Home » ASN News
Report: misinterpreted taxiway markings factor in attempted takeoff from taxiway, Amsterdam
25 May 2022

Report: misinterpreted taxiway markings factor in attempted takeoff from taxiway, Amsterdam

ATSB publishes final report on A330 that took off with pitot covers attached

The Australian Transport Safety Bureau (ATSB) has released the final report from its investigation into a serious incident where a Malaysia Airlines Airbus A330 with 229 on board took off from Brisbane Airport with no airspeed information.
Shortly after the aircraft arrived in Brisbane from Kuala Lumpur on 18 July 2018, a support engineer placed covers on the aircraft’s three pitot probes (airspeed sensors) to prevent them from being blocked by mud wasps, a known hazard at Brisbane Airport.
However, during the turnaround and before the aircraft departed for the return flight to Kuala Lumpur the covers were not removed. This was despite there being requirements for multiple walk-around checks by the aircraft captain, engineer and dispatch coordinator, all intended to identify unsafe conditions such as the fitment of pitot probe covers.
Consequently, the aircraft’s primary instrument displays showed red speed flags in place of airspeed indications from early in the take-off, and the flight crew did not respond in time for the take-off to be safely aborted.
Once airborne the flight crew climbed the aircraft to 11,000 ft where they performed troubleshooting and other procedures, including shutting down the aircraft’s air data systems. This activated a system installed on some Airbus aircraft called the back up speed scale (BUSS), which displayed a safe flight envelope for flight crew to maintain.
Using the BUSS and airspeed management procedures, and assisted by air traffic control, the flight crew brought the aircraft safely back to Brisbane.

On the night, several individuals from different organisations had separate, key roles in detecting aircraft damage or other unsafe conditions such as the fitment of pitot probe covers. However, these checks were omitted entirely or only partially completed, for a variety of reasons including inadequate communication and reduced diligence.
Malaysia Airlines had recently reintroduced flights to Brisbane, and although the wasp risk was identified, the use of pitot probe covers was not required or controlled. Shortly after the occurrence, the ATSB issued a safety advisory notice (SAN) to operators who fly to Brisbane Airport to consider the use of pitot probe covers and, where they are used, ensure there are rigorous processes for confirming they are removed before flight.
The ATSB also uncovered a range of deeper issues, including coordination among the involved organisations, that allowed front-line problems to emerge.
For flight crew, the occurrence also highlights the importance of vigilance, communications, and decision-making in adverse circumstances.
The ATSB found that surprise, uncertainty, time pressure, and ineffective communication between the two pilots during the take-off probably led to stress and high cognitive workload. This reduced their capacity to interpret the situation and make a decision early enough to safely reject the take-off.

In response, the ATSB has issued a safety advisory notice (SAN) advising manufacturers and operators of all large transport aircraft to consider what types of unreliable airspeed events can occur, how the information is presented to pilots, and what responses are the safest in different phases of the take-off and in a range of potential situations.
All of the relevant organisations have contributed to the large number of safety actions taken in response to the incident and the ATSB’s investigation. For example, Malaysia Airlines now requires the placement of a placard on the flight deck as a visual alert that pitot probe covers are in place, and has introduced improvements to its change and risk management processes.
Airbus, meanwhile, has implemented additional flight crew training standards about unreliable airspeed on take-off, added guidance to the flight crew techniques manual on the importance of airspeed monitoring on take-off, and has commenced a review of airspeed indications in A330 and other aircraft types.
The ground handling and engineering companies involved in the incident have also made system and process improvements, and the airport information provided to pilots has been amended.

Report: Global 6000 suffers wing tip strikes after encountering gusting winds

Report: Loss of control when entering IMC caused a fatal flight calibration Citation crash

Report: A320 copilot made rolling takeff on wrong runway at Sharjah

Report: Pilot induced oscillations caused B777 tailstrike on landing

TSB concerned about safety when runways are under construction

The Transportation Safety Board (TSB) Canada concluded an investigation into a series of 18 occurrences on runways under construction at certain airports in Quebec and Nunavut in Canada. The TSB is concerned about the way runway closures are communicated by NAV CANADA and by the adequacy of regulatory surveillance of airports undergoing construction activities.

The events examined in the investigation occurred when the width of the runway was reduced, rather than the length, to allow for construction work without closing the runway. The investigation found that issues such as the construction method chosen, the visual aids used during construction, and the way that airport construction information is communicated to pilots can lead to pilots not being able to identify the open portion of the runway. Some of these hazards result from the complexity of the regulations and the absence of clear standards for airport construction and for preparing and approving construction plans. The investigation also found that, if the airport construction planning process places too much emphasis on external economic pressures to avoid closing the runway, there is an increased risk that not enough emphasis will be placed on safety.

In the absence of both information on which method should be used for runway rehabilitation and standards and recommended practices, decisions in regards to operations during airport construction lie entirely with the airport operator. It was determined that construction operations plans were approved by Transport Canada (TC) using informal procedures, without assessing the risk that pilots might not be able to recognize or distinguish the closed portions of the runways, and without including control measures to mitigate this risk.

The investigation also found issues with the the safety management systems (SMS) in place at the airports under review. Despite that all these airports had an SMS, the investigation identified that they were not effective at proactively managing the risks associated with the reduction in the runway width. Information gathered during the investigation also showed that TC’s surveillance policies and procedures were not being followed consistently, and that some of the key oversight procedures were not fully understood by TC’s inspectors.

In light of this, the Board is concerned that if TC does not provide adequate surveillance of airports in Canada, the risk of an accident related to flight operations at airports increases, particularly when the airports are undergoing construction.

Also, when an operator plans to carry out construction activities at their airport, they must communicate the necessary information to pilots by having a Notice to Airmen (NOTAM) issued by NAV CANADA. Currently, NOTAMs in Canada are only published in text format and cannot include graphics, which can hinder the effective communication of information. Consequently, even though the pilots had all read the available NOTAMs related to the partial runway closures, their mental models were inaccurate and they were not able to recognize or distinguish which portions were closed.

The Board therefore recommends that NAV CANADA make available, in a timely manner, graphic depictions of closures and other significant changes related to aerodrome or runway operations to accompany the associated NOTAMs, so that the information communicated on these hazards is more easily understood.

Report: CG beyond rear limit causes controllability issues on Metroliner

A Swearingen Metro freighter aircraft’s pilot had to use forward pressure on the control column to maintain level flight after ground handlers estimated the weight of freight that was relocated into the aircraft’s nose by feel. This resulted in the aircraft’s centre of gravity falling outside of the rear limit, an Australian Transport Safety Bureau investigation into the occurrence details.

On 11 May 2020, the twin turboprop Metro 23 aircraft, operated by Toll Aviation, was being loaded for a scheduled freight service from Townsville to Brisbane via Rockhampton, in Queensland.
Prior to take-off from Townsville, the pilot completed a load and trim sheet based on a load plan provided by the ground handling team.
A load and trim sheet is used to calculate the total weight on board, and to ensure the distribution of that weight does not shift the aircraft’s centre of gravity beyond lateral and longitudinal limits, which is critical to ensure stable, controllable flight.
The pilot’s calculation indicated the distribution of freight throughout the aircraft’s six main zones was too heavily weighted to the rear.
To address this, the pilot and ground handlers agreed 126 kg of freight would be moved out of the aircraft’s third zone compartment, and into the nose storage compartment.

The resulting discrepancy between the pilot’s planned load and trim sheet, and the actual load distribution on the aircraft, was not initially enough to put the aircraft’s centre of gravity outside the allowable limits.

However, when the aircraft landed in Rockhampton, more freight was loaded into the rear half of the aircraft, and the centre of gravity shifted further aft, beyond the allowable limit.
On the second leg of the journey, the pilot reported the aircraft had a strong pitch-up tendency, and that strong forward pressure on the flight controls was required to maintain the correct pitch attitude.
During the cruise, the autopilot would not consistently maintain level flight. The pilot disconnected the autopilot and, with full nose-down trim applied, the pilot had to maintain forward pressure to control the pitch attitude of the aircraft.

After landing safely in Brisbane, the pilot discussed the incident with ground maintenance engineers, and the freight from each compartment was reweighed as it was unloaded.
The pilot subsequently completed a new load and trim sheet using the actual weights and the centre of gravity was found to be aft of the rear limit.
Additionally, when accounting for the weight added in Rockhampton, the new data showed the aircraft was actually about 6 kg above its maximum take-off weight when it initially took off from Townsville, on the first leg of its journey.

Due to fuel burn during the first leg of the flight, the aircraft had come under its weight limit by the time it landed and took off in Rockhampton.

The ATSB’s investigation found the operator’s ground handling manual did not contain detailed procedural guidance for facilitating accurate redistribution of freight and ensuring that an aircraft would be correctly loaded.

Following the incident, Toll amended its ground handling processes, and included increased direction to ensure that freight would be accurately redistributed in the event of a last-minute change.

Notably, the operator has since divested its flying operations to another operator, and relinquished its Air Operator’s Certificate. The ATSB, in consultation with Toll, contacted the new aircraft operator to discuss the potential risk of a lack in procedural guidance for ground handling.

Report: B767 brakes caught fire after high-speed rejected takeoff

A350 slid off taxiway due to poor ice control on taxiways

A Finnair Airbus A350 departing on a cargo flight to Tokyo slid partially off a slippery taxiway at Helsinki-Vantaa Airport on February 21, 2021. Substandard ice control on taxiways due to pandemic-related staff cuts was a factor, according to the newly released investigation report.

The aircraft’s no.1 engine knocked over a taxiway sign, causing superficial damage to the engine intake lip.

Factors
Due to Covid 19 pandemic and decline in traffic, the airport winter maintenance staff was cut by around fifty percent in late 2020 which affected ice control and led to non-compliances. Even during periods of major changes, such as those caused by the pandemic, an airport operator must ensure the safety of aircraft operations in the movement area or close portions of the movement area if necessary. Operational safety under difficult weather conditions must not be delegated exclusively to aircraft crews, the Safety Investigation Authority Finland (SIAF) stated.

The airport operator had carried out a major organizational change to counter the impact of the pandemic. The management and assessment of this change had rested almost entirely with the operator. The operator had not initiated adequate actions in order to manage the risks it had identified, and its reactions to observed non-compliances had been inadequate. Any major change in an operational environment also brings to the fore the role of oversight executed by the aviation authority, which should proactively address any issues noted in operators’ risk management.

Different maintenance requirements and practices were in effect for the aprons, taxiways, and runways, and the method for reporting taxiway friction and condition was less accurate than the runway condition reporting method in use at the time of the incident. Even though aircraft speeds on taxiways and aprons are low, accidents can happen under difficult weather conditions, and the usability criteria of these portions of the movement area should therefore be reassessed.

Airport maintenance had set a high threshold on limiting aircraft operations on the primary movement areas, where sufficient maintenance could have been guaranteed. There were no clear guidelines for the closure of portions of the movement area under extreme weather conditions or in other contingencies. A sophisticated safety management system shall prescribe procedures for the management of abnormal and challenging situations.

Aviation stakeholders have had difficulties in recognizing the fact that loss of aircraft control in the movement area is a serious incident. This has led to failures to initiate prescribed procedures, to application of non-standard practices, and to failures to ensure adequate communication. Published procedures should help operators to recognize the real nature of incidents and provide guidance for situations where the classification of an incident is changed.

Because the seriousness of the incident was not understood initially, the aircraft’s flight recorders were not secured appropriately after the event, and no instructions for securing the cockpit voice recorder were available to the crew members. Securing of the voice recorder is essential for determining the causes of an event and for implementing subsequent safety actions.

Recommendations
The Safety Investigation Authority Finland recommends that:

  • Finavia establishes unambiguous criteria and procedures to support decision-making for the closure of the movement area or portions thereof, or for ensuring preconditions of their safe utilization.
  • The Finnish Transport and Communications Agency establishes effective methods that will enable continued oversight of aviation stakeholders in the event of rapid and significant changes and bolster aviation organizations’ current self-monitoring procedures.
  • The Finnish Transport and Communications Agency ensures that securing of flight recorders is included in airlines’ operating procedures.