CSB: 12 Years of Deficiencies Prior to Fatal Plant Explosion
CSB: 12 Years of Deficiencies Prior to Fatal Plant Explosion The US Chemical Safety and Hazard Investigation Board (the CSB) has released its final report into an explosion and fire at the Williams Olefins ethylene and propylene plant in Geismar, Louisiana (20 miles SE of Baton Rouge), on 13 June 2013, which killed two employees. The CSB concluded that process safety management deficiencies during the 12 years prior “allowed a type of heat exchanger called a ‘reboiler’ to…overpressure, and ultimately rupture, causing the explosion”. The Accident The unit that failed was approximately 18.5 feet long and over 5 feet in diameter and was one of a pair that were designed in 1967 to be operated together. In 2001, Williams had made modification to enable one reboiler to be isolated at a time, allowing continuous operation with one unserviceable. The CSB say: The incident occurred during non-routine operational activities that introduced heat to the reboiler, which was offline and isolated from its pressure relief device. The heat increased the temperature of a liquid propane mixture confined within the reboiler, resulting in a dramatic pressure rise within the vessel. The reboiler shell catastrophically ruptured, causing a boiling liquid expanding vapor explosion (BLEVE) and fire, which killed two workers; 167 others reported injuries, the majority of which were contractors. The facility normally employed 110 people but at the time of the incident, around 800 contractors were working on a plant expansion. Safety Analysis The CSB say there were failures to: Appropriately manage or effectively review two significant changes that introduced new hazards involving the reboiler that ruptured: (1) the installation of block valves that could isolate the reboiler from its protective pressure relief device and (2) the administrative controls Williams relied on to control the position (open or closed) of these block valves. Effectively complete a key hazard analysis recommendation intended to protect the reboiler that ultimately ruptured. Perform a hazard analysis and develop a procedure for the operations activities conducted on the day of the incident that could have addressed overpressure protection. The CSB produced this ‘accimap‘: These failures developed over a 12 year incubation phase (consistent with the concepts of Barry Turner in his seminar 1978 work Man- Made Disasters): The CSB say their case study on the incident highlights the importance of: Using a risk-reduction strategy known as the “hierarchy of controls” to effectively evaluate and select safeguards to control process hazards. This strategy could have resulted in Williams choosing to install a pressure relief valve on the reboiler that ultimately ruptured instead of relying on a locked open block valve to provide an open path to pressure relief, which is less reliable due to the possibility of human implementation errors; Establishing [what the CSB call] a strong organizational process safety culture. A weak process safety culture contributed to the performance and approval of a delayed Management of Change (MOC) that did not identify a major overpressure hazard and an incomplete Pre-Startup Safety Review (PSSR); Developing robust process safety management programs, which could have helped to ensure Process Hazard Analysis (PHA) action items were implemented effectively; and Ensuring continual vigilance in implementing process safety management programs to prevent major process safety incidents. Safety Actions and Safety Recommendations Williams has since implemented improvements which include redesigning the reboilers to prevent isolation from their pressure relief valves. Before the incident, the Williams...
read moreLOC-I Departure: AAIB Report on King Air 200 Accident
Loss of Control – Inflight Departure: AAIB Report on KA200 Accident We look at three aspects from the investigation into a fatal air accident in the UK: Recording of aircraft defects, Terrain Avoidance Warning Systems (TAWS) and the carriage of non-crew members on the flight deck. The UK Air Accidents Investigation Branch (AAIB) has recently issued its report into the fatal Loss of Control – Inflight (LOC-I) accident on 3 October 2015 to Beechcraft B200 Super King Air, G-BYCP. The aircraft was operated by London Executive Aviation (LEA), described in contemporary trade press report as “UK’s largest charter and management company”. LEA is now part of the Luxaviation Group “the second largest corporate aircraft operator in the world”, according to their website. History of the Flight The AAIB explain: G-BYCP was planned to operate a non-commercial flight from Stapleford Aerodrome [Essex] to RAF Brize Norton [Oxfordshire] with two company employees on board (including the pilot) to pick up two passengers for onward travel. The aircraft [type] is approved [both in terms of aircraft type certification and approval of the operator] for operation by a single pilot, or by two pilots. The pilot (the aircraft commander) held a Commercial Pilot’s Licence (CPL) and occupied the left seat and another pilot, who held an Airline Transport Pilot’s Licence (ATPL), occupied the right. …his licence was valid on Bombardier Challenger 300 and Embraer ERJ 135/145 aircraft and not on the King Air. The pilot reported for work at approximately 0715 hrs for a planned departure at 0815 hrs but he delayed the flight because of poor meteorological visibility. At approximately 0915 hrs, trees were visible just beyond the end of Runway 22L, indicating that visibility was at least 1,000 m and the pilot decided that conditions were suitable for departure. The operator’s Operations Manual Part A (OMA) stated that the minimum visibility for any takeoff in the King Air would be 500 m. Having gained a departure clearance at 0908: The aircraft took off at 0921 hrs and was observed climbing in a wings level attitude until it faded from view shortly after takeoff. The aircraft was climbing through approximately 750 ft amsl after takeoff when it began to turn right. It continued to climb in the turn until it reached approximately 875 ft amsl when it began to descend. The descent continued [for about 11 seconds, with the rate of descent reaching 7000ft/min ] until the aircraft struck some trees at the edge of a field, approximately 1.8 nm southwest of the aerodrome. Eye witnesses capture video of the immediate accident site: The aircraft was not fitted with a CVR, FDR or [certified] TAWS equipment and was not required to be so, in accordance with relevant airworthiness and operational regulations. EASA are rulemaking in these areas. Rulemaking tasks RMT.0271 and RMT.0272 refer on CVRs and FDRs (as we discussed in 2014) and a Notice of Proposed Amendment (NPA) is planned for issue in Quarter 1 of 2016. An NPA has already been issued on TAWS (discussed below). AAIB Conclusions The AAIB concluded: Examination of the powerplants showed that they were probably producing medium to high power at impact. There was contradictory evidence as to whether or not the left inboard flap was fully extended at impact but it was concluded that the aircraft would have been controllable even if there had been a flap asymmetry. The possibility of...
read moreOffshore Renewables Aviation Guidance (ORAG) Issued
Offshore Renewables Aviation Guidance (ORAG) Issued: Good Practice Guidelines for Offshore Renewable Energy Developments Earlier in the year RenewableUK issued their Offshore Renewables Aviation Guidance (ORAG), which was discussed at a session at Helitech earlier this month. RenewableUK is the UK’s leading not for profit renewable energy trade association. The ORAG is a guide to aviation good practice for offshore wind energy projects, collaboratively produced by a range of stakeholders. Its purpose: …is to inform and educate [wind farm] Duty Holders so that they can design, integrate, and contract aviation assets into their installation and O&M operations; and act as intelligent customers and / or supervisors of aviation services. It provides a framework to develop consistent and coherent aviation support strategies for the offshore energy industry. The ORAG is designed not only for organisations that are considering helicopters to support the operation of their offshore wind farms but also those that don’t but need to be aware of how their project may affect aviation (including search and rescue). https://youtu.be/SlMe-X0uewY This H135 is operated by Unifly. The guide is timely as several presentations at (and around) Helitech highlighted the massive growth that is likely in helicopter use as larger offshore wind farms and their sub-stations are constructed further offshore. The Crown Estate provide an overview of developments in the UK. Many more countries are paying attention to the potential of wind energy (e.g Mauritius) and it is just reported that DONG Energy are considering selling their oil and gas business to concentrate on wind energy. Some studies are predicting close to a 1000 helicopters globally by 2030, ranging from light twins doing helicopter hoist transfers to wind turbine nacelles to heavy helicopters operating to in-field support vessels and distant ‘hub’ platforms. See also our recent article: First AW169 for Offshore Wind Turbine Support that discusses the Siemens Gemini Project (a EUR 1.5mn project off the Netherlands that features 150 turbines, with 130m diameter blades, delivering a total of 600MW [enough to power 800,000 home]s). Two Leonardo AW169s will be operated by Heli Service International. Meanwhile, Wiking Helikopter Services has has taken delivery of the first of two Airbus Helicopters H145s to expand their fleet. The ORAG is structured as follows: Unlike some other guidance documents, such as the International Association of Oil & Gas Producers (IOGP) Aviation Management Guidelines (Report 390) (soon to be revised as Report 590), it is more about the customer making intelligent decisions when contracting aviation rather than a shopping list of requirements for air operators to meet. UPDATE 11 April 2017: Westermost Rough Crew Transfer Case Study UPDATE 21 May 2017: In the same week that 8MW turbines, the largest in commercial operation in the world, start operating at the Burbo Bank Extension off Merseyside (each producing more power than the entire first offshore wind farm at Vindeby, opened in 1991), McKinsey publish Winds of change? Why offshore wind might be the next big thing. McKinsey say: ….by 2024, 13- to 15-megawatt models will likely hit the market. This reduces the cost per megawatt. Even as turbines have become larger, they have also become better. In the 1990s, the expected lifetime of offshore wind parks was only 15 years; now it is closer to 25 years, and new sites project an operational lifetime of 30 years. They go on: Offshore wind developers vary widely in their operations and maintenance performance. The best drive down costs while maintaining high availability and safety standards; the rest tend to...
read moreEASA Opinion on Ageing Aircraft Structures (Opinion 12/2016)
EASA Opinion on Ageing Aircraft Structures (Opinion 12/2016) The European Aviation Safety Agency (EASA) has recently issued Opinion 12/2016 on ageing aircraft structures, and specifically the risk of ageing in the structures of turbine-powered large aeroplanes certified after 1 January 1958. EASA say: These risks include fatigue of the basic type design, widespread fatigue damage (WFD), corrosion, fatigue of changes and repairs, and continued operation with unsafe levels of fatigue cracking. Their proposal follows the NPA 2013-07 consultation, which resulted in 674 comments by 48 stakeholders. The Opinion has now gone to the European Commission as part of the rule making process for the 32 EASA Member States. EASA propose to mitigate the risk by amending: Regulation (EU) 2015/640 and to include new requirements in its Annex (Part-26 [i.e. CS-26] — ‘Additional airworthiness requirements for operations’). This is to address the issue of ageing aircraft structure for the current fleet and improve the requirements for future aircraft designs, noting that similar provisions to address ageing aircraft safety exist within the US rules for continued airworthiness and safety improvements for large aeroplanes. Regulation (EU) No 748/2012, Annex I (Part-21) ‘Certification of aircraft and related products, parts and appliances, and of design and production organisations’ to reference Part-26 in order to ensure that TCHs (type certificate holders) and STCHs (supplementary type certificate holders) address the effects of ageing aircraft structures as part of the approval of type certificates, changes and repairs. Regulation (EU) No 1321/2014, Annex I (Part-M) to reference Part-26 in order to ensure that operators address in their maintenance programmes the effects of ageing aircraft structures. EASA explain: …the proposed ageing aircraft rule will impose new requirements for the current fleet and will include improved requirements for future aircraft designs. The proposal will ensure that Design Approval Holders (DAHs), or applicants for Type Certificates (TCs), Supplemental Type Certificates (STCs), design changes and repair approvals, will produce the necessary data, procedures, instructions and manuals related to ageing structure failures due to corrosion and fatigue and make them available to those who need to comply with them (operators). Additionally, operators will be required to incorporate these data items into their maintenance programmes while addressing the adverse effects of changes and repairs on each airframe and its associated maintenance requirements. They note that the opinion is “largely harmonised with the Federal Aviation Administration (FAA) requirements. The main concerns from the NPA consultation which were addressed were: a) Acceptance of approved data, which satisfied the FAA requirement on ageing aircraft, to comply with Part-26 requirements for ageing aircraft b) Requirement for damage tolerance inspections (DTIs) and corrosion prevention and control programmes (CPCP) for large aeroplanes below 7,500 lbs of payload or 30 passengers which is not required by the FAA requirements for ageing aircraft c) No clear provisions to exclude certain aircraft from the Part 26 applicability similar to the exemption process used by the FAA for the ageing aircraft rules. d) Implementation of a process to ensure the continuing structural integrity programme remains valid throughout the life of the aircraft. e) Difference with the FAA regarding the definition of the limit of validity (LOV) of the structural maintenance programme. f) Lack of flexibility for operators regarding means to address the adverse effects repairs and modifications may have on fatigue critical aircraft structure. g) Burden on STC holders to develop...
read moreExecuflight Hawker 700 N237WR Akron Accident: Casual Compliance
Execuflight Hawker 700 N237WR Akron Accident: Casual Compliance A disturbing accident after an unstabilised approach that begs serious questions of the operator’s procedures and culture. On 10 November 2015, HS 125-700A (Hawker 700A) N237WR, operated by Fort Lauderdale based Execuflight under 14 CFR Part 135, suffered a Loss of Control In-flight (LOC-I) during a daytime Non-Precision Approach (NPA) to runway 25 at Akron Fulton International Airport (AKR), Ohio. See the US National Transportation Safety Board (NTSB) final report and the ATC audio. The business jet impacted a four-unit apartment building near the airport and the 2 crew and 7 passengers died. No one on the ground was injured. In his opening remarks NTSB Chairman Christopher Hart said: A traveler boards an on-demand charter flight with the assumption that these government and company protections are in effect. However, in the accident that you will hear about today, we found a flight crew, a company, and FAA inspectors who fell short of their obligations in regard to safety. The Accident Flight The NTSB state in their report: Although company standard operating procedures (SOPs) specified that the pilot flying was to brief the approach, the captain [the pilot monitoring] agreed to the first officer’s request that the captain brief the approach. The ensuing approach briefing was unstructured, inconsistent, and incomplete, and the approach checklist was not completed. As a result, the captain and first officer did not have a shared understanding of how the approach was to be conducted. As the aircraft neared Akron: …the approach controller instructed the flight to reduce speed because it was following a slower airplane on the approach. To reduce speed, the first officer began configuring the airplane for landing, lowering the landing gear and likely extending the flaps to 25° (the airplane was not equipped with a flight data recorder, nor was it required to be). When the flight was about 4 nautical miles from the final approach fix (FAF), the approach controller cleared the flight for the localizer 25 approach and instructed the flight to maintain 3,000 ft mean sea level (msl) until established on the localizer. The airplane was already established on the localizer when the approach clearance was issued and could have descended to the FAF minimum crossing altitude of 2,300 ft msl. However, the first officer did not initiate a descent, the captain failed to notice, and the airplane remained level at 3,000 ft msl. As the first officer continued to slow the airplane from about 150 to 125 knots, the captain made several comments about the decaying speed, which was well below the proper approach speed with 25° flaps of 144 knots. The NTSB say this speed reduction risked an aerodynamic stall if the speed were to continue. to decay and suggest thatthe captain should have either taken control or call for a missed approach. Before the airplane reached the FAF, the first officer requested 45° flaps and reduced power, and the airplane began to descend. The first officer’s use of flaps 45° was contrary to Execuflight’s Hawker 700A nonprecision approach profile, which required the airplane to be flown at flaps 25° until after descending to the minimum descent altitude (MDA) and landing was assured… The airplane crossed the FAF at an altitude of about 2,700 ft msl, which was 400 ft higher than the published minimum crossing altitude...
read moreNHV Heliport Officially Opened in Aberdeen
NHV Heliport Officially Opened in Aberdeen The official opening of the NHV facility at Aberdeen Airport in Scotland occurred today. Following opening comments by Eric Van Hal (NHV CEO) and Jamie John (Base Manager Aberdeen), the facility was officially opened by Deirdre Michie (CEO Oil & Gas UK) and Simon Gray (CEO EEEGR). Deirdre Michie commented on the vital importance of investment across also parts of the North Sea oil and gas sector for the future of the industry. The company has two Airbus Helicopters H175 on site currently that have been on contract to Chevron since the start of the year. “Our new facilities in Aberdeen are very important for NHV to enable the company to serve its existing and future customers in one of the most strategic helicopter hubs of the industry. It will also allow us to strengthen our position in the UK market,” says Eric Van Hal. We have previously regularly reported on the heliport’s construction and the entry of service of the H175 with NHV. NHV Facility in Aberdeen (Credit: NHV) UPDATE 22 October 2016: H175 helicopters add resilience to North Sea industry, safety chief says UPDATE 24 October 2016: Persistence pays off as NHV opens Aberdeen heliport UPDATE 7 August 2018: NHV Group taking flight and winning the contracts Aerossurance has extensive helicopter safety, operations, heliport, aviation service contracting and air logistics experience. For aviation advice you can trust, contact us at: enquiries@aerossurance.com Follow us on LinkedIn and on Twitter @Aerossurance for our latest...
read moreEDA Issue Revised EMAR 145
EDA Issue Revised EMAR 145 In 2008 the European Defence Agency (EDA), an intergovernmental Agency of the European Council, created a Military Airworthiness Authorities (MAWA) Forum to help harmonise the airworthiness requirements and processes of the EDA’s 27 Participating Member States (all EU states except Denmark). This resulted in the development of a series of European Military Airworthiness Requirements (EMARs). In particular the EDA note: It has been recognised, therefore, that there exists a unique opportunity to agree on an EU-wide harmonisation and unification strategy for military airworthiness. On 4 October 2016 the EDA issued Edition 1.2 of EMAR 145, the EMAR for maintenance organisations: EMAR 145 Edition 1.2 (4 Oct 2016) – Approved EMAR 145 AMC-GM Edition 1.2 (4 Oct 2016) – Approved These were: Amended to consider EASA amendments M6-M7 and incorporation of the applicable elements of EASA Part M Subparts D & E and consistency with EMAR 66. Each document includes both side bars and a comparison table to Edition 1.1. Aerossurance are aviation consultants with extensive experience with UK and European, civil and military airworthiness regulation, including the UK MRPs and EMARs. This includes direct experience gaining/maintaining UK MAA organisational approvals. For practical aviation advice you can trust, contact us at: enquiries@aerossurance.com Follow us on LinkedIn and on Twitter @Aerossurance for our latest...
read moreCFIT Gangnam Style – Korean S-76C++ and Decision Making
CFIT Gangnam Style – Korean S-76C++ and Decision Making (HL9294) Despite poor visibility the crew of an executive helicopter pressed on and collided with a 39 storey building in Seoul. The Korean Aviation and Railway Accident Investigation Board (ARAIB) have issued their report into the accident that took place on 16 November 2013 when, a Sikorsky S-76C++ HL9294, operated by LG Electronics, crashed into a residential tower block in the Gangnam district of Seoul. Preparations for the Flight LG Electronics has a Business Support Office under which there is a Private Jet Team and a Helicopter Team (effectively two separate flight departments). The helicopter was scheduled to position from Gimpo Airport to pick up six passengers, including a Vice Chairman and CEO of LG Electronics, at the downtown, riverside Jamsil Heliport at 09:00 and take them to a company factory. This flight had been booked with 23 hours notice. Investigators say: …on 16 November, about 06:06 and 06:08, the captain called Gimpo Airport Weather Office and Seoul Airport Weather Office at home and checked out weather conditions, respectively. About 06:25, he called the [First Officer] FO and said, “Let’s cancel the flight because it will be difficult.” Subsequently, about 06:30, the FO called LG Electronics’ Vice Chairman & CEO’s Office and notified no-go due to bad weather conditions, and according to the statement of the Office, about 06:32, the Office called the Helicopter Team’s pilot in charge of operation and said, “The FO notified no-go, so please, accurately assess a situation once again.” On the day of the accident, passengers were actually considering two transportation options, high-speed train (KTX) and helicopter… …[the] passengers [had] already purchased tickets for a high-speed train and thus, were all prepared for a no-go situation… In subsequent interview it is suggested that: The reason why LG Electronics’ Vice Chairman & CEO’s Office asked the pilot in charge of operation to reassess a no-go situation is that there was time before the departure of an alternative transportation means, KTX, and that the pilot in charge of operation usually did this job whereas the FO was newly hired. The pilot in charge of operation suggested in a subsequent call with the pilot and other: “How about taking off at Gimpo Airport if the weather conditions are poor since takeoff is possible (at Gimpo Airport)”? He also gave the deputy general manager the pilots phone number. …when [the captain] talked with the Vice Chairman & CEO’s Office’s deputy general manager over the telephone at 07:12, he overturned his initial decision and deferred it until 07:40… As that time approached: …the captain decided to go forward with the operation as originally scheduled and notified this to the deputy general manager by telephone about 07:38 as well as the pilot in charge of operation through the [First Officer] FO. The FO checked weather conditions with the Jamsil Heliport’s manager by phone four times (at 07:08, 07:10, 07:52, and 08:13). He was reportedly told: “Due to fog, Cheongdam Bridge (about 1.1 km) is not visible from the heliport, and nor is the Hangang’s water (about 90 m)” … …but this was not taken into account in the captain’s decision-making process. About 08:20, the captain went to the ramp for flight where the FO was standing by after the preflight inspection. At 08:43:53…the captain requested the Tower to clear the flight for takeoff…, and at 08:44:01, the controller advised him that visibility was 700 m. Accordingly, the captain...
read moreIATA Unstable Approaches, Risk Mitigation Policies, Procedures and Best Practices
IATA Unstable Approaches, Risk Mitigation Policies, Procedures and Best Practices This 2nd Edition of this document (UPDATE: now in its 3rd edition), collaboratively written by the International Air Transport Association (IATA), the International Federation of Air Line Pilots’ Associations (IFALPA), the International Federation of Air Traffic Controllers’ Associations (IFATCA), the Civil Air Navigation Services Organisation (CANSO), has been issued. The purpose of this document is to enhance the overall awareness of the contributing factors and outcomes of unstabilized approaches, together with some proven prevention strategies and to provide a reference based upon the guidance of major aircraft manufacturers and identified industry best practice, against which to review operational policy, procedures and training. A stabilised approach is one during which several key flight parameters are controlled to within a specified range of values before the aircraft reaches a predefined point in space relative to the landing threshold, and maintained within that range of values until touchdown. Between 2011 and 2015 period, 65% of the accidents occurred during the approach and landing phases. About 14% of these accidents occurred in the presence of an unstable approach (generally related to the aircraft’s energy state) without a go around performed. Gilberto López Meyer, IARA Senior Vice President Safety and Flight Operations commented: The industry as a whole must adopt an unequivocal position that the only acceptable approach is a stabilized one, and pilots in particular must take professional pride in achieving it on every occasion. Recognized industry practice is to recommend that a failure by the flight crew to conduct a stabilized approach should result in a go-around. This new publication emphasizes the importance of pilots, air traffic controllers and airport staff working together along with regulators, training organizations and international trade associations to agree on measures and procedures to reduce unstable approaches. It is recommended that all stakeholders should use this document as a reference against which to review operational policy, procedures and training. UPDATE 9 January 2017: Unstable approach led to May 2014 hard landing of Air Canada Rouge A319 flight in Montego Bay, Jamaica UPDATE 10 March 2017: Unstable Approach Dash 8 Touches Down 450ft Before Threshold UPDATE 24 April 2017: Unstabilised Approach Accident at Aspen UPDATE 13 July 2020: ATR72 Survives Water Impact During Unstabilised Approach UPDATE 14 July 2020: IATA has warned that aggregated that FDM shows the rate of unstable approaches has been increasing during the period of reduced operations due to the 2020 COVID-19 pandemic High Airspeed and Low Engine Thrust events were key to the increase. IATA comment: Any significant deviation from planned flight path should be announced and promptly corrected. In order to ensure the safety of the flight, a go-around is required if the approach cannot be continued within stabilized approach parameters. It is important to highlight that the decision to execute a go-around is not, in any way, an indication of poor flight crew performance but rather prudent decision-making. There should be a clear non-punitive go-around policy. Aerossurance has extensive air safety, operations, airworthiness, human factors, aviation regulation and safety analysis experience. For practical aviation advice you can trust, contact us at: enquiries@aerossurance.com Follow us on LinkedIn and on Twitter @Aerossurance for our latest...
read moreEASA Issue Drone Safety Risk Portfolio and Analysis
EASA Issue Unmanned Air System (UAS) Safety Risk Portfolio and Analysis The European Aviation Safety Agency (EASA) has issued their analysis of the main safety risks involving Unmanned Aircraft Systems (UAS) / Remotely Piloted Air Systems (RPAS) / Drone operations. The aim of the study was to better understand the safety risks posed by the growing use of UAS. The study used occurrence data from both the European Central Repository (occurrences reported to NAAs of the EASA Member States) from 2010 to May 2016 and also from airlines involved in EASA’s Commercial Air Transport (CAT) Aeroplanes Collaborative Analysis Group (CAG). EASA note an “increasing trend” of reports and a “clear and significant jump in 2014”. EASA note: From these occurrences there were 42 accidents, the majority of which resulted from the crash of drone for either technical reasons or due to loss of control. None of these occurrences involved fatalities or injuries. EASA go on: The first stage in the development of the Safety Risk Portfolio involves the identification of the Key Risk Areas (Outcomes) that derive from the Occurrence Categories in the ECCAIRS Taxonomy. From the most common outcomes the Key Risk Areas can be identified (though some Occurrence Categories are not outcomes and so are disregarded). EASA do note also that “Some of the Key Risk Areas are interlinked and may give rise to another outcome”. The Key Risk Areas identified were: Airborne Conflict: The number of near-miss reports between drones and aircraft has increased significantly is the past 2 years, though EASA note that many remain unconfirmed. There have been a three collisions between drones and GA aircraft according to EASA, so far with minimal consequences. 63% of all occurrences were related to Airborne Conflict Aircraft Upset. This covers the full range of Loss of Control situations, which presents the potential for injuries to people on the ground. System Failures: These are included in the Key Areas as they could also lead to injuries to people on the ground, especially in certain types of UAS operation. Third Party Conflict: This covers the risk of collision with people or property (i.e. not aircraft) that may cause injuries or damage. Expert judgement identified this as a key risk area that could occur through causes not associated with loss of control (Aircraft Upset) or technical failure in situations where a drone operator accidentally flies into people or property. The second part of analysis for the development of the Safety Risk Portfolio involves the identification of the Safety Issues that are associated with the different Key Risk Areas. Normally, this would involve a mainly quantitative analysis however due to the lack of detail in some of the UAS data, the analysis of Event Types can only provide some indications on possible Safety Issues. The Safety Issues identified using expert judgement are: Detection, Recognition and Recovery of Deviation from Normal Operations. The Safety Issue found most frequently in terms of accidents is related to the Key Risk Area of Aircraft Upset. It specifically relates to the operators’ ability to recognise and recover from abnormal aircraft attitudes. UAS Handling and Flight Path Management. This Safety Issues is related to both Airborne Conflict and Aircraft Upset, as well as Third Party Conflict. It relates to both the normal handling of an RPAS and the planning and management of the flight path. There is also a relationship to...
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