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The true costs of heavier passengers: Part one
In recent years much attention from the world’s media, particularly in Europe and the USA, has been placed upon the trend in people getting physically bigger and the ensuing obesity epidemic that is occurring in many countries across the globe. The public health issues that surround such trends are far-reaching, and arguably growth in the size and weight of individuals in many countries is increasingly affecting the general public’s everyday lives. We need to assess and form a comprehensive understanding of how changes in the physical size of air travellers are impacting the commercial airlines of today.
The implications arising from the carriage of larger air travellers is an issue that has, and continues to be discussed at the highest of levels. In 2000 the UK House of Lords Select Committee on Science and Technology published a report recommending the urgent completion of research into UK aircraft seat dimensions in the light of the current sizes of air travellers. Four years later an American report estimated that the obesity epidemic occurring in the USA was forcing US airlines to burn an additional 350 million gallons of fuel each year. Ultimately the core product delivered by any commercial airline is the transportation of people from one place to another. Subsequently, as a service provider, airlines are required to change the product they offer in order to avoid any negative effects imposed from changes in their customers’ attitudes and characteristics.
Undoubtedly the media, particularly in the western world, has communicated obesity, weight gain and associated health implications with increasing prevalence in recent years. Whilst it is suggested that the far-reaching issue of obesity in today’s world is one of such prominence that it has been discussed at a high level within most airlines, corresponding literature and academic studies tackling this very point are somewhat sparse. It is apparent that, regardless of the presence of weight gain and trends in people getting physically bigger, the larger-sized passenger presents airlines of today with a real management issue. To date many of these issues have not been approached nor documented within academic literature and therefore much of this review is based upon circumstantial evidence from other public media sources including press articles, court hearings and electronic resources.
There is little doubt that obesity has and continues to be a prominent issue fuelled by constant media attention within European and American societies in particular. Despite continued and evermore prevalent documentation and press attention surrounding the health implications of obesity, it is estimated that 1.1 billion people are now classified as overweight, 300 million of which are classified as obese, and is subsequently regarded as a health issue of global ‘epidemic’ proportions. The proportion of overweight adult citizens in many European countries is in excess of 50%, with even higher prevalence rates in regions including the US, who are subject to the world’s highest prevalence of ‘morbid obesity’.
Economic impact on airlines
In 2004 a report published in the US grabbed the attention of the world’s media by estimating the economic cost of the nation’s obesity epidemic incurred by domestic airlines. Dannenberg et al (2004) estimated that the average individual weight gain of 4.6kg (10 lbs) per US citizen through the 1990s required domestic carriers to consume an additional 350 million gallons (approximately 1,084 million kg) of jet fuel. The article estimated that for the year 2000 this would translate to a total cost of US$275 million (GB£137.9 million) and the subsequent emission of an additional 317.5 million tonnes of CO2, along with additional pollutants including NO2.
If it was assumed that on average, following the year 2000, the US population had not gained any more weight and the fuel consumption of domestic airlines was also unchanged, the cost of this additional fuel would correspond to a cost today of US$637 million or GB£319.5 million, based on a jet fuel price of US$1.82 per gallon. It is, however, very likely that the average weight of American individuals will have increased in this time and furthermore in the reported period of 2005, domestic air services accounted for a total of 6,704 million aircraft miles (Bureau of Transportation Statistics 2007), an increase of over 1,000 million miles from the period on which this study was based upon.
Comfort and seating
The very issue of western populations being subject to increasing rates of obesity gives rise to an extremely important element affecting airlines serving within and between such regions. That element is the capability of airlines to be able to physically accommodate all passengers within their aircraft in a comfortable and safe way.
Every airline endeavours to simultaneously minimise its unit costs and maximise its unit revenues to maximise the profitability of each flight it operates. In the aviation industry this process integrates a range of variables, but perhaps fundamental to this is often an airline’s ability to fit as many passengers on each of its flights as possible within the confines of operational, legislative and safety limitations. One of the best-documented examples of this aim is that of traditional European charter airlines that historically, on short-haul routes, offered single-class cabin configurations and small seat pitches to maximise profits. In more recent times this strategy has been developed further by many airlines through the reduction of seat widths and seat backs to gain in some cases just one extra row of seats on an aircraft.
Seat pitch has long been a prominent point of discussion within the industry, from general public complaints of insufficient legroom, to airlines marketing their seat pitches in an attempt to establish product differentiation. The importance of travelling in comfort is now valued so highly by the travelling public that entire internet websites have been developed, wholly dedicated to providing airline and aircraft-specific information to passengers as to which seats offer maximum space and comfort. Increasingly, however, emphasis is also being placed upon airline seat widths and the general ability of passengers being physically capable of fitting in a single aircraft seat. Despite trends in passengers researching more extensively how to get the most comfortable flight out of their purchase, it is still very apparent that the weight gain of westerners is compromising this ability.
Differential pricing policies
Inevitably airlines have had to react to the prominent issue that it is becoming a common occurrence that some passengers’ physical dimensions exceed those of the design parameters of their aircraft seats. This has been particularly the case in the US, where low-cost carrier Southwest Airlines has generated huge media attention through its ‘passengers of size’ policy by insisting that if a passenger is unable to fit between the armrests of a single seat then a second seat must be purchased. Although this policy was first introduced in 1980, the airline began strictly enforcing it in June 2002 (22 years later) after stating that nine out of ten complaint letters the airline received were from disgruntled passengers who had been seated next to larger passengers encroaching upon adjacent seating.
Southwest Airlines has defended this policy and reiterated to the public that it is a matter of economics, with larger sized passengers who consume more than one unit of their product – in this case a seat – being required to pay for what they consume. Furthermore, Southwest maintains that, following the strict implementation of its two-seat policy, it has received very few complaint letters from upset passengers subjected to uncomfortable journeys due to being seated next to larger passengers, and that all passengers now have a clear understanding of the airline’s policy, ensuring they travel in a comfortable and safe manner.
It has been suggested that from an airline’s perspective such a policy represents good economical business sense, with passengers paying for what they consume and furthermore ensuring safety and comfort for all travellers. Conversely, it is argued that from the travelling public’s viewpoint, a differential pricing policy not only represents price discrimination, but also inequality in its non-uniform application throughout the industry.
The subject of so-called ‘differential pricing’ as exemplified by Southwest Airlines’ existing policy, has sparked mass media attention and debate within the general public. In particular, Southwest has been subject to accusations of discrimination, and in 2002 the American Obesity Association filed an official complaint against the airline on these very grounds.
The dissatisfaction vocalised by various organisations and groups at Southwest’s policy in the US brought about a think tank in 2002 hosted by the National Association to Advance Fat Acceptance (NAAFA) titled ‘Airlines and Fat Passengers’. At the think tank, NAAFA members were given the opportunity to question various carriers including Southwest Airlines, American Airlines and Continental Airlines. Whilst many issues were addressed over the course of the conference the prominent themes that underlined the discussions included criticism of manufacturers’ seat designs and, perhaps most importantly, that the practise of differential pricing constitutes discrimination against obese people.
Furthermore it was argued that airlines are required to accommodate other groups of people with special needs, such as wheelchair users and the visually impaired, at no extra cost. This element gives rise to the all-important question as to whether obesity should be considered a disability. At the think tank the airlines categorically answered this question with a resounding no, which is an opinion that has long been debated within law courts both in Europe and North America.
Obesity and weight-based discrimination cases and hearings are not altogether new to the aviation industry. From as early as the 1970s there have been several high-profile cases in which airline flight attendants have taken their employers to court on the basis of weight discrimination. Surprisingly in many of these cases judicial systems have upheld airlines’ weight and height programmes on several grounds and rarely found in favour of the discriminated individual(s).
In 1977 American carriers Eastern Air Lines and Delta Air Lines were both taken to court by ex-employees on the grounds of weight-based discrimination. In both cases the courts found that the weight requirements of the airlines did not constitute discrimination based upon weight not being an immutable characteristic, that is to say an individual is capable of changing their weight unlike the conditions that surround a discrimination case involving gender or terminal disabilities. More recently, in 1991, Delta Airlines were again involved in a court battle over weight-based discrimination of employees brought against them by the New York State Division of Human Rights, with the courts again finding insufficient grounds to consider weight requirements as a discriminatory practice.
As exemplified by NAAFA, weight-based discrimination in civil aviation reaches far beyond employees within the industry. In recent years a number of disgruntled passengers have brought numerous complaints and prosecutions forward to regulatory authorities, courts and the airlines themselves on the grounds of unfair treatment and discrimination relating to their physical size.
In 1997 a Canadian individual lodged a formal complaint to the Canadian Transport Agency (CTA) against Air Canada on the grounds that the airline did not accommodate the seating requirements of an obese customer after the airline forced her to purchase one and a half seats. The basis of this particular case was centred on the individual’s perception that her obesity should be considered a disability and should have, therefore, been accommodated by the airline subject to no additional cost. Following the complaint, an official tribunal was heard by the CTA, which also conducted a full examination of the issues of air transportation for obese passengers and its constitution as a disability. In 2001 the CTA announced its official ruling that obesity is not a disability, and furthermore that there was little evidence to suggest that obese passengers experience restrictions in the Canadian transport network.
Although on this occasion the ruling was in favour of the airline, the CTA stated that evidence suggested that some obese individuals might in fact be considered disabled and as such future cases of a similar nature would be assessed on an individual basis. Similar situations have occurred in the US, with courts failing to find size-based pricing policies as qualifying under discriminatory practices, including policy-setter Southwest Airlines.
Whilst literature suggests that legal cases of weight-based discrimination and differential pricing are particularly prominent in North America it is by no means an issue exclusive to this particular part of the world. In December 2006, a French writer threatened to sue Air France after being forced to purchase a second seat on a flight from New Delhi. After declaring he weighed 160kg, airline staff measured the passenger at check in and deemed that his size meant he would have to purchase a second seat. Whilst the French flag-carrier argues that it operates a clear policy requesting large passengers to purchase a second seat when required, the outcome of this case is yet to be decided. This does not represent the only occasion in which Air France’s two seat policy has caused major upset amongst its passengers. In 1999 an almost identical situation occurred when a French traveller was denied boarding his flight to Beijing unless he purchased a second seat, after which the traveller threatened to sue the airline and take it to the European Court of Human Rights on the grounds of discrimination.
Similar cases have also featured in media coverage throughout other parts of the world, emphasising that this type of issue is not necessarily confined to western countries. Dragonair was subject to an official human rights violation and discrimination complaint lodged against it with the Consumers’ Foundation of Taiwan. In this case a customer had pre-informed the Hong Kong-based airline of their size and the requirement of a second seat when making their reservation. Although accepting the reservation Dragonair contacted the individual the day prior to their flight and informed them that they would not be permitted to fly on the basis of safety concerns.
As detailed above, Southwest Airlines began enforcing its ‘passengers of size’ policy as a direct reaction to the high frequency of complaints from unhappy passengers who had been seated next to large passengers on its services. This pays testament to the importance of airlines ensuring safety and comfort for all passengers. If an individual is incapable of fitting into an aircraft seat then it is likely that they will encroach upon adjacent seating if and when a second seat is not acquired, and it is this occurrence that has provided perhaps the best documented legal case relating to larger-bodied passengers in the UK. In 2002 Virgin Atlantic was forced to award a 63-year-old passenger compensation amounting to GB£13,000 after she had suffered a blood clot, leg muscle tear and sciatica as a direct subsequence of being sat next to and subsequently ‘crushed’ by a larger passenger who encroached her seat on an 11-hour flight to Los Angeles.
Air travel and disabled passengers
Undoubtedly the issue of physically larger people is something that airlines the world over have had to deal with at a legislative level, with some forced to defend their policies and practices regularly. In researching this very aspect and assessing the documented cases above, there exists a clear underlying and common issue that is yet to be uniformly resolved in many countries. That is the question: ‘does obesity constitute a disability?’
Regulation No 1107/2006, which took effect on 26th July 2007, governs the legal requirements of all airlines operating from, to and within the EU with respect to the carriage of disabled persons and passengers with reduced mobility. As well as requiring the provision of a seamless journey experience from airport to airport, the new regulation entirely prohibits discrimination against passengers based upon their disability or reduced mobility. Similarly in the US, the Department of Transportation’s ‘Non Discrimination on the Basis of Disability in Air Travel’ in the Air Carrier Access Act prohibits discrimination on the basis of disability.
In specific cases, such as those described above, aviation bodies including Southwest Airlines and the Canadian Transport Agency clearly state that in the majority of cases, if not all, obesity is not considered a disability and thus such legislation is not applicable in weight-related discrimination cases. Whilst in some circumstances this may be deemed as not necessarily true, if and when obesity is ever considered a disability or incorporated as a condition under reduced mobility it is unlikely that airlines will still have the ability to exercise differential pricing policies including compulsory second-seat purchasing.
This could potentially lead to the development of two situations. Firstly, airlines may be forced to provide passengers of size with extra seats at no extra cost. Secondly, airlines may altogether refuse the carriage of larger passengers, as both EU and US legislation specifies that this right may be granted under situations whereby the safety of a flight may be compromised. Southwest Airlines has repeatedly emphasised that in no way is its policy a ‘money-making’ tool and that on its flights only six seats account for the profit margin. Indeed it is widely accepted that the operating and profit margins of airlines in today’s highly competitive and saturated aviation market are generally very slight, regardless of the various business models being operated. Subsequently it is possible that airlines may exercise rights to refuse carriage on safety grounds in order to avoid any potential profit loss associated with a second seat provision at no extra charge to a customer.
A fundamental aspect that must not be forgotten in addressing all of the points above is that all airlines are operating within a service industry and subsequently satisfying customers as far as possible is integral to their success. The very issue of larger passengers is clearly something that has both challenged and questioned this relationship, whether it be a passenger legally pursuing discrimination claims, or an individual who is disgruntled following an uncomfortable journey next to a fellow passenger incapable of fitting into a single seat.
One of the major issues surrounding larger passengers is that of applying equity. This very point was published by a UK broadsheet newspaper in December 2006, when a member of the public wrote to The Daily Telegraph’s Travel Supplement. In his letter, a Mr Clarke questioned how it was that, as a 65kg passenger, he might have to pay excess baggage rates if just a few kilograms over an airline’s baggage limit, whilst a passenger in excess of 100kg would be given the same baggage allowance? If for example an airline’s baggage policy was limited to 20kg then a 100kg passenger with 20kg of baggage would not incur any excess charges, whilst a 65kg passenger with 22kg of baggage may incur excess charges, despite the smaller passenger’s combined passenger and baggage weight being 43kg lighter than the heavier passenger’s corresponding total weight.
In 2002, following Virgin Atlantic’s GB£13,000 settlement with the ‘crushed’ passenger, the BBC ran an online open forum, inviting members of the public to share their thoughts and opinions on: ‘should obese passengers pay extra?’ In total more than 60 opinions were documented under the forum, which can be summarised as:
• It is unfair that obese passengers are treated any differently or discriminated against
• The size of aircraft seats are inadequate to accommodate the travelling public in general
• If an individual’s size affects the comfort of fellow passengers then they should have to pay accordingly, whether through purchasing a second seat or by upgrading to a non-economy class seat (a comparison is cited to the fact that smoking is now prohibited on nearly all flights to protect the health and comfort of the majority of non-smoking passengers)
• Increasing aircraft seat sizes will reduce the capacity of aircraft and push up the cost of travel
• Charges should be applied to the combined weight of both a passenger and their baggage
Internet-based airline directory Airlines.ws ran a similar poll in 2005 asking readers to vote on the question: “Should overweight passengers pay more for their airline tickets?” Whilst the results of the survey do not document how many votes were cast in total, the results showed 55% of respondents being in favour of charging more, with a corresponding 45% portion voting against the question.
Differential pricing policies based on a passenger’s physical size is a subject that is clearly met with mixed reactions from the general public. If representative of the entire travelling public this would suggest airlines are in a somewhat helpless position in which it is likely there will always be a proportion of customers who disagree with their policy. With such an evidential divide perhaps one possible solution may lay in the design of aircraft seating whereby larger passengers may be accommodated, at a likely subsequent expense that will be incurred by all travellers, thus ensuring the absence of any discriminatory-based claims. However, in a study carried out in 2004 by Lee and Luengo-Prado, little evidence was found that the majority of the travelling public would be willing to pay for extra legroom. Arguably, therefore, it is unlikely that the same travelling public would be willing to pay for overall roomier seats in the probable scenario that this would result in higher travelling costs.
The role of regulations
In Europe and the US there exist two principal types of regulation related to the issue of passenger size and weight. The first is that of regulations governing the weight of passengers and their baggage for use in aircraft loading and balance control. The second is that of regulation regarding specifications of seating within aircraft.
The FAA stated in 2007 that “Excessive weight reduces the efficiency of an aircraft and the safety margin available if an emergency condition should arise”.
The accurate valuation of an aircraft’s weight increases in importance as the size of aircraft decreases. Modern aircraft are designed with strict weight and load restrictions and very often if an aircraft were filled with its maximum capacity of passengers, baggage and fuel it would no longer lie within its prescribed operating weight limitations.
JAR OPS-1 (Joint Aviation Requirement) Subpart J, as published by the JAA (Joint Aviation Authorities) and EASA (European Aviation Safety Agency), regulates the mass and balance of commercial European registered aircraft (EASA/JAA 2007).
JAR OPS-1 requires that operators ensure and monitor that all aircraft’s loading, mass and centre of gravity (CG) are calculated and remain within the published limitations of each aircraft. The mass of all operating items, fuel, crew, passengers, baggage and freight must be documented and the cumulative effect on the aircraft’s CG calculated. Furthermore the fuel requirements of an aircraft are a function of its weight and the length of the flight it is operating. Therefore correct determination of an aircraft’s weight is fundamental in the flight planning and fuel provisioning processes carried out by airlines.
Standard passenger weights
Important from the perspective of this research is the calculation of the weight of passengers and their baggage. JAR OPS-1 specifies that operators must ‘compute the mass of passengers and checked baggage’ through the use of either standard weight values prescribed within the regulation or by the actual weighing of passengers.
Standard passenger mass values are specified based on a number of variables including aircraft size, gender and the type of flight, as summarised in Table 3.1 below. The standard weights include 6kg of ‘carry-on’ luggage and take into account adults that may be carrying and seated with an infant (defined as two years of age or younger).
Table 3.1: JAR OPS-1 prescribed standard passenger weights
The impact of incorrectly calculating an aircraft’s load increases in significance as the size of the aircraft decreases and thus the adverse effects of underestimating loads are likely to affect smaller piston aircraft much more significantly than large jet-powered aircraft. This is emphasised in the JAR OPS-1 prescribed mass values that exhibit an increasing overestimation of passenger weight as the size of the aircraft (the number of passengers it seats) decreases. The overestimation of weights therefore offers a level of assurance to operators by ensuring that the actual weight of passengers onboard (and their subsequent cumulative weight) is most likely to be less than those of standard values.
Standard weight values for checked baggage are also provided under JAR OPS-1, dependant upon the length of flight being operated. However, it is common practice for the majority of commercial airlines to weigh checked baggage in relation to their respective baggage policies.
Airline weight surveys
JAR OPS-1 permits operators to establish their own standard passenger weight values for use in aircraft loading, balance and fuel calculations. Operators choosing to do so are required to carry out passenger weight surveys, the methodology of which is also strictly governed by JAR OPS-1.
The degree and extent to which this is carried out varies between airlines. In March 2007, Ryanair asked passengers at Dublin Airport to be weighed in order to ensure that the loading of their aircraft was accurately known and within satisfactory limits. As an extremely cost-conscious airline it is understandable that Ryanair accurately establishes payloads and subsequent fuel requirements in an endeavour to help minimise and control the operating costs of each flight. Interviews conducted with British Airways’ operations department for the purpose of this research highlighted that there exists a natural variation in average passenger weights between different long- and medium-haul sectors. For example, if the average passenger weight on sectors between the UK and the US were compared to those of sectors between the UK and the Far East it is likely that a noticeable difference will exist, with a subsequent variation in the fuel requirements of aircraft operating these routes. Both examples demonstrate how it may be advantageous for an airline to carry out passenger weight surveys as opposed to using the prescribed values offered within JAR OPS-1.
JAR OPS-1 requires that airlines choosing to conduct passenger and baggage weight surveys do so using random sampling techniques and ensure that the survey is carried out immediately prior to passengers boarding an aircraft. Sample size is set at a minimum of 2,000 (for aircraft with a capacity of 40 seats or more) or a minimum of 50-times the size of an aircraft’s capacity (for aircraft with 39 or fewer seats). Operators of aircraft with 19 or fewer seats are required to add extra notional weights to their derived average passenger weights, thus re-emphasising the relative importance of over-estimating loads in the operation of smaller aircraft.
Operators of aircraft with 30 or more seats are able to combine survey averages of males and females to output a standard revised ‘adult’ weight, based upon a male to female ratio of 4:1. Again this ratio overestimates the proportion of males on most European flights in order to help further ensure against any potential mass and loading underestimation during operations. Regulatory bodies must approve the measurement, calculation and use of survey-derived passenger weights and require airlines to revise these weights at least every five years.
The regulation of passenger weight in relation to aircraft loading, balance and fuel provisioning in the US is governed by the Department of Transportation and the FAA. Advisory Circular 120-27E (FAA 2005) details the latest edition of these regulations and the four methods by which an operator may establish average passenger weights.
Standard average weights
AC120 details standard passenger weights for use by commercial airlines, although unlike its European equivalent the regulation stipulates that recommended application of these weights is only to be used for aircraft seating 30 or more passengers.
FAA standard passenger weights (Table 3.2 below) are derived from national health survey data based on the assumption that the weight of the general public is representative of air travellers. The standard weights are segregated by time of year in order to account for heavier clothing during winter months and an airline’s specific policy regarding the allowance of carry-on hand luggage.
Table 3.2: AC120-27E prescribed standard passenger weights
The table above shows that US standard adult passenger weights are 4kg or 2kg higher (dependant on time of year) than those prescribed in Europe. As in JAR OPS-1, AC120 also prescribes standard weight values for checked baggage, although it is similarly likely that most airlines under FAA regulation will weigh all checked baggage in conjunction with their individual baggage allowance policies.
Under the approval of the FAA, operators may choose to establish passenger and baggage weights through the undertaking of a survey. Using random sampling techniques an operator is required to survey the weights of adults, children and checked baggage with minimum sample sizes of 2,700, 2,700 and 1,400, respectively. Operators are required to revalidate survey-derived standard weights or switch to prescribed standard weights (as shown above) 36 months subsequent from the survey date.
Further to its standard passenger weights the FAA recommends the use of prescribed ‘segmented weights’ for all aircraft with passenger capacities greater than five. Segmented weights derive a standard passenger weight to be used by airlines based upon the proportion of male and female passengers on an aircraft. Table 3.3 shows an example of the segmented weights for aircraft classified as ‘very heavy’ (seating capacity greater than 53).
Table 3.3 Segmented standard passenger weights for aircraft seating 54+ passengers
The use of actual weights provides the final means by which US airlines may obtain the weight of their passengers, recommended particularly in the operation of smaller aircraft more susceptible to the impact of underestimating total load values. Determination of actual weight is recommended by one of two methods. Firstly by the actual weighing of all passengers with the use of approved apparatus, and secondly by asking each passenger their weight and adding a further 5kg to each volunteered weight to ensure against underestimated values.
The cost of getting it wrong
Whilst there exists a clear level of consistency between US and European legislation governing the designation of weight to each passenger, it is fundamental to address the potential impact that miscalculating the weight of passengers may impose upon airlines.
Ratio of male to female passengers
In January 2003 Air Midwest flight 5481 crashed shortly after take off, killing all persons onboard. The airline’s weight and balance programme, as well as the FAA’s prescribed standard weight values, were considered major contributory factors to the Beechcraft 1900D accident, initiating a program to revise the FAA’s prescribed passenger weights. Standard values designated for 10- to 19-seat aircraft at the time were found to have underestimated the weight of each passenger by 9.5kg and each baggage item by 3kg.
Exactly one year later, Canadian-based Georgian Express flight 126 crashed north west of Pelee Island. The Cessna 208B Grand Caravan struck a nearby ice-covered lake, killing all persons on board. Investigations yielded that the aircraft weight exceeded its Maximum Takeoff Weight (MTOW) by more than 15%, with reports highlighting the use of standard passenger weights had underestimated the actual total weight of passengers by 257kg.
In both of the above cases the aircraft type was relatively small in size, highlighting once again the increased importance of accurate weight determination for smaller aircraft. However, this is an issue that may affect larger aircraft, despite their better capability of overcoming load miscalculations. Indeed, in the UK alone, investigations surrounding a range of aircraft sizes relating to this issue have been launched, including two separate tail strikes of Loganair’s Saab 340 fleet and Virgin Atlantic allowing the deployment of very large passenger aircraft, on more than one occasion, with weight and balance errors.
The overall magnitude of aircraft incidents arising from weight and loading miscalculations was researched by NLR (Dutch National Aerospace Laboratory) and presented at the Flight Safety Foundation seminar held in the Netherlands in March 2007. Studying accidents over the past three and a half decades, NLR found that a total of 82 of these involved miscalculations of weight, loading and balance as contributory factors. Furthermore of the 82 accidents, 61% were passenger flights with cargo flights representing the other 39%.
Given, therefore, that it can be clearly seen just how important the weight of passengers and their possessions is in air travel, it is somewhat surprising that there has been no revision of the standard JAR OPS-1 values since their implementation in 1991. Whilst ultimately it is a carrier’s responsibility to ensure the loading of each aircraft is accurately known prior to being dispatched, it should be argued that standard passenger weights included in regulations, from a safety viewpoint, should be assumed as being used by operators under its regulatory jurisdiction. The air accidents described above illustrate just how catastrophic failure to revise standard weights can be.
Regulation of aircraft seating
One of the greatest issues that larger passengers present to airlines relates to the increasing problem of the ability to fit into a single seat in a safe and comfortable manner. Currently, there exists only one example of regulation relating to this issue in Europe and the US.
‘Airworthiness Notice 64’ (AN64) was issued by the UK CAA in 1989. Titled ‘Minimum Space for Seated Passengers’, AN64 provided mandatory action advice applicable to all UK-registered aircraft exceeding 5,700kg Maximum Takeoff Weight Authorised (MTWA) and configured to carry 20 or more passengers. Setting out dimensional minima for aircraft seating, AN64 was established to minimise the effect of small seat pitches found on commercial aircraft at the time, with the objective of regulating how and where a passenger may strike the seat in front, the physical ability of passengers to occupy a seat, and the ease for a passenger to leave their seat (quickly if in an emergency) and enter the cabin’s aisle(s).
In 2001 the UK CAA funded and published the ‘Anthropometric Study to Update Minimum Aircraft Seating Standards’. Originally initiated by the JAA, the purpose of this research was predominantly to assess if there existed a requirement for the Europe-wide regulation of aircraft seating in the light of growing body trends, high-density seating, and increases in long duration flights. Although, to date, no such regulation has been implemented nor drafted, the study itself yielded some very important research findings.
The 2001 study very much focussed upon the safety aspects of seating standards, with the objective that aircraft seats should be designed so as to ensure passengers are able to exit both their seats and the aircraft quickly in the event of an emergency. In reviewing the existing UK regulation, the study found that the dimension minima established by AN64 would be inadequate to currently seat at least one out of every four European passengers. In particular, the study raised concerns over seat widths and the distance between the inside edges of armrests. A survey sampling various airlines’ seating found that seats were ‘totally inadequate to accommodate larger-bodied passengers’. Furthermore the report highlighted that not only does this result in the discomfort of the larger passenger, but also those of neighbouring passengers. The report included new recommended minimum dimensions that should be adopted by new regulations, including that of seat width, a more detailed analysis of which is carried out below.
Body mass trends
When assessing the impact and implications of historic changes and trends in weight and obesity on the civil aviation industry, one important consideration that must be accounted for is the global nature of the industry. That is to say the magnitude and variability of such changes that have taken place will substantially vary between different regions of the world. This is illustrated in Table 4.1 below, which shows the mean values for both height and weight across a sample of countries. Whilst these values are now dated, combined they provide a snapshot in time to demonstrate the variation present between populations at any one time.
Table 4.1: Global variation of physical attributes
In this example alone, from the countries selected there is a range in mean height of 12.7cm and a corresponding value of 17.8kg in mean weight. However, such information is only indicative of the physical variation between different countries at any one time. Figure 4.1, below, furthers the concept of variation between different populations and simultaneously illustrates the prevalence of overweight and obese individuals within different countries, providing an indication of the variation of historic body weight changes that have occurred within each respective nation. This diversity suggests that the issue surrounding people becoming physically bigger is likely to be one that is and has been felt much more by some nations than others, particularly within western countries such as North America.
Figure 4.1: International variation in the prevalence of normal, overweight and obese individuals
No weight data exists specific to air travellers other than those acquired by an airline’s own weight survey programme, the results of which are unlikely to be released into the public domain. National surveys and anthropometric databases however, accurately assure that data is statistically representative of an entire population and therefore it is unlikely that discrepancies in comparing historic data will arise from differences between the respective samples taken. It may be argued that analysing national data may not necessarily be representative of the travelling public or those members of a population who use air travel. However, in a report carried out by the UK’s Food Standards Agency it was found that nutrition, access to food and cooking skills do not differ significantly between income brackets. This therefore suggests that even if air travellers are higher income earners than those people who do not travel by air, there is no evidence to suggest that their dietary trends and thus body weight are likely to be any different from the general public and therefore use of national based data is fully justified.
Furthermore, research suggests that the specific issues concerning larger passengers and air travel have risen and only affected the airline industry in comparatively recent times and most noticeably in the western world. During this time both the European and US markets have been subject to the deregulation of air services, and subsequent increases in air travellers and aviation traffic have ensued. Both the European and North American aviation markets are now highly competitive and saturated, and as such air travel is now relatively inexpensive and increasingly accessible to more and more people. Therefore it may be argued that in a deregulated environment national data is likely to represent a closer approximation to the corresponding values of the air-travelling public than in a more expensive heavily regulated market.
Body weight data
The US NHANES survey represents one of the world’s only publicly available sources of national-based medical data, detailing national body weight trends. Undoubtedly it has been shown that the issue of physically larger passengers has, to date, been most felt by North American carriers and as such evaluation of this data offers an invaluable source of forming an initial understanding of the magnitude of the core health issue that lies behind these problems.
Figure 4.2, below, summarises the mean body weight of the US population over the past four decades. The data is separated into the four reporting periods of the health survey up to 2002.
Figure 4.2: Historic body weight of US adults
The data indicates that between 1960 and 2002 the average weight of both male and female adults increased by more than 10kg, with latest obtainable figures suggesting that average weights currently stand at 86.1kg and 74.0kg for men and women, respectively. For both genders the largest growth has occurred between 1988-1994 and 1999-2002, over which time the male population gained an average of 3.8kg with a respective female growth of 4.5kg.
Whilst their is no equivalent documenting of national body weight data amongst UK medical sources, there exists further medical indictors whereby trends in body weight may be identified and analysed. Whilst these indicators do not provide decisive physical values of weight, they do provide a strong indication of historic trends.
Body mass index (BMI) is the measure commonly used in the medical industry, calculated by dividing an individual’s weight by the square of their height. Any change in this value is therefore directly indicative of a change in body weight. Subsequently, by analysing the changes of national BMI values, as collected in both UK and US health surveys, over time it is possible to gain an appreciation of the magnitude of historic weight changes.
BMI values fall within one of three categories indicating whether an individual is of a healthy weight (BMI<24.9), overweight (25<BMI<29.9) or obese (BMI>30). Figure 4.3, below, shows the historic prevalence of these categories amongst the US adult population. The chart shows that from the period 1960 to 1980 the proportion of healthy-weight individuals in the US remained relatively steady, although during this time there was a slight increase in the proportion of obese individuals. Most noticeable is the downward trend that occurred subsequent to this period during which the proportion of overweight and obese individuals increased from 47% to 66%. This trend is corroborative with the mean body weight data obtained from the same survey, as shown in Figure 4.2, illustrating a continuous increase in the average weight of US citizens with an acceleration of this increase occurring over the past 25 years.
Figure 4.3: Historic prevalence of BMI categories amongst US adult population
A corresponding prevalence chart has been compiled using UK health data from 1980 to 2004, as shown in Figure 4.4 below. Similar to the US data, an obvious increase in the proportion of the UK’s population who are deemed as overweight or obese has been exhibited over this period. The proportion of healthy weight individuals has fallen on average 0.94% annually, indicating that consistently UK individuals are getting physically bigger and heavier each year. Comparison of the latest statistics suggests that the UK has a smaller proportion of obese individuals than the US, whilst the proportion of healthy-weight individuals is of a similar size for both countries. Furthermore the data indicates that the proportion of healthy weight individuals in the UK has fallen at a similar rate to that of the US over the 24 year period considered.
Figure 4.4: Historic prevalence of BMI categories amongst UK adult population
Figure 4.5, below, further emphasises the trend experienced in the UK and illustrates the average BMI values of the male and female adult population. Over this period the mean BMI value for UK males has increased on average at a rate of 0.4% annually and a corresponding average female growth of 0.5%.
Figure 4.5: Historic average BMI value of UK adult males and females
Ultimately BMI data suggests that whilst the average body weight of US citizens is likely to be larger than those of the UK, the trend in the increase of this average has been of a similar magnitude between both nations. Subsequently it may be suggested that if this trend continues then the UK aviation industry is likely to increasingly be subject to issues arising from larger passengers, as has clearly been witnessed in the North American region. It should, however, be recognised that in comparing and analysing proportional-based statistics, the frequency of such occurrences is still likely to remain less in the UK than in the US given that the latter’s total population is five-times greater.
Anthropometric surveys provide a set of definitive body measurements representative of a population being measured at the time the survey is conducted. UK adult weight data from publicly available anthropometric data sources have been compiled in Table 4.2 below, detailing the year from which the values were measured.
Table 4.2 UK adult body weight data compiled from anthropometric surveys
The above data provides an important quantification of the weight gain that has occurred amongst the UK adult population over the past 20 years. It can be seen that between 1988 and 1998 the weight of UK males increased by 4.8kg, a growth of 6.3%, whilst UK females gained an average of 3.7kg, a growth of 5.8%. If this data is considered in conjunction with the mean BMI statistics, it can be assumed that the average weight of UK adults will have increased further following 1998. These known weight increases (1988-1998) will be used later for economic impact assessment of UK weight changes.
The importance of accurate standard weight provisions in regulations is unquestionable in ensuring that all flights, particularly smaller aircraft, are operated in a safe manner. Concurrent with this is the need for overestimating the weight of passengers in order to introduce a level of redundancy against exceeding the operational capabilities of aircraft. The above analysis and calculations suggest that, in the UK at least, this redundancy is now being neglected and given that it is clear that significant weight increases have occurred subsequent to the implementation of JAR OPS-1, arguably the safety of passengers is now being seriously compromised. Similar neglect was clearly made in the US prior to the occurrence of a major aircraft accident, so it should therefore be reiterated that the weight provisions offered under Europe’s JAR OPS-1 regulation are in urgent need of revising in order to guarantee against a similar accident occurring within Europe.
Designated passenger weight analysis
Airlines operating under both European and US regulations are responsible for monitoring and accurately determining the weight of their aircraft. Whether through the use of prescribed values set out in regulatory literature or through self determination of the weight of passengers and baggage, the trend of weight increases in recent decades is likely to have required airlines to allocate increasing amounts of weight to each of their passengers. Here I will seek to analyse historic reported airline statistics to assess to what extent the designated weight of passengers and their baggage has changed over time and its variation between different regions of the world.
“To convert aircraft passenger loads into weight loads, the number of passengers carried is multiplied by a factor representing the average weight of the passenger plus both normal baggage allowance and excess baggage.” This definition is set out in ICAO’s glossary of terms used in civil aviation statistics. It identifies that in the operating statistics of airlines it is possible to calculate the average weight assigned to each passenger and thus allowing the analysis of this designated value both between airlines and its change over time. In order to carry out such analysis the following equation has been used:
Average Passenger Weight and Baggage (kg) = Passenger Tonne Kilometres * 1,000 Passenger Kilometres
Passenger-specific statistics are published annually within the IATA WATS, thus allowing the calculation and analysis of average passenger weights and their baggage. Analysis has been carried out for each individual year, with passenger and baggage designated weights calculated for all scheduled services of the world’s largest 50 international and largest 50 domestic airlines in terms of the total number of passengers carried. It is important to note that up until 2004 the WATS only included those airlines that were IATA members. The data published and used for 2004 and 2005 in this analysis has included non-member airlines as available.
Figure 5.1 has been compiled from the mean weight designated to passengers and their bags by the largest 50 airlines of both international and domestic services. The chart illustrates that international passengers are consistently designated at a higher weight than domestic travellers. The principal reason behind this is likely to be that in general passengers on international services will carry, and are likely to be permitted, more baggage compared to domestic travellers.
Figure 5.1: Mean individual passenger and baggage weight of international and domestic airlines
The data suggests that the mean passenger and baggage weight allocated by airlines is somewhat fluctuant, although it should be noted that the data represents the mean of the top 50 airlines for each year and as such the airlines that feature in each year’s statistics changes on an annual basis. Despite this fluctuation, the trend lines for both data sets identify an overall upward trend over this period with annual increases in international and domestic weights of 0.09% and 0.25%, respectively. This represents an overall increase in mean designated weight of 1.5kg for international scheduled operations and 3.9kg for domestic scheduled operations over this period.
Figure 5.2, below, illustrates the range of values of passenger weights corresponding to the top 50 international operators from each year’s set of statistics. The chart plots the average values, along with the highest and lowest corresponding values for each year. It demonstrates that during each year considered, there exists a considerable variation in the standard weight allocated to each passenger and their baggage, with a mean annual range in allocated weights over this period of 26.3kg.
Figure 5.2: Individual passenger and baggage weight range of Top 50 international airlines
The variability in passenger and baggage weights may be explained by two factors. It is possible that differences between each airline’s baggage allowances and policies may affect the variation in the values illustrated. However, it is unlikely that such differences alone could wholly account for such significant ranges in values and should therefore only be considered a contributory factor. The very presence of a significant range of values in any one year alone re-emphasises the global variability of the underlying principle that airline passengers are getting larger. Undoubtedly some regions will have been subject to much higher and faster growth rates of their population’s average weight, whilst other regions may not have been subject to any growth at all and as such the subsequent difference of weight-related variables between nations will subsequently grow.
Similar trends can also be seen within the variation of the corresponding domestic operator statistics. Figure 5.3 below provides a chart again plotting the mean and range of values for domestic services in each year studied.
Figure 5.3: Individual passenger and baggage weight range of Top 50 domestic airlines
The domestic data shows a mean range over the period studied of 30.0kg and an average annual growth in the size of this range of 6.8%. Subsequently the domestic-based data is corroborative with the international-based data in showing that the variation found in passenger and baggage designated weights has historically been present and to some extent increasing.
The data assessed thus far has incorporated statistics from airlines operating within and between numerous countries across all continents. With much of the focus of this research placed upon the issue of passenger size in the western world, regional-based analysis for Europe and North America has been produced. This has been achieved by extracting the reported statistics of the European and North American based carriers that featured in each year’s top 50 statistics. Whilst it is important to highlight that by doing so a much smaller sample of airlines are being considered, the identification of any important trends and differences is made possible.
Figures 5.4 and 5.5, below, show the extracted data corresponding to the European and North American carriers that featured in the top 50 airlines in terms of passengers carried on international services.
Figure 5.4: Allocated passenger and baggage weight range of European International Airlines
Figure 5.5: Allocated passenger and baggage weight range of North American International Airlines
Designated passenger weight analysis
Comparison of the two data sets shows that the average weight allocated to each individual passenger and their baggage is consistently higher amongst European carriers than their North American counterparts. This is somewhat surprising given that the mean weight of North Americans is higher than that of Europeans. Furthermore, over this period the European weights have increased on average by 0.1% annually, whilst North American weights have not exhibited any significant annual growth at all.
Furthermore the data shows that variation in passenger and baggage weight between airlines in any one year is much higher in Europe than in North America. This is emphasised by an average standard deviation of passenger weights over the 19-year period considered of 4.66kg for Europe compared to a corresponding value of 1.43kg in North America. This may be explained by the size and nature of the two regions combined with what actually constitutes an international flight. For the purpose of this analysis North American statistics have been compiled from carriers registered in the US and Canada, whilst European statistics combine a much larger number of countries.
In the UK, for example, international services vary greatly in sector length from short-haul services to Ireland, France and Germany, to long-haul flights across the globe. The geographical extent and situation of North American countries implies that, in general, international flights are likely to be much longer on average, with fewer extremities in the range of international sector lengths compared to European countries. Furthermore there may indeed be a much greater variation in actual passenger characteristics in Europe compared to the US and Canada. It should also be noted that the statistics presented are representative of a greater number of European carriers than North American carriers. This difference in sample size may also impact upon the differences seen between the two regions.
In order to assess to what extent these values adhere to the standard weight recommendations of their respective regulations, the standard passenger weights and standard baggage weights offered by the regulatory authorities have been combined. Regulations currently designate a standard weight per passenger, including baggage, of 100kg in the US and Canada and 98kg in Europe. Over the 19-year period being assessed, and in particular the most recent of reporting periods, it can be seen that the majority of airlines in both Europe and North America have assigned a standard passenger and baggage weight significantly less than the current recommended prescribed values set by their respective regulative authority.