Incident: Boeing 777 Engine Failure Incident in Denver: Pratt & Whitney PW4000 Engines

Published Date: 2021-02-22

Postmortem Analysis
Timeline 1. The software failure incident involving the Boeing 777 engine failure occurred on Saturday, as mentioned in Article 110882. 2. The incident in the Netherlands involving the Boeing 747 cargo plane engine failure occurred on Sunday afternoon, as mentioned in Article 110749. Therefore, the timeline for the software failure incidents would be: - Boeing 777 engine failure incident: Saturday - Boeing 747 cargo plane engine failure incident in the Netherlands: Sunday
System 1. Pratt & Whitney 4000-112 engines 2. Boeing 777 aircraft powered by Pratt & Whitney PW4000 engines 3. Boeing 777-200 aircraft with Pratt & Whitney PW4000 engines 4. Boeing 747-400 cargo jet with Pratt & Whitney PW4000 engine 5. Boeing 777s with Pratt & Whitney 4000 engines
Responsible Organization 1. The software failure incident in the Boeing 777 engine failure incidents was caused by the Pratt & Whitney PW4000 engines used in the aircraft [110882, 110749]. 2. The incident in the Netherlands involving a Boeing 747 cargo plane was also linked to a Pratt & Whitney engine failure [110749].
Impacted Organization 1. Boeing [110882, 110749] 2. Pratt & Whitney [110882, 110749] 3. United Airlines [110882, 110749] 4. Japan Airlines [110749] 5. All Nippon Airways [110749] 6. South Korea [110749] 7. Federal Aviation Administration (FAA) [110882, 110749] 8. National Transportation Safety Board (NTSB) [110882, 110749] 9. UK Civil Aviation Authority [110749]
Software Causes 1. The software causes of the failure incident reported in the news articles are unknown.
Non-software Causes 1. The failure incident was caused by an engine failure in the right-hand engine of the Boeing 777 aircraft, leading to debris shedding over Denver [110882]. 2. The engine failure was attributed to two fractured fan blades and other damaged blades in the engine, resulting in an uncontained and catastrophic engine failure [110882]. 3. The incident involved a Pratt & Whitney PW4000 engine, and similar incidents occurred with the same engine model in a Boeing 747 freighter in the Netherlands, leading to injuries and debris falling on a Dutch town [110749]. 4. The failure incident led to the grounding of more than a hundred Boeing 777s fitted with Pratt & Whitney PW4000 engines, impacting United Airlines, Japan's main airlines, and a South Korean firm [110749].
Impacts 1. The software failure incident involving the Boeing 777 engine failure led to the grounding of all 128 planes of its Boeing 777-200's that use Pratt & Whitney PW4000 engines for inspections by US regulators and other aviation authorities [110749]. 2. United Airlines and Japan's two main airlines suspended operations of 56 planes fitted with the same engine that disintegrated mid-flight over Colorado, leading to flight disruptions and potential financial losses [110749]. 3. The incident resulted in Japan requesting airlines to avoid using Boeing 777 planes with Pratt & Whitney 4000 engines for take-offs, landings, and overflights in its territory until further notice, impacting air travel operations in the region [110749]. 4. The UK banned all Boeing 777s with PW4000 engines from flying over British airspace until further notice, affecting international flight routes and causing disruptions in air travel schedules [110749]. 5. The software failure incident caused a significant drop in the share price of Raytheon, the parent company of Pratt & Whitney, by 2.77%, impacting the financial performance of the company and potentially affecting investor confidence [110747].
Preventions 1. Enhanced inspection procedures for hollow fan blades unique to the Pratt & Whitney 4000 engine used on Boeing 777 airplanes could have potentially prevented the incident [110882, 110749]. 2. Improved oversight and regulatory measures by the Federal Aviation Administration (FAA) and other civil aviation authorities could have helped in identifying and addressing potential risks associated with the engine model [110882, 110749]. 3. Timely maintenance and adherence to safety protocols by the airline operators and aircraft manufacturers could have played a role in preventing the engine failure incident [110882, 110749]. 4. Implementation of more robust safety measures and emergency response protocols in case of engine failures could have mitigated the impact of the incident [110882, 110749].
Fixes 1. Conducting immediate and stepped-up inspections of Boeing 777 aircraft with Pratt & Whitney PW4000 engines to identify any potential issues and ensure safety [110882, 110749]. 2. Implementing an Emergency Airworthiness Directive to require inspections of Boeing 777 airplanes equipped with certain Pratt & Whitney PW4000 engines [110749]. 3. Grounding all 128 Boeing 777s with Pratt & Whitney PW4000 engines until inspections are completed and safety is ensured [110749]. 4. Coordinating with planemakers and federal regulators to ensure the safe operation of the fleet and investigate the incidents thoroughly [110749]. 5. Working closely with civil aviation authorities to share safety data and information with affected operators [110749]. 6. Banning Boeing 777s with PW4000 engines from flying over British airspace until further notice [110749]. 7. Ordering airlines to avoid using Boeing 777 planes with Pratt & Whitney 4000 engines for take-offs, landings, and overflights in Japan [110749]. 8. Reviewing safety protocols and procedures to prevent similar incidents in the future [110882, 110749]. 9. Addressing any potential design flaws or issues with the Pratt & Whitney PW4000 engines to prevent engine failures [110882, 110749].
References 1. Boeing [110882, 110749, 110747] 2. Pratt & Whitney [110882, 110749, 110747] 3. Federal Aviation Administration (FAA) [110882, 110749, 110747] 4. National Transportation Safety Board (NTSB) [110882, 110749] 5. United Airlines [110882, 110749, 110747] 6. Japan Airlines [110749] 7. All Nippon Airways [110749] 8. South Korean regulators [110882] 9. Broomfield Police Department [110882, 110747] 10. Transportation Secretary Grant Shapps [110749] 11. Japan Aeronautical Service Information Center [110749] 12. Raytheon [110749, 110747] 13. Aviation safety expert John Cox [110882] 14. Greg Waldron, managing editor at Flight Global [110747] 15. Former National Transportation Safety Board Chairman Jim Hall [110882, 110747] 16. Kirby Klements, Denver resident [110882] 17. Tyler Thal, Broomfield resident [110882] 18. Kieran Cain, local resident [110882] 19. Travis Loock, passenger on the flight [110882]

Software Taxonomy of Faults

Category Option Rationale
Recurring one_organization, multiple_organization (a) The software failure incident having happened again at one_organization: - Boeing faced another blow after the engine failure incident with its 777-model aircraft, following the grounding of its 737 Max aircraft for 18 months due to two aviation accidents that resulted in 346 fatalities [110882]. - Pratt & Whitney, the engine manufacturer involved in the recent incident, had another engine failure incident in the Netherlands involving a Boeing 747 freighter, which dropped debris onto a Dutch town and injured two people [110749]. (b) The software failure incident having happened again at multiple_organization: - Japan Airlines had a similar incident in December 2020 when the crew requested an emergency landing due to a malfunction in the left engine, similar to the recent incident involving a Boeing 777 [110749].
Phase (Design/Operation) design, operation (a) In the reported software failure incident related to the Boeing 777 engine failure, the incident was primarily attributed to a failure in the design phase. The failure was linked to the Pratt & Whitney PW4000 engines used in the aircraft. The National Transportation Safety Board (NTSB) found that two of the engine's fan blades were fractured, and the remaining blades exhibited signs of damage. The incident highlighted the need for inspections of Boeing 777 jets with Pratt & Whitney 4000 engines, specifically focusing on the hollow fan blades unique to this model of engine [110749]. (b) The software failure incident was also influenced by operational factors. Passengers on the United Airlines flight reported hearing a loud explosion and experiencing shaking and fear during the incident. The pilot had to make a mayday call to air traffic control after the engine failure occurred shortly after take-off. The incident led to debris falling from the plane onto the Denver suburbs, narrowly missing homes and other buildings. Fortunately, the pilot successfully executed an emergency landing back in Denver, ensuring the safety of all passengers and crew on board [110747].
Boundary (Internal/External) within_system, outside_system (a) within_system: The software failure incident related to the Boeing 777 engine failure is primarily within the system. The incident involved an engine failure on a United Airlines flight, leading to debris falling from the plane and the engine catching fire. The failure was attributed to issues within the engine itself, specifically related to the Pratt & Whitney PW4000 engines used on the Boeing 777 aircraft. Investigations by the National Transportation Safety Board (NTSB) focused on the fractured fan blades and other damage within the engine [110882, 110749]. (b) outside_system: The software failure incident related to the Boeing 777 engine failure can also be considered to have contributing factors originating from outside the system. This is evident in the response from regulatory authorities and airlines, such as the Federal Aviation Administration (FAA) and Japan's Ministry of Land, Infrastructure, Transport and Tourism, which issued orders to ground planes with similar engines and implement inspections. Additionally, the incident led to a drop in share prices for Raytheon, the parent company of Pratt & Whitney, indicating external repercussions [110882, 110749].
Nature (Human/Non-human) non-human_actions (a) The software failure incident occurring due to non-human actions: - The software failure incident involving the Boeing 777 engine failure was primarily attributed to an uncontained engine failure, where debris erupted from the engine during the flight, causing damage to the aircraft and posing a potential threat to passengers and people on the ground [110882]. - The incident led to the grounding of Boeing 777 aircraft with Pratt & Whitney PW4000 engines, affecting multiple airlines and prompting emergency inspections and safety measures by aviation authorities [110749]. - The National Transportation Safety Board (NTSB) investigated the incident, focusing on the fractured fan blades and other damage in the engine, indicating a mechanical failure rather than a human-induced issue [110749]. (b) The software failure incident occurring due to human actions: - The articles do not mention any specific human actions or errors that directly contributed to the software failure incident involving the Boeing 777 engine failure. The focus of the investigation and response was primarily on mechanical issues and safety measures related to the engine failure [110882, 110749]. - The incident was described as a rare and dangerous occurrence, highlighting the potential risks associated with uncontained engine failures in aircraft, but there was no indication of human error playing a significant role in the incident [110882, 110749].
Dimension (Hardware/Software) hardware (a) The software failure incident occurring due to hardware: - The incident involving the Boeing 777 engine failure was primarily a hardware-related issue. The failure of the engine, specifically the Pratt & Whitney 4000 engine, led to debris being shed over Denver and in the Netherlands [110882, 110749]. - The National Transportation Safety Board (NTSB) reported that two fan blades in the engine were fractured, and the remaining blades exhibited signs of damage, indicating a hardware failure within the engine [110749]. - The incident led to the grounding of Boeing 777s with Pratt & Whitney PW4000 engines, highlighting the hardware-related safety concerns [110747]. (b) The software failure incident occurring due to software: - There is no indication in the articles that the software failure incident was directly caused by software issues. The focus of the incidents was on hardware failures in the engines of the Boeing 777 aircraft [110882, 110749, 110747]. - The articles primarily discuss engine failures, inspections, and safety concerns related to the hardware components, with no mention of software contributing to the incidents.
Objective (Malicious/Non-malicious) non-malicious (a) The software failure incident related to the Boeing 777 engine failure is non-malicious. The incident involved an engine failure on a United Airlines flight, leading to debris falling from the plane and the engine catching fire. The failure was attributed to a catastrophic engine failure, specifically in the right-hand engine of the aircraft, which resulted in debris being scattered over a residential area in Denver [110882, 110749]. The National Transportation Safety Board (NTSB) is conducting an investigation into the incident to determine the cause of the engine failure. Initial findings indicated that two fan blades in the engine were fractured, and the remaining blades exhibited signs of damage. The NTSB stated that it was too early to draw conclusions about how the incident occurred [110749]. The Federal Aviation Administration (FAA) issued an Emergency Airworthiness Directive requiring immediate or stepped-up inspections of Boeing 777 aircraft with Pratt & Whitney PW4000 series engines after the engine failure on United Flight 328. The FAA Administrator, Steve Dickson, mentioned that the inspection interval should be stepped up for the hollow fan blades unique to this model of engine used on Boeing 777 airplanes [110749]. In summary, the incident was a non-malicious software failure related to an engine malfunction on the Boeing 777 aircraft, leading to safety concerns and the grounding of similar aircraft for inspections and investigations.
Intent (Poor/Accidental Decisions) accidental_decisions (a) The intent of the software failure incident was accidental_decisions. The software failure incident related to the Boeing 777 engine failure was primarily caused by an accidental event rather than poor decisions. The incident involved an uncontained engine failure on a United Airlines flight, leading to debris falling from the aircraft over Denver. The failure was attributed to a fracture in two fan blades and damage to the remaining blades, resulting in the engine catching fire and emitting smoke [110882]. Additionally, a similar incident occurred in the Netherlands involving a Boeing 747 freighter with a Pratt & Whitney engine, further indicating an accidental failure rather than poor decisions [110749].
Capability (Incompetence/Accidental) accidental (a) The software failure incident occurring due to development_incompetence: - The incident involving the Boeing 777 engine failure was not related to software failure but rather an engine failure incident [Article 110882]. - The failure was attributed to an uncontained engine failure, where debris erupted from the engine, causing damage to the aircraft [Article 110882]. - The incident was described as a rare but dangerous occurrence, with experts noting that uncontained failures are very rare and more dangerous [Article 110882]. (b) The software failure incident occurring due to accidental factors: - The incident involving the Boeing 777 engine failure was not related to software failure but rather an engine failure incident [Article 110882]. - The failure was described as a rare and dangerous incident, with debris erupting from the engine and causing damage to the aircraft [Article 110882]. - The incident was noted to have similarities with a previous engine failure incident on a United Airlines flight in 2018, raising questions about the response to such incidents by manufacturers and regulators [Article 110882].
Duration temporary The software failure incident related to the Boeing 777 engine failure is temporary. The incident was caused by a specific issue related to the Pratt & Whitney PW4000 engines used on the aircraft. The failure led to the grounding of Boeing 777s with these engines for inspections and further investigation by aviation authorities ([110882], [110749], [110747]).
Behaviour crash, other (a) crash: The software failure incident in the news articles can be categorized as a crash. The incident involved an engine failure on a Boeing 777 aircraft, leading to the engine exploding and shedding debris over Denver. This resulted in the aircraft experiencing a catastrophic engine failure shortly after take-off, forcing it to make an emergency landing back in Denver [110882, 110749]. (b) omission: The software failure incident did not involve an omission where the system omitted to perform its intended functions at an instance(s). Instead, the failure was more related to the engine malfunction and subsequent shedding of debris. (c) timing: The software failure incident did not involve a timing issue where the system performed its intended functions correctly but too late or too early. The incident was more related to the engine failure and the subsequent emergency landing. (d) value: The software failure incident did not involve a value issue where the system performed its intended functions incorrectly. The focus was on the engine failure and the safety implications rather than the software directly causing incorrect functions. (e) byzantine: The software failure incident did not exhibit a byzantine behavior where the system behaved erroneously with inconsistent responses and interactions. The incident was more related to the physical engine failure and its consequences. (f) other: The behavior of the software failure incident can be described as a system failure leading to a physical malfunction. The incident involved the Pratt & Whitney engine on the Boeing 777 aircraft experiencing a failure, shedding debris, and necessitating an emergency landing, rather than a direct software malfunction [110882, 110749].

IoT System Layer

Layer Option Rationale
Perception None None
Communication None None
Application None None

Other Details

Category Option Rationale
Consequence death, harm, property, non-human (a) death: People lost their lives due to the software failure - The incident involving the Boeing 737 Max aircraft was mentioned, where two aviation accidents resulted in the deaths of 346 people [Article 110882]. (b) harm: People were physically harmed due to the software failure - In the incident involving the Boeing 747-400 cargo jet in the Netherlands, two people were injured after the engine burst into flames and debris fell on the town of Meerssen [Article 110749]. (d) property: People's material goods, money, or data was impacted due to the software failure - Debris from the United Airlines flight fell on the Denver suburbs, narrowly missing homes and other buildings, causing damage to property [Article 110749]. (f) non-human: Non-human entities were impacted due to the software failure - The incident involving the Boeing 747-400 cargo jet in the Netherlands resulted in debris falling on the town of Meerssen, causing damage to property and injuring two people [Article 110749].
Domain information, transportation (a) The incident involved a Boeing 777 aircraft with a Pratt & Whitney engine failure, leading to the grounding of multiple planes. The system failure impacted the production and distribution of information related to the aviation industry, specifically affecting the operations of United Airlines and other carriers using the same model of aircraft engine [110882, 110749]. (b) The failure incident affected the transportation industry as it involved a United Airlines flight that experienced engine failure shortly after take-off, leading to an emergency landing. This incident disrupted the transportation of passengers and cargo on the affected aircraft [110882, 110749]. (m) The failure incident was not directly related to any other industry beyond the aviation and transportation sectors as reported in the articles.

Sources

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