructions given by the flight attendants and included in the safety card, or if they were aware, but chose to disregard them. Passengers would have been more aware of this restriction if information was included during the pre-takeoff and pre-landing passenger briefings, as per TSB recommendation A07-07.

The few injuries that did occur may have been aggravated by the fact that the slides were wet from the rain, and the resultant speed of the exiting persons was higher than normal. While the baggage did cause some minor injuries and delays at the bottom of the slides, it did not appreciably increase the evacuation time. Were this a higher level of threat or emergency, however, even a slight delay could have resulted in more serious consequences.

Transport Canada agreed with the Board’s recommendation (A07-07) that called for passenger safety briefings to include clear direction to leave all carry-on baggage behind during an evacuation. However, to date, no regulatory change has been implemented. Due to the extensive delay between TC’s acceptance of this recommendation and the implementation of actual regulatory change, identified safety dificiencies continue to persist.

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NTSB progress report on United Airlines 497 runway excursion at New Orleans

April 8, 2011

The National Transportation Safety Board continues to make progress in its investigation of United Airlines flight 497, which returned to the airport on April 4, 2011, in New Orleans, shortly after take-off due to automated warnings of smoke in the equipment bay. The airplane’s nose wheel exited the side of runway 19 upon completing the landing roll and an emergency evacuation was conducted.

The NTSB team, comprised of 3 NTSB investigators and representatives from the designated parties and advisors, arrived on scene April 4 to document and examine the aircraft and retrieve the data and voice recorders. Two other NTSB investigators, specializing in operational factors and maintenance factors, traveled to various locations to review pertinent documentation and records and conduct interviews.

After documenting the condition of the equipment in the electronics bay, investigators applied limited electrical power to various systems on the airplane. At this time, the preliminary examination has not revealed any signs of burning, indications of smoke or other anomalous system findings.

The NTSB operations group completed interviews of the flight crew yesterday. The crew indicated that, at about 4000 feet, the airplane’s electronic centralized aircraft monitoring (ECAM) system provided an autothrottle-related message, then an avionics smoke warning message, accompanied by instructions to land. Despite receiving this message, neither crew member recalled smelling smoke or fumes during the flight.

The captain indicated that he used the electronic checklist for the avionics system smoke warning indication, which included shutting down some of the airplane’s electrical system. The crew reported that the first officer’s display screens went blank, the ECAM messages disappeared, the cockpit to cabin intercom stopped functioning, and the air-driven emergency generator deployed. The captain said that he took control of the airplane at this point and managed the radios while the first officer opened the cockpit door to advise the flight attendants of the emergency and their return to New Orleans airport.

The crew also noted to investigators that they requested runway 10 for landing, but were told the runway was not available due to the presence of construction vehicles. The captain said that he was able to use the airspeed, altimeter, and attitude information on his primary flight display during the return to the airport, and that he ordered an evacuation after landing.

As previously reported, the airplane’s forward right slide did not properly inflate during the emergency evacuation. After examining the evacuation slides, investigators found that the aspirator for the forward right-hand slide was partially blocked. The aspirator component is the mechanism for inflating the slide during an emergency evacuation. Investigators have retained the slide for further evaluation.

Preliminary reports provided to investigators suggest that the flight attendants did not smell or see smoke in the cabin, but observed the cabin lights turn off and the intercom system cease to function during the flight. Interviews of the cabin crew will be conducted after the investigators complete their on-scene work to more thoroughly document the cabin crew’s observations and communications throughout the flight and emergency evacuation.

The cockpit voice recorder (CVR) and flight data recorder (FDR) arrived at NTSB headquarters in Washington, D.C. on April 5 and were successfully downloaded. The CVR is of good quality and captured approximately 7 minutes and 30 seconds of the incident flight. The FDR contained in excess of 25 hours of data and captured approximately 18 minutes of data relevant to the incident flight. Both the CVR and FDR stopped recording data prior to landing.

Investigators will remain on scene to complete their evaluation of the airplane and documentation of other factors in the incident.


NTSB investigating near midair collision over Minneapolis involving A320 and Beech 99 cargo aircraft

September 23, 2010

The National Transportation Safety Board is investigating a near midair collision between a commercial jetliner and a small cargo aircraft that came within an estimated 50 to 100 feet of colliding near the Minneapolis-St. Paul Airport (MSP).

On September 16, 2010, about 06:49 a.m. CDT, US Airways flight AWE 1848, an Airbus A320, was cleared for takeoff on runway 30R en route to Philadelphia, Pennsylvania, carrying five crewmembers and 90 passengers.

At the same time, Bemidji Aviation Services flight BMJ46, a Beech 99 cargo flight with only the pilot aboard, was cleared for takeoff on runway 30L en route to La Crosse, Wisconsin. Weather conditions at the time were reported as a 900-foot ceiling and 10 miles visibility below the clouds.

Immediately after departure, the tower instructed the US Airways crew to turn left and head west, causing the flight to cross paths with the cargo aircraft approximately one-half mile past the end of runway 30L. Neither pilot saw the other aircraft because they were in the clouds, although the captain of the US Airways flight reported hearing the Beech 99 pass nearby. Estimates based on recorded radar data indicate that the two aircraft had 50 to 100 feet of vertical separation as they passed each other approximately 1500 feet above the ground.

The US Airways aircraft was equipped with a Traffic Alert and Collision Avoidance System (TCAS) that issued climb instructions to the crew to avert collision. The Beech 99 was not equipped with TCAS and the pilot was unaware of the proximity of the Airbus. There were no reports of damage or injuries as a result of the incident.

NTSB and FAA investigators conducted a preliminary investigation at the Minneapolis airport traffic control tower on September 18th and 19th and are continuing to review the circumstances of this incident.

According to ACARS data, Flight AWE1848 was carried out by A320 N122US.


Report: blocked AOA sensors caused loss of control during A320 check flight

September 17, 2010

The French Bureau d’Enquêtes et d’Analyses (BEA) issued their final report of the investigation into the cause of a fatal accident involving an Airbus A320 in November 2008, citing amongst others blocked AOA sensors.

Airbus A320 D-AXLA had been leased by XL Airways Germany since May 2006. The airplane was due to be returned to its owner, Air New Zealand, on December 1, 2008. The Airbus was ferried to Perpignan (PGF), France where it underwent maintenance at EAS Industries. It was also repainted in full Air New Zealand livery. The leasing agreement specified a programme of in-flight checks to ensure the airplane was fit for purpose.

The programme of planned checks could not be performed in general air traffic, so the flight was shortened. In level flight at FL320, angle of attack sensors 1 and 2 stopped moving and their positions did not change until the end of the flight. After about an hour of flight, the aeroplane returned to the departure aerodrome airspace and the crew was cleared to carry out an ILS procedure to runway 33, followed by a go around and a departure towards Frankfurt/Main (Germany). Shortly before overflying the initial approach fix, the crew carried out the check on the angle of attack protections in normal law. They lost control of the aeroplane, which crashed into the sea killing all seven on board.

BEA concluded that the accident was caused by the loss of control of the aeroplane by the crew following the improvised demonstration of the functioning of the angle of attack protections, while the blockage of the angle of attack sensors made it impossible for these protections to trigger.
The crew was not aware of the blockage of the angle of attack sensors. They did not take into account the speeds mentioned in the programme of checks available to them and consequently did not stop the demonstration before the stall.

ˆˆThe following factors contributed to the accident:

  • The decision to carry out the demonstration at a low height;
  • The crew’s management, during the thrust increase, of the strong increase in the longitudinal pitch, the crew not having identified the pitch-up stop position of the horizontal stabiliser nor acted on the trim wheel to correct it, nor reduced engine thrust;
  • The crew having to manage the conduct of the flight, follow the programme of in-flight checks, adapted during the flight, and the preparation of the following stage, which greatly increased the work load and led the crew to improvise according to the constraints encountered;
  • The decision to use a flight programme developed for crews trained for test flights, which led the crew to undertake checks without knowing their aim;
  • The absence of a regulatory framework in relation to non-revenue flights in the areas of air traffic management, of operations and of operational aspects;
  • The absence of consistency in the rinsing task in the aeroplane cleaning procedure, and in particular the absence of protection of the AOA sensors, during rinsing with water of the aeroplane three days before the flight. This led to the blockage of the AOA sensors through freezing of the water that was able to penetrate inside the sensor bodies.

The following factors also probably contributed to the accident

  • Inadequate coordination between an atypical team composed of three airline pilots in the cockpit;
  • The fatigue that may have reduced the crew’s awareness of the various items of information relating to the state of the systems.

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