Flight Diversions Research Articles

The effectiveness of supervised clustering for characterising flight diversions due to weather

Flight diversions due to adverse weather have a significant negative impact on airspace users, airports, and the environment. Previous work proposed a tree-based model that learned which flights are more likely to be diverted due to adverse weather conditions at the destination airport from historical traffic and weather data. This model was trained using confident learning to exclude from training unpredictable flight diversions caused by reasons other than weather, such as medical emergencies or technical problems. Aggregated performance metrics computed on the test set demonstrated high precision and moderate recall, and inspection of the Shapley values unravelled the most important features. Initial human observations made during the live trial, however, have raised a potential connection between the quality of predictions and the specific weather conditions that lead to flight diversions. This study aims to provide empirical evidence to support this hypothesis. To accomplish this, a data-driven methodology should be used to characterise the main conditions that cause flight diversions. Concurrently, the effectiveness of the model in each of these conditions should be evaluated. The dataset under consideration, however, presents a challenge because it contains a plethora of high-cardinality categorical features (e.g., destination airport and aircraft operator) as well as skewed numerical features with a wide range of scales (e.g., visibility and wind gust). This scenario significantly increases the difficulty of characterising the main conditions that cause flight diversions and conducting subsequent analyses even with established methods like factor analysis of mixed data. To address this challenge, this paper proposes to utilise supervised clustering, a method that combines state-of-the-art feature attribution, dimensionality reduction, and clustering algorithms to identify the most representative decisions of a model. Following that, the distinctive characteristics of the various decisions (e.g., extreme obscuration at the airport), each associated with a cluster, are determined by examining them. Finally, conventional classification and uncertainty metrics are computed for each cluster to assess the performance of the model. This paper shows that supervised clustering is effective in characterising flight diversions due to weather, and provides valuable insights into the performance of the model in different conditions, highlighting situations where predictions require careful consideration.

Assessment of the Impacts of Thunderstorm on Flight Operations at Murtala Mohammed International Airport, Ikeja, Lagos State, Nigeria

The inefficiency of the aviation industry and the persistent rise in aviation hazards have been linked to weather phenomena. As a result, researchers are looking for better solutions to the problem. The study examined the impact of thunderstorms on flight operations at Murtala Mohammed International Airport, Lagos. The data on thunderstorms and flight operations were sourced from Nigerian Meteorological Agency (NiMet) and Nigerian Airspace Management Agency (NAMA) respectively. In order to meet the research target, descriptive statistics (mean, standard deviation, and charts) and inferential statistics (Pearson’s Product Moment Correlation (PPMC) and Regression) were used. The significance level for all inferential analyses was set at 5% (0.05). The study revealed that 77.4% of thunderstorms occurred during the rainy season (April-October) while 22.6% occurred during the dry season (November-March). It also revealed some fluctuating movements of a thunderstorm in the study area. According to the findings, thunderstorms occur most frequently at the airport in June and less frequently in January and December. The study also discovered that thunderstorms at the airport are positively and significantly related to flight delays and cancellations, while the association between flight diversions and thunderstorm occurrence is positive but statistically insignificant. Furthermore, flight delays, flight diversions, and flight cancellations interact positively among themselves. The regression result of the study revealed that a 1% increase in thunderstorm occurrence leads to a 19.4% increase in flight delay, a 7.1% increase in flight cancellation, and a 4.3% increase in flight diversion. As a result, the study presented various regression models that may be utilized to make predictions. The study proposes consistent thunderstorm observation at the airport and steady forecasts using the regression models, based on the findings. However, it further recommends that pilots, air traffic controllers, and meteorologists be trained and retrained so that they can provide better and more efficient services.

Descriptive analysis of air rage incidents aboard international commercial flights, 2000–2020

Air rage has the potential to threaten the safety of flight crew and passengers. We aimed to describe the occurrence of serious air rage incidents based on a recognised scale of severity, their associated factors and outcomes. A web-based content analysis of written media reports relating to air rage incidents occurring between 2000 and 2020 was conducted. Multiple variables were extracted, including year, flight details, age and nationality of passengers, involvement of flight crew, stage of air journey, flight diversions, presence of intoxication, psychiatric history or fear of flying. A total of 270 passengers were involved in this series of air rage incidents, with 76.2% (n = 204) male. The most frequent age group for unruly passengers was 30–39 years (n = 61). Precipitating factors included alcohol consumption (55.7%, n = 127) and nicotine withdrawal (9.2%, n = 21). Flight diversions were necessitated in 35.5% (n = 81) of cases. The majority (52.6%, n = 120) of air rage incidents were categorised as level 2 on a 4-point scale of severity. The findings of this study will be of interest to the aviation industry and to air passengers and crew. Further research is needed to elucidate the precipitants of air rage. Flight crew training should incorporate early recognition and de-escalation of air rage.

Data-Driven Estimation of the Impact of Diversions Due to In-Flight Medical Emergencies on Flight Delay and Aircraft Operating Costs.

INTRODUCTION: In-flight medical emergencies (IFMEs) average 1 of every 604 flights and are expected to increase as the population ages and air travel increases. Flight diversions, or the rerouting of a flight to an alternate destination, occur in 2 to 13% of IFME cases, but may or may not be necessary as determined after the fact. Estimating the effect of IFME diversions compared to nonmedical diversions can be expected to improve our understanding of their impact and allow for more appropriate decision making during IFMEs.METHODS: The current study matched multiple disparate datasets, including medical data, flight plan and track data, passenger statistics, and financial data. Chi-squared analysis and independent samples t-tests compared diversion delays and costs metrics between flights diverted for medical vs. nonmedical reasons. Data were restricted to domestic flights between 1/1/2018 and 6/30/2019.RESULTS: Over 70% of diverted flights recover (continue on to their intended destination after diverting); however, flights diverted due to IFMEs recover more often and more quickly than do flights diverted for nonmedical reasons. IFME diversions introduce less delay overall and cost less in terms of direct operating costs and passenger value of time (averaging around 38,000) than do flights diverted for nonmedical reasons.DISCUSSION: Flights diverted due to IFMEs appear to have less impact overall than do flights diverted for nonmedical reasons. However, the lack of information related to costs for nonrecovered flights and the decision factors involved during nonmedical diversions hinders our ability to offer further insights.Lewis BA, Gawron VJ, Esmaeilzadeh E, Mayer RH, Moreno-Hines F, Nerwich N, Alves PM. Data-driven estimation of the impact of diversions due to in-flight medical emergencies on flight delay and aircraft operating costs. Aerosp Med Hum Perform. 2021; 92(2):99105.

Demystifying airline syncope.

Syncope forms a major part of medical in-flight emergencies contributing one-in-four in-flight medical events accounting to 70% of flight diversions. In such patients, it is important to elucidate the pathophysiology of syncope prior to diversion. Postural hypotension is the most common etiology of in-flight syncopal events. However, individuals without any underlying autonomic dysfunction can still experience syncope from hypoxia also known as airline syncope. Initial steps in managing such patients include positioning followed by the airway, breathing and circulation of resuscitation. These interventions need to be in close coordination with ground control to determine decision for flight diversion. Interventions which have been tried for prevention include mental challenge and increased salt and fluid intake. The current paper enhances the understanding of airline syncope by summarizing the associated pathophysiologic mechanisms and the management medical personnel can initiate with limited resources.

Urological In-Flight Medical Events on Commercial Airlines.

In-flight medical events are rare but may cause significant distress as access to care is limited. There is a paucity of data on in-flight urological medical events. We describe urological in-flight medical emergencies and report clinical and flight outcomes. We reviewed all in-flight urological medical emergencies between 2015 and 2017 from MedAire®, a ground based medical support center that provides remote medical advisory services to approximately 35% of commercial airline passenger traffic worldwide. Our primary end point was the incidence rates of in-flight urological medical events. We also characterized the types of in-flight medical emergencies, in-flight management and their impact on flight status. Statistical analyses included Student's t-tests, chi-square analysis and analysis of variance. We identified 1,368 (1%) urological in-flight medical emergencies from a total of 138,612 in-flight medical emergencies, with an incidence of 0.5 per million passengers. The most common in-flight medical emergencies were lower urinary tract symptoms (35%), urinary retention (30%) and flank pain (21%). Among in-flight medical emergencies 883 (60%) resolved in flight, 273 (28%) required on-arrival medical evaluation and 21 (1.5%) resulted in flight diversions. Of the flight diversions the majority were due to urinary retention (12, 57%) and less commonly flank pain (6, 28%) and testicular/abdominal pain (3, 15%). The most common causes of urological in-flight medical emergencies are lower urinary tract symptoms, urinary retention and renal colic, the majority of which resolved in flight. These data are useful for informing flight personnel and emergency kit equipment needs to minimize the impact of these events when they occur.

Overview, chronology, and impacts of the 2016–2017 eruption of Bogoslof volcano, Alaska

The 2016–2017 eruption of Bogoslof volcano, a back-arc shallow submarine volcano in Alaska’s Aleutian arc, began in December 2016 and included 70 explosive events and at least two episodes of subaerial dome building. Because the volcano had no local monitoring stations during the eruption, a combination of distant seismic stations, regional infrasound sensors, lightning detection, a variety of satellite data and observer reports, and a field visit in 2018, were used to recreate the events that occurred during the nine-month eruption. Following precursory seismicity that started in September 2016, the eruption began in December 2016 with a series of explosive events that persisted through mid-March 2017. After a 6-week hiatus, activity resumed on May 17 and lasted through the end of August 2017 and consisted of additional explosions and two short-lived subaerial lava domes that formed in June and August. For most of the eruption, Bogoslof’s vent was submerged in shallow seawater, though during several of the longer events a subaerial edifice grew, and the vent migrated above sea level resulting in more ash-rich volcanic clouds. Eruptive products, geophysical signals, and eruptive style are all broadly consistent with vulcanian activity where slow magma ascent led to repetitive dome or plug formation, overpressurization in the upper conduit, and sudden release during short-lived explosions. Infiltration of seawater may have prohibited large domes from forming especially in the first half of the eruption when explosions were closely spaced in time. The largest four explosions in the sequence occurred after inter-event times of 10 days or more. Three events produced ashfall on nearby communities and mariners east and south of Bogoslof and the eruption resulted in dozens of flight cancelations and flight diversions around the volcano and its ash clouds.

Epidemiology of Medical Events on a Commercial African National Airline Carrier Between 2009 and 2011

Introduction: An estimated 3.8 billion passengers traveled on commercial aircraft in 2016, of whom close to 1.5 billion crossed international boundaries. Modern commercial aircrafts can carry up to 800 passengers and can fly more than 18 hours. Although not very common, in-flight medical incidents can result in flight diversions that are costly and extremely inconvenient. The aim of the current study was to review in-flight medical incidents on a commercial African carrier between 2009 and 2011. Methods: A secondary analysis of data collected by air stewards during in-flight medical events that were recorded in a register were retrieved for the 3-year period 2009-2011. All medical documented data was evaluated. Results: A total of 3306 medical events equating to an average of 155 cases per million passengers per year were documented over the 3-year study period, of which 3279 were specified into medical categories. Cardiovascular cases (1124; 34.0%) gastrointestinal (727; 22.0%), muscular-skeletal (302; 9%), and respiratory (202; 6%) were the most common cases. Most incidents (74%) were managed by the cabin crew. Five of the medical incidents led to diversions. There were 9 deaths on board over the 3-year period. Conclusion: In-flight medical incidents are rare events. Comparisons with other airlines is difficult due to the non-standardization of recording methods. A global uniform reporting format across all airlines is necessary. Further research is required to determine the factors associated with medical incidents so that pre-emergency preparedness plans can be strengthened.

Prognostic Factors for Outcomes of In-Flight Sudden Cardiac Arrest on Commercial Airlines.

In-flight cardiac arrest (IFCA) is a relatively rare but challenging event. Outcomes and prognostic factors are not entirely understood for victims of IFCAs in commercial aviation. This was a retrospective cohort study of airline passengers who experienced IFCA. Demographic and operational variables were studied to identify association in a multivariate logistic regression model with the outcome of survival-to-hospital. In-flight medical emergencies were processed by a ground-based medical center. Subsequent comparisons were made between reported shockable-rhythm (RSR) and reported non-shockable-rhythm (RNSR) groups. Logistic regression was also used to identify predictors for shock advised and flight diversions using a case control study design. Significant predictors for survival-to-hospital were RSR and remaining flight time to destination. The percentage of RSR cases was 24.6%. The survival to hospital admission was 22.7% (22/97) for passengers in RSR compared with 2.4% (7/297) in the RNSR group. The adjusted odds ratio for survival-to-hospital for the RSR group compared to the RNSR group was 13.6 (5.5-33.5). The model showed odds for survival to hospital decreased with longer scheduled remaining flight duration with adjusted OR = 0.701 (0.535-0.920) per hour increase. No correlation between diversions and survival for RSR cases was found. Survival-to-hospital from IFCAs is best when an RSR is present. The percentage of RSR cases was lower than in other out-of-hospital cardiac arrest (OHCA) settings, which suggests delayed discovery. Flight diversions did not significantly affect resuscitation outcome. We emphasize good quality cardio-pulmonary resuscitation (CPR) and early defibrillation as key factors for IFCA survival. Alves PM, DeJohn CA, Ricaurte EM, Mills WD. Prognostic factors for outcomes of in-flight sudden cardiac arrest on commercial airlines. Aerosp Med Hum Perform. 2016; 87(10):862-868.

Improving Disruption Management With Multimodal Collaborative Decision-Making: A Case Study of the Asiana Crash and Lessons Learned

Transportation networks constitute a critical infrastructure enabling the transfers of passengers and goods, with a significant impact on the economy at different scales. Transportation modes are coupled and interdependent. The frequent occurrence of perturbations on one or several modes disrupts passengers' entire journeys, directly and through ripple effects. Collaborative decision-making has shown significant benefits at the airport level, both in the U.S. and in Europe. This paper examines how it could be extended to the multimodal network level, discusses the supporting evidence, and provides recommendations for implementation. A case study on the disruption management following the Asiana Crash at San Francisco International Airport is presented. The crash led to a large number of flight diversions to many airports, such as Oakland, Los Angeles, but also Seattle for instance, disrupting the journeys of thousands of passengers. Passenger reaccommodation varied greatly from airline to airline and airport to airport. First, a passenger-centric reaccommodation scheme is developed to balance costs and delays, for each diversion airport. Second, assuming better information sharing and collaborative decision-making, we show that there was enough capacity at the neighboring airports, Oakland and San Jose, to accommodate most of the diverted flights and reoptimize the allocation of flight diversions to the Bay Area airports. Based on this case study, recommendations for the adoption of multimodal CDM are elaborated. This paper paves the way for further data-driven research for increased resilience of passenger door-to-door journeys.

Detecting flight trajectory anomalies and predicting diversions in freight transportation

Timely identifying flight diversions is a crucial aspect of efficient multi-modal transportation. When an airplane diverts, logistics providers must promptly adapt their transportation plans in order to ensure proper delivery despite such an unexpected event. In practice, the different parties in a logistics chain do not exchange real-time information related to flights. This calls for a means to detect diversions that just requires publicly available data, thus being independent of the communication between different parties.The dependence on public data results in a challenge to detect anomalous behavior without knowing the planned flight trajectory.Our work addresses this challenge by introducing a prediction model that just requires information on an airplane's position, velocity, and intended destination. This information is used to distinguish between regular and anomalous behavior.When an airplane displays anomalous behavior for an extended period of time, the model predicts a diversion. A quantitative evaluation shows that this approach is able to detect diverting airplanes with excellent precision and recall even without knowing planned trajectories as required by related research. By utilizing the proposed prediction model, logistics companies gain a significant amount of response time for these cases.

From Albania to Zambia: Travel Back to Country of Origin as a Goal of Care for Terminally Ill Patients

With unprecedented levels of international migration, physicians in the United States may care for terminally ill patients who have strong connections to their country of origin and such patients may desire to return in the final stages of life. In this study, we analyzed how often terminally ill patients cited travel to country of origin as a goal of care, how often travel occurred, and factors associated with successful travel. A retrospective chart review from January 1, 2005 through May 1, 2007. All foreign-born patients seen by a palliative care consultation service, including inpatient and outpatient consultations, in an urban safety-net health system in the United States. We determined whether patients expressed a desire to travel to their country of origin and the factors, including demographics and functional status associated with travel. Of 336 foreign-born patients, 129 (38%) expressed a desire to travel to their country of origin; 60 (47%) successfully returned to 24 unique countries. Countries to which the largest number of patients returned were Mexico (n=14), Poland (n=11), and the Philippines (n=7). Although patients with the best functional status were most likely to travel successfully, 16 (31%) who wanted to travel despite having the worst functional status (Eastern Cooperative Oncology Group [ECOG] score indicating confinement to bed or chair) traveled successfully. There were no deaths en route or flight diversions due to medical crisis; all trips were made on regularly scheduled commercial airline flights. A substantial proportion of patients in our cohort expressed a desire to return to their country of origin. We facilitated successful travel for nearly half of these patients. Our findings identify the need to include travel back to country of origin in the framework of planning care for terminally ill patients.

Air Travel and Pneumothorax

The number of medical emergencies onboard aircraft is increasing as commercial air traffic increases and the general population ages, becomes more mobile, and includes individuals with serious medical conditions. Travelers with respiratory diseases are at particular risk for in-flight events because exposure to lower atmospheric pressure in a pressurized cabin at cruising altitude may result in not only hypoxemia but also pneumothorax due to gas expansion within enclosed pulmonary parenchymal spaces based on Boyle's law. Risks of pneumothorax during air travel pertain particularly to those patients with cystic lung diseases, recent pneumothorax or thoracic surgery, and chronic pneumothorax. Currently available guidelines are admittedly based on sparse data and include recommendations to delay air travel for 1 to 3 weeks after thoracic surgery or resolution of the pneumothorax. One of these guidelines declares existing pneumothorax to be an absolute contraindication to air travel although there are reports of uneventful air travel for those with chronic stable pneumothorax. In this article, we review the available data regarding pneumothorax and air travel that consist mostly of case reports and retrospective surveys. There is clearly a need for additional data that will inform decisions regarding air travel for patients at risk for pneumothorax, including those with recent thoracic surgery and transthoracic needle biopsy.

Flight Diversions Due to Onboard Medical Emergencies on an International Commercial Airline

Each year, close to 2 billion passengers travel on commercial airlines. In-flight medical events result in suboptimal care due to a variety of factors. Flight diversions due to medical emergencies carry a significant financial and legal cost. The purpose of this study was to determine the causes of in-flight medical diversions from Air Canada. This was a review of in-flight medical emergencies from 2004-2008. Both telemedicine and Air Canada databases were crossreferenced to capture all incidents. Presenting complaints were categorized by systems. Descriptive statistics were used to analyze the data. Over the 5 yr, there were 220 diversions, of which 91 (41.4%) of the decisions were made by pilots or onboard medical personnel. During this period there were 5386 telemedicine contacts with ground support providers, who on average recommended 2.4 diversions per 100 calls. The rate for diversions almost doubled from 2006 to 2007, with a sharp drop in telemedicine contacts during the same period. The four most common categories resulting in diversions were cardiac (58 diversions, 26.4%), neurological (43 diversions, 19.5%), gastrointestinal (GI) (25 diversions, 11.4%), and syncope (22 diversions, 10.0%). Only 6.8% of all diversions were due to cardiac arrest. Medical conditions most commonly leading to diversions were cardiac, neurological, gastrointestinal, and syncope. Our study showed that a decrease in telemedicine contact during this period was accompanied by an increase in diversions, while increased pre-screening of passengers did not prove effective in decreasing diversion rates.

Predictors of Flight Diversions and Deaths for In-flight Medical Emergencies in Commercial Aviation

In-flight medical emergencies are clinically challenging and may result in aircraft diversions, which are costly and inconvenient, or in-flight deaths. We provide an updated description of in-flight medical emergencies and systematically examine predictors of medical flight diversions and in-flight deaths.

Surgical and medical emergencies on board European aircraft: a retrospective study of 10189 cases

IntroductionIn-flight medical and surgical emergencies (IMEs) onboard commercial aircrafts occur quite commonly. However, little epidemiological research exists concerning these incidents.MethodsThirty-two European airlines were asked to provide anonymous data on medical flight reports of IMEs for the years 2002 to 2007. The total number of incidents was correlated to revenue passenger kilometers (rpk). Additionally, on-board births and deaths, flight diversions, flight routes (continental/intercontinental) and involvement of a physician or medical professional in providing therapy were analysed.ResultsOnly four airlines, of which two participated in this study, were able to provide the necessary data. A total of 10,189 cases of IMEs were analysed. Syncope was the most common medical condition reported (5307 cases, 53.5%) followed by gastrointestinal disorders (926 cases, 8.9%) and cardiac conditions (509 cases, 4.9%). The most common surgical conditions were thrombosis (47 cases, 0.5%) and appendicitis (27 cases, 0.25%). In 2.8% of all IMEs, an aircraft diversion was performed. In 86% of cases, a physician or medical professional was involved in providing therapy. A mean (standard deviation) of 14 (+/- 2.3, 10.8 to 16.6 interquartile range) IMEs per billion rpk was calculated.ConclusionsThe study demonstrates that although aviation is regulated by a variety of national and international laws, standardised documentation of IMEs is inadequate and needs further development.

Protecting the functionality of airports during disaster responses—Natural disasters, accidents, and pandemics

Airports are important assets during disaster response. Traditional roles as command posts, shelters, temporary hospitals, and alternative communication hubs were filled by airports after Hurricane Katrina and for 9/11 flight diversions. The basic thesis of this article is that airports need special measures to preserve functionality (continuity of business) during response and recovery. The second thesis is that sound emergency management measures should be built into airports as a type of mitigation. This article applies qualitative analysis to historical case studies, plans, documents, and scenarios for use of airports during disasters. It focuses on policy, procedural, organizational, and operational measures to protect the functionality during responses.

Air Travel and Cardiovascular Disease

J Travel Med 2004; 11:243–250. Almost two billion passengers undertake international and domestic air travel each year.1,2 As the population ages and our ability to care for patients with cardiac disease improves, an increasing number of people with cardiovascular disease will be traveling long distances.Many such travelers have had pacemakers or automatic defibrillators implanted,have had recent revascularization,or have had surgery which might predispose to deep venous thrombosis (DVT). Recent data drawn from several major US carriers between 1996 and 1997 show 15 deaths among approximately 1.4 million passengers.3 Cardiac events account for the greatest percentage of flight diversions and appear to represent the major cause of in-flight death.3,4 As more patients with severe cardiovascular disease travel, on-board cardiac events might be expected to increase. A general overview with contraindications to air travel and recommendations for the patient with cardiovascular disease is presented in Tables 1 and 2. We will review the pathophysiology and delineate the risk for patients with cardiovascular disease of sudden death, DVT, and ischemia/infarction when they travel by air. On 12 June 2001,the Federal Aviation Administration (FAA) issued a final ruling mandating that passengercarrying aircraft of more than 7,500-lb maximum payload capacity with at least one flight attendant carry at least one automated external defibrillator (AED) and an enhanced emergency medical kit (Table 3).All flight attendants will be required to receive initial and recurrent training on AED usage and in cardiopulmonary resuscitation (CPR). The rule becomes effective on 12 April 2004. Page et al. extrapolated from the data accumulated regarding AED use by one major US airline, and suggested that the widespread availability of AEDs on commercial airlines might prevent up to 93 in-flight deaths from ventricular fibrillation each year worldwide.5 Longterm survival rates in such patients range from 26% to 40%,which compares favorably with the 2% to 5% longterm survival rates often quoted for out-of-hospital arrests.6,7

Pediatric Emergencies on a US-Based Commercial Airline

The purpose of this investigation was to determine the incidence and character of pediatric emergencies on a US-based commercial airline and to evaluate current in-flight medical kits. In-flight consultations to a major US airline by a member of our staff are recorded in an institutional database. In this observational retrospective review, the database was queried for consultations for all passengers up to 18 years old between January 1, 1995, and December 31, 2002. Consultations were reviewed for type of emergency, use of the medical kit, and unscheduled landings. Two hundred twenty-two pediatric consultations were identified, representing 1 pediatric call per 20,775 flights. The mean age of patients was 6.8 years. Fifty-three emergencies were preflight calls, and 169 were in-flight pediatric consultations. The most common in-flight consultations concerned infectious disease (45 calls, 27%), neurological (25 calls, 15%), and respiratory tract (22 calls, 13%) emergencies. The emergency medical kit was used for 60 emergencies. Nineteen consultations (11%) resulted in flight diversions (1/240,000 flights), most commonly because of in-flight neurological (9) and respiratory tract (5) emergencies. International flights had a higher incidence than domestic flights of consultations and diversions for pediatric emergencies. The most common in-flight pediatric emergencies involved infectious diseases and neurological and respiratory tract problems. Emergency medical kits should be expanded to include pediatric medications.