A332, Perth WA Australia, 2014
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|On 26 November 2014, an Airbus A330-200 was struck by lightning just after arriving at its allocated stand following a one hour post-landing delay after suspension of ramp operations due to an overhead thunderstorm. Adjacent ground services operatives were subject to electrical discharge from the strike and one who was connected to the aircraft flight deck intercom was rendered unconscious. The Investigation found that the equipment and procedures for mitigation of risk from lightning strikes were not wholly effective and also that perceived operational pressure had contributed to a resumption of ground operations which hindsight indicated had been premature.|
|Actual or Potential
|Ground Operations, Human Factors, Weather|
|Type of Flight||Public Transport (Passenger)|
|Intended Destination||Perth International Airport|
|Take off Commenced||Yes|
|Location - Airport|
|Airport||Perth International Airport|
|Tag(s)||Procedural non compliance,|
|Damage or injury||Yes|
|Causal Factor Group(s)|
On 29 November 2014, an Airbus A330-200 (VH-XFJ) being operated by Virgin Australia Airlines on a scheduled passenger flight from Sydney to Perth landed at destination in day VMC during a thunderstorm. After clearing the runway, ATC advised that the aircraft would have to hold position because the ramp was closed due to the risk to continued operations during the thunderstorm. After approximately an hour, the aircraft was able to taxi to its allocated gate but almost immediately lightning was seen to strike the tail of the aircraft and the ramp supervisor, who had just connected his headset to the aircraft flight crew/ground crew intercom panel in heavy rain. He received an electric shock consistent with a high voltage electrical discharge and was rendered unconscious. A nearby colleague was burned but remained conscious.
An Investigation was carried out by the Australian Transport Safety Bureau (ATSB). It was established that on the day of the occurrence, at about 1435 local time, all work on the ramp at the aircraft destination had stopped due to an electrical storm overhead. After about 40 minutes, with no further lightning activity observed on the weather radar, ground crew resumed their duties. However, soon after this, cloud-to-cloud lightning was observed and lightning struck the ramp behind a parked aircraft so all ramp work was again suspended. Thereafter, the Ramp Supervisor reported having been monitoring the situation so as to determine when it would be safe for staff to resume work.
Whilst this suspension was in force, the A330 landed and during the landing roll the crew recalled seeing lightning strike the ground about 500 metres to the right of their aircraft. The aircraft was initially instructed to hold on the taxiway because of the suspension of ramp operations. After around 15 minutes, the Airport Movement Coordinator advised the Ramp Supervisor that Virgin Operations Control in Brisbane had been in contact to ask why ramp operations had not recommenced as "other airlines had already resumed their Perth operations". The Ramp Supervisor then spoke directly to Virgin Operations Control and was "questioned directly as to why staff had not returned to the ramp" and was informed that "Virgin’s Meteorological Officer said that there had not been any lightning activity in the area for the past 30 minutes". In response, the Ramp Supervisor said that lightning was still visible overhead and was then "told to discuss this with Virgin’s Meteorological Officer" but when the attempted transfer of the call was unsuccessful, the Supervisor "hung up and reviewed the Bureau of Meteorology weather radar images" which he had access to. After assessing these, he considered that a 45 minute break in storm cell activity might be imminent. Meanwhile, the Airport Movement Coordinator "received a number of additional calls from Virgin Operations Control about the resumption of ramp duties, which were relayed to the Ramp Supervisor". After "a discussion with other senior ground crew and observing a reduction in the local storm activity", he decided that work on the ramp could resume and gave priority to clearing the backlog of aircraft waiting to be unloaded. After about an hour holding position, this meant that the A330 was able to taxi to its assigned parking gate. Once the aircraft had arrived on stand, the Ramp Supervisor personally inserted the NLG chocks and then connected a headset to the flight deck intercom jack. Other ground crew a short distance away then saw lightning strike the tail region of the A330 and simultaneously engineers in the immediate vicinity of the aircraft reported observing a lightning flash to the rear-left of the aircraft. As the Ramp Supervisor pressed the ‘push-to-talk’ button and established contact with the flight crew, he received an electrical shock consistent with a high voltage electrical discharge and was seen to stagger from the aircraft before collapsing unconscious on the ground. A second ground crew operative nearby was also subjected to the electrical discharge and sustained a burn injury but he did not lose consciousness. Both were taken to hospital for observation with the Ramp Supervisor remaining there "for a number of days before being released".
A subsequent examination of the aircraft did not find any sign of the lightning strike entry or exit points nor any defects which might have accounted for the ground crew injuries. It was considered likely that a lightning strike to an aircraft on the ground would most likely normally be earthed via the landing gear. It was noted that "Whether an aircraft is electrically earthed or not, there is a high risk of injury" to any ground crew who may be in the vicinity of an aircraft which is struck by lightning and the risk increases significantly if direct contact is being made with the aircraft at the time. Aircraft maintenance personnel should be warned of this in the aircraft type AMM. In the case of the Airbus A330, this warning read:
- "Warning: do not touch connections to the aircraft, do not use headsets. Lightning strike and high discharge currents are very dangerous for personnel and can cause damage to equipment."
The risk of a lightning strike was noted to not necessarily be affected by whether heavy rain is falling at the time and strikes may occur up to 10 nm from a storm cloud. It was found that Perth was within the coverage of two different short term thunderstorm forecasting systems - the Bureau of Meteorology's 'Automated Thunderstorm Alerting System' (ATSAS) and the commercial 'Global Positioning and Tracking System'. However, although both systems showed an increase in cloud-to-cloud lightning activity at the time of the observed strike, neither of these systems had detected any cloud-to-ground lightning strikes at or within a 5 nm radius of the airport at the time of the occurrence.
Severe weather procedures detailed in the Virgin Australia Airport Airside Operations (AAO) Manual were found to specify a stop/shutdown whenever a storm was within 5 nm of the airport. During such periods, the thunderstorm and lightning safety subsection of the AAO Manual listed activities that should not be undertaken during lightning events. These included using any headset that was connected to an aircraft and not staying in open areas or underneath an aircraft.
It was found that Virgin used a contractor to provide ground services at Perth, this contractor being one of the largest providers of such services in the country with similar operations at 15 other major airports. This contractor’s relevant procedures were found to be closely aligned with those detailed in the Virgin AAO Manual.
The Perth Airport Operator required that airlines and their contractors should "ensure that their staff were competent in airfield and ramp occupational health and safety practices" and the airport’s policy and procedures did not incorporate any specific adverse weather practices or procedures and there was no thunderstorm/lightning warning system at the airport to alert personnel working on the apron. The Airport Operator advised that they had no record of any previous injuries, serious or otherwise, attributable to aircraft lightning strikes.
It was found that about 15 minutes after the A330 had landed, when there had been no lightning strike for a period of 30 minutes, the Ramp Supervisor had come under pressure to authorise the resumption of airside operations and had eventually agreed to this. He told the Investigation that "had he not felt pressured by the (Virgin) Operations Controller and Airport's Aircraft Movement Coordinator, he would most likely not have resumed work on the ramp at that time".
The Investigation concluded that the available evidence pointed to the observed lightning strike having been to the tail of the aircraft rather than direct to the surface in that vicinity and that the serious injuries to the Ramp Supervisor appeared likely to be a result of such a strike discharging through the headset and the Ramp Supervisor to earth - a ‘contact’ strike. It was concluded that the less serious injury to the second ground crew member close by was probably the consequence of a ‘side flash’ strike.
The Conclusion of the analysis of evidence available made by the Investigation was summarised as follows:
- "Virgin’s and the ground-handling organisation’s procedures provided for local observations to be taken into account when considering the resumption of ramp duties. However, the reliance by the Operations Controller on the Meteorological Officer’s advice that lightning activity had ceased affected the application of those procedures in this case. The conversation between the Controller and the RS, and then the Airport Movement Coordinator and the RS, resulted in perceived pressure by the RS to resume ramp duties. Given the report of lightning still being observed overhead, the decision by the RS to resume those operations increased the risk of a lightning strike and injury to ground personnel."
The formally-documented Findings of the Investigation were as follows:
- In combination, perceived operational pressure by the Ramp Supervisor, and their assessment that there would be a 45-minute break in thunderstorm activity, influenced the decision to resume work on the ramp during local thunderstorm activity.
- Consistent with the observed lightning strike to the tail of the aircraft, connection of the headset to the aircraft during local thunderstorm activity resulted in a ‘contact’ strike to the Ramp Supervisor.
Other factors that increased risk:
- The Automated Thunderstorm Alerting System and Global Positioning and Tracking System data did not show cloud-to-ground lightning activity within 10 NM (19 km) of the airport prior to work resuming on the tarmac or at the time of the injuries. Despite the observed local conditions, the lack of recorded ground strikes prior to the incident may have created a false impression of a low lightning risk environment.
- The Virgin Australia Airlines Pty Ltd Meteorological Officer’s report of no lightning activity in the area in the previous 30 minutes was communicated to the Ramp Supervisor by the Operations Controller. That and the subsequent communication by the Airport Movement Coordinator was perceived by the Ramp Supervisor as pressure to resume ramp duties.
- The Ramp Supervisor’s assessment that there would be a 45-minute break in thunderstorm activity was reinforced by the report by the Operations Controller of no lightning activity in the area in the preceding 30 minutes, and the supervisor’s perception of a reduction in local storm activity.
The Investigation resulted in the following Safety Message being formulated:
- "This occurrence reaffirms that perceived or actual operational requirements should not be allowed to compromise safety. When assessing if work can resume on the airfield in the face of potentially-hazardous weather conditions, local observations of those conditions should be an integral part of the decision-making process. The final decision to resume duties should remain with the responsible person at that location."
Safety Action taken as a result of the investigated occurrence whilst the Investigation was in progress was recorded as including the following:
- Virgin Australia Airlines has:
- Enhanced its flight planning and weather training for all ground operations Airport Movement Coordinators, incorporating a specific Automated Thunderstorm Alert System training package.
- Commenced a trial of smartphone weather alert applications with key operational personnel across the domestic network.
- Commenced using wireless headsets at some airports.
- Aligned their manuals with other stakeholders’ extreme weather policy and procedures.
- Aerocare (the ground handling organisation involved) has made a number of changes to its adverse weather procedures which include:
- an increased emphasis on the fact that Ramp Supervisors have the authority to determine the cessation and recommencement of work activities.
- an increased emphasis on the risk of electrical discharge as a result of connecting a headset to an aircraft during storm activity.
- an increase in the minimum distance from storm activity at which headset connection takes place from 10 km (5.4 nm) to 18 km (9.7 nm).
- the provision of specific first aid and emergency response information in case of a lightning strike.
- enhanced guidance on the available weather-monitoring tools.
- the introduction of defined adverse weather phases as follows:
- Awareness - a forecast of adverse weather
- Watch - adverse weather within 30nm (56km) and approaching
- Alert - adverse weather within 10nm (19 km) and approaching
- Airside operational shutdown - adverse weather within 5nm (9km) and approaching
- Downgrade - adverse weather more than 5nm (9km) away and receding
- Cancellation - no thunderstorm activity forecast or observed locally
- Perth Airport has installed a thunderstorm warning system that features both audio and visual warnings to airport staff which has been used successfully on a number of occasions.
The Final Report was published on 8 March 2017. No Safety Recommendations were made.