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Report: Loss of control when entering IMC caused a fatal flight calibration Citation crash
27 January 2022
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.
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.
Maintenance error led to fatal Saab 2000 runway overrun accident, Alaska
A PenAir Saab 2000 turboprop airplane overran a runway in Alaska because its braking system was compromised by incorrectly wired anti-skid sensors, the NTSB determined.
PenAir flight 3296, overran the runway during a landing attempt in Unalaska, Alaska. The airplane crashed through the perimeter fence, crossed a road, and came to rest on shoreline rocks on the edge of Dutch Harbor. One passenger was killed; another was seriously injured; and eight sustained minor injuries, mostly during the evacuation. The flight crew, the flight attendant, and the other 29 passengers were uninjured.
A post-accident examination of the airplane revealed sensors for the anti-skid system had been incorrectly wired during an overhaul of the left main landing gear. This configuration led to the skidding and bursting of one tire and the subsequent release of brake pressure on two of the three remaining wheels. Investigators determined the loss of effective braking on three of the four main landing gear wheels prevented the flight crew from stopping on the runway.
Noting that systems should be engineered to prevent human errors that could occur during maintenance, the NTSB recommended Saab redesign the landing gear wheel speed sensor wiring to reduce the probability of a miswiring during maintenance operations. Because the captain elected to land on a runway with a reported tailwind that exceeded the airplane manufacturer’s operating limit, the airplane touched down with a higher-than-normal groundspeed. The NTSB said the decision to land with such a tailwind was “intentional, inappropriate, and indicative of plan continuation bias.”
The NTSB also found that when the Federal Aviation Administration approved PenAir to fly in and out of the Unalaska airport with the Saab 2000, they did not recognize that the safety area beyond the end of the runway did not conform to the recommended safety criteria for an airplane in that design category.
TSB Canada: better de-icing equipment and practices in remote and northern airports needed
The lack of adequate de-icing equipment and the practice of taking off without de-icing led to the fatal December 2017 accident involving a West Wind Aviation ATR-42 aircraft in Canada, according to the TSB investigation report (A17C0146).
On 13 December 2017, the ATR 42-320 aircraft departed Fond-du-Lac Airport, Saskatchewan, Canada. Shortly after takeoff, the aircraft collided with trees and terrain. The aircraft was destroyed. All 22 passengers and three crew members on board were injured, ten of them seriously. One passenger died days later.
The investigation found that, well before the accident, during the descent toward Fond-du-Lac, the aircraft encountered icing conditions. The flight crew activated both the anti-icing and de-icing systems, but some ice remained on the aircraft. However, the crew did not notice any handling abnormalities and landed without incident. During the 45 minutes on the ground prior to the accident flight, icing conditions continued to be present, and additional ice formed on the aircraft. After carrying out a pre-flight inspection, the first officer notified the captain of the presence of some ice on critical surfaces, but there was no further discussion or action taken. Because the available inspection equipment was inadequate, the first officer’s ice inspection consisted of walking around the aircraft, at night, on a dimly lit apron, without a flashlight, and looking at the left wing from the top of the stairs at the left rear entry door. As a result, the full extent of the residual ice and ongoing accretion was unknown to the flight crew.
Departing from remote airports, such as Fond-du-Lac, with some amount of surface contamination on the aircraft’s critical surfaces, had become common practice, in part due to the inadequacy of de-icing equipment or services at these locations. The past success of these adaptations resulted in the unsafe practice becoming normalized and this normalization influenced the flight crew’s decision to depart.
During takeoff, the aircraft initially climbed; however, immediately after liftoff, the aircraft began to roll to the left without any pilot input. This roll was as a result of asymmetric lift distribution due to uneven ice contamination on the aircraft. This loss of control in the roll axis, which corresponds with the known risks associated with taking off with ice contamination, ultimately led to the aircraft colliding with terrain.
This investigation also revealed a number of instances in which Transport Canada’s surveillance policies and procedures were inconsistently applied to the oversight of West Wind Aviation. For instance, between 2010 and 2013, TC had identified several concerns with West Wind’s Safety Management System (SMS). Despite this, TC decreased its surveillance of the company to a detailed inspection only every four years. When a detailed inspection did take place in 2016, it found “systemic failures” with the company’s SMS. Rather than issuing a Notice of Suspension, TC selected Enhanced Monitoring, a more moderate course of corrective action. If the application of Transport Canada’s surveillance policies and procedures is inconsistent, there is a risk that resulting oversight will not ensure that operators are able to effectively manage the safety of their operations.
Following the occurrence, West Wind has taken steps to improve its internal risk assessments, and now provides additional training, guidance, and better de-icing equipment to its crews.
Report: Take-off from closed runway highlights importance of checking NOTAMs
A Swearingen Merlin IIIB twin-turboprop aircraft sustained substantial damage when attempting to take-off from a runway that had been closed for repair works, an ATSB investigation details.
The Swearingen SA226-T Merlin had landed at Gunnedah, Australia, on the afternoon of 19 August 2020, and was parked there overnight.
The following morning, in line with a NOTAM published the previous day closing the runway from 0700 to enable runway repair works, a work crew had excavated two holes from the runway pavement (measuring 3 m wide by 5 m long and about 30 cm deep).
That afternoon, at about 1230 while the work crew was off-site from the airport during their lunchbreak, the Merlin pilot commenced a take-off run on the runway for a flight to the Gold Coast.
As the aircraft accelerated, the pilot saw the two rectangular holes excavated from the runway pavement. The pilot attempted to avoid the holes, but they were struck by the aircraft’s left main landing gear. The aircraft veered off the runway; the pilot – the sole occupant on board the aircraft – was uninjured.
The ATSB investigation found that during pre-flight planning, the pilot had not checked for relevant NOTAMs, including one stating that Gunnedah Airport was closed due to works in progress.
The investigation also found that while the work crew was away on their lunch break there was no works safety officer on site. Further, while a white cross had been placed at the main windsock, visible to aircraft arriving overhead, there were no ground-visible unserviceability markings on the runway as required by the Civil Aviation Safety Regulations Part 139 Manual of Standards (MOS) for Aerodromes. This requirement had recently been changed.
The Gunnedah Airport operator had not received notification of the updated MOS because the email included on CASA’s mailing list was for a member of staff who had left the operator. No autoreply, forwarding, or ‘hard bounce’ was in place on the email address, so CASA was not aware the email had not been received. .