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1 PROFILE OF COMMERCIAL AIR TRAVEL This chapter provides background information on aspects of commercial air travel pertinent to the study of airliner cabin air quality. The study of cabin air quality must take into account both routine flights and emergency situations. Therefore, this chapter presents statistics regarding routine travel--including data on passengers, flight and cabin crews, and aircraft--and enumerates the mayor types of emergencies that affect air quality, including smoke, fumes, fire, explosion, and depressurizatlon. PASSENGERS For most Americans, exposure to an airliner cabin environment is infrequent and brief, although 70% of American adults have flown at least once. According to a Gallup survey conducted in the summer of 1985, 28X of American adults had flown in the preceding 12 months; 14% had taken only one trip, and 1X, 10 or more.6 Of those who flew in the 12 months before the survey, 50YO had taken only one trip and 5X, 10 or more (see Table 1-1~. Passenger demographic data appear in Table 1-2. In 1984, 343,264,000 passenger enplanements occurred on U.S. scheduled airlines, for a total of 304,458,727,000 revenue passenger miles.2 Figure 1-1 illustrates passenger enplanements projected through 1996; Figure 1-2 shows historical and projected passenger load factors. Table 1-3 lists numbers of passengers carried and total revenue miles by selected airliner in 1984. 24

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25 TABLE 1-1 Frequency of Flying Among the General Public, 1985a No. Trips in % of Adult Preceding 12 Months Population % of Airline Passengers 1 14 49.8 2 7 22.8 3 2 8.0 4-6 3 11.4 7-9 1 3.1 10+ 1 4.9 Total 28 100.0 . a Data from Gallup.6 TABLE 1-2 Demographic Characteristics of Airline Passengers, 1984a Proportion of Descriptor Passengers, X Age group: <18 11 27 18-24 10 13 25-34 21 17 35-44 23 13 45_54 16 9 55-64 10 9 65+ 9 12 Sex: Male 54 49 Female 46 51 Proportion of UeSe Population, Xb a Data from U.S. Travel Data Center:5 and U.S. Bureau of the Census.~ b Based on 1983 estimates.

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26 600 500 400 300 200 100 o _ International _ 1~///~ Domestic _ ~E? 1984 1986 1988 1990 FISCAL YEAR 1992 1994 1 996 FIGURE 1-1 Scheduled passenger enplanements on U.S. certificated air carriers. Reprinted from U.S. Federal Aviation Administration. 74 Historical 70 66 58 54 50 .. . V..~-..- . 1 ~ , .. Forecast International _ . - ~ ~ ~ - - ~ ~ ~ Domestic , 1980 1982 1984 1986 1988 1990 1992 1994 1996 FISCAL YEAR FIGURE 1-2 Passenger load factor on U.S. certificated air carriers. Reprinted from U.S. Federal Aviation Administration.

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27 TABLE 1-3 Airline Passengers and Passenger Miles Flown, 1984a Passengers, thousands Revenue Passenger Miles, thousands United 41,01046,037,064 Eastern 38,08129,359,288 Delta 37,34127,040,102 American 34,12336,702,296 Trans World 18,48728,296,956 US Air 17,0478,190,589 Republic IS, 1778,509,948 Piedmont 14,2746,227,641 Pan American 13,91328,066,826 Northwest 13,21619,772,356 Southwest 12,0524,669,435 People Express 11,7757,770,945 Continental 11,11510,923,395 Western 10,6389,396,580 Pacific Southwest 7,8303,047,338 Frontier 7,0484,464,168 Ozark 4,9492,693,866 Air Cal 3,9901,548,506 Hawaiian 3,022403,857 New York Air 2,793937,102 Alaska 2,5431,841,212 American West 2,3981,247,134 Aloha 2,346392,421 Braniff 2,1761,885,619 Muse 1,980925,083 Northeastern 1,6551,652,119 Midway 1,464747,428 World 1,4103,889,001 a Data from Air Transport Association of America.2

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28 FLIGHT ATTENDANTS FLIGHT CREW The populations mostiexposed to the aircraft environment are flight attendants and flight crew members. These two groups, however, are exposed to different conditions. Flight attendants spend almost all their time in the passenger cabin and galleys, and the flight crew spend almost all their time in the cockpit. The cockpit and passenger cabin are ventilated separately, and the former has a much higher air- exchange rate and hence generally cleaner air. The Federal Aviation Administration (FAA) restricts most pilots to a maximum of loo h of flight time per month, 5 and labor contracts impose an even lower limit. The flight time of cabin crew is not regulated, although the Association of Flight Attendants (AFA) has petitioned FAA for rule-making to establish maximal duty hours and minimal hours of rest.3 In 1984, 80X of flight attendants flew 70-85 h/mo.9 The average age of airline pilots is 41.5 yr, and their average length of employment with their current airline is 12-13 yr, according to data from the FAA Civil Aeromedical Institutel 3 and the Air Line Pilots Association (personal communication, 1985~. Flight attendants have a median age of 34 yr (see Table 1-4), with 22% under 30; their average length of employment with their current airline is around 15 yr. Although 99% of pilots are men, 85% of flight attendants are women; 61% of flight attendants are married, and 43X have children.8 9 13 THE U.S. AIRLINE-INDUSTRY When gathering or reporting information on the nation's air carriers, FAA distinguishes between certificated route air carriers, which operate under the ruler of Title 14, Part 121, of the Code of Federal Regulations (14 CFR 121~4 and hold certificates of public convenience and necessity, and commuters or air taxis, which operate under 14 CFR 135.1

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29 TABLE ~ 4 Demographic Characteristics of Flight Attendants, 19858 D.~griDtor Age, vr: <26 26-29 30-34 35-39 40-44 45-49 50+ Ro. years employed with current airline: <1 1-5 5-10 10-15 15-20 >20 Race: Black Asian Hispanic White Other Proportion of AFA Members, % 15 29 30 13 4 2 10 13 22 22 23 10 86 3 Highest education achieved: High-school graduate 16 Some college 22 2 yr of college 24 4 yr of college 32 Some graduate school 4 Postgraduate degree 2 Average monthly hours flown, 1984 <70 70-74 75-79 80-85 >8S L 12 18 28 34 8 a Data from Peter D. Hart Research Associates.9

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30 In 1984, there were 67 certificated air carriers; 47 were engaged in scheduled air carrier services, and the remainder provided nonscheduled (mainly charter) services. FAA classifies Part 121 airlines according to their annual operating revenues. A mayor airline has annual operating revenues of over $1 billion; a national airline, $75 million-$1 billion; a large regional airline, $10-$75 million; and a medium regional airline, less than $10 million. In 1984, the 11 mayor U.S. airlines accounted for 67.4% of scheduled domestic enplanements and 79% of scheduled domestic revenue passenger miles (compared with 96% in 1978, before deregulation). National carriers accounted for 23.3X of scheduled domestic enplanements in 1984. The large and medium regional airlines carried 3.8% of the travelers.11 12 Figure 1-3 characterizes the U.S. commercial aircraft fleet by mayor aircraft type. Table 1-5 lists the major aircraft used by U.S. certificated air carriers projected through 1987. Wide-body aircraft (B-747, B-767, A-300, DC-10 and L-1011) accounted for 43% of the total capacity in 1984 (Table 1-6~. Four aircraft models (B-727, DC-9, B-737, and DC-8) accounted for an additional 53%. The remaining seating capacity was primarily on medium or large models being phased into or out of the market and on small aircraft. Flight time and total seating capacity for U.S. airlines in 1984 are presented by aircraft type in Table 1-6. In 1984, the approximately 175 commuter airlines carried 5.5% of the passengers and accounted for 1.1X of the total revenue passenger miles. 12 Of the aircraft used by commuter airliner in 1984, 77.5X had fewer than 20 seats. Because small aircraft account for a very small percentage of the total revenue passenger miles flown and ventilation rater on small aircraft are generally much higher than on larger planes, this study does not address in any detail the problems associated with air quality in there aircraft.

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31 4000 3000 A: cat - 2000 C : 1000 n 2 Engine Wide-Body 35% >I l ~ - 2 Eng WB 3 Eng We _ | 4 Eng WB 2 Eng NB 3 Eng NB Eng NB 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 CALENDAR YEARS 4 Engine Wide-Body 5.3% I_ 1984 )~ 3 Engine Wide-Body 9.9% 1 2 Engine Wide-Body 3% \p 4 Engine Narrow-Body ~/ 5.9% 3 Engine Narrow-Body 40.9% ~ . 1995 1996 / 2 Engine Narrow-Body 53.5% 4 Engine Wide-Body 6.6% engine Wide-Body 7.4% / / \, 2 Engine wide-Body 1 / / A\ 12.8% 4 Engine Narrow Body 3% ,_~/3 Engine Narrow-Body 16.7% 1 996 FIGURE 1-3 Large jet aircraft in U.S. commercial airline service. Reprinted from U.S. Federal Aviation Administration.

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33 TABLE 1-6 Flight Time and Exposure of Public on U.S. Airliners, 1984a Est. Ave. Seat-hours, No. in Seating Total Plight thousands Manufacturer Modelb Fleet CeDacitv Time, h (% of total) Boeing 8-7271-,161 1202,990,821 358,899 (27.72) Boeing B-747156 452537,142 242,788 (18.75) McDonnell Douglas DC-9594 1151,438,339 165,409 (12.77) McDonnell Douglas DC-10174 310487,831 151,228 (11.68) Boeing B-737391 1201,006,238 120,749 (9.32) Lockheed L-1011103 300308,180 92,454 (7.14) Boeing B-76753 250172,705 43,176 (3.33) McDonnell Douglas DC-8157 150270,728 40,609 (3.14) Airbus A-30038 280101,143 28,320 (2.19) Boeing B-75719 20050,022 10,004 (0.77) British Aerospace BAC-11133 10059,555 5,955 (0.46) British Aerospace BAE-14614 10014,140 1,414 (0.11) Boeing B-70722 14539,243 5,690 (0.44) de Havilland DHC-746 50106,287. 5,314 (0.41) de Havilland DHC-6107 20176,233 3,525 (0.27) Beechcraft BE-9985 15199,205 2,988 (0.23) turbo Fokker F-2823 7033,036 2,313 (0.18) Fairchild F-2723 4435,521 1,563 (0.12) Fokker F-2714 5625,056 1,403 (0.11) Piper PA-31110 10114,330 1,143 (0.09) Cessna C-402112 6166,914 1,001 (0.08) ... Fairchild F-2279 4817,053 819 (0.06) a Data from U.S. Federal Aviation Administration.l2 b Includes models with seat-hours greater than O.O1X of total. FAA DATA ON SELECTED INCIDENTS Commercial air carriers are required to report each accident or incident that involves a threat to the airworthiness of an aircraft or to the safety of passengers. The reports are recorded in the FAA Accident/Incident Data System. Table 1-7 summarizes the sources of in-flight fires and explosions, ground fires, and occurrences of cabin smoke from 1980 to 1985, and Table 1-8 summarizes emergency descents and deployments of oxygen masks in the same period (see Appendix B for complete listings from the FAA Accident/Incident Data System). Table 1-9 summarizes incidents that involved smoke or fumes in cockpits and cabins in 1974-1983, according to a separate data base, the FAA Civil Aeromedical Institute's Cabin Safety Data Bank. Emergency situations are discussed in greater detail in Chapter 4.

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34 TABLE 1-7 - In-Flight Fires and Explosions, Ground Fires, and Cabin Smoke, 1980-1985a No. In-Fllght No. Reported Fires or Explosions Incidents of Source of Accident or Incident and On-Ground [ires Cabin Smoke Mechanical failure (including 38 30 engines, landing gear, air conditioning, etc.) Electric malfunction 5 20 (including navigation, communication, and control instruments, etc.) Food-service galley 2 5 (except ovens and food) Ovens or food 3 5 Passenger cabin: cigarettes 4 1 and lighters Passenger cabin: other 1 2 (including lighting, pro] actors, speakers, etc.) Lavatories: paper And waste chutes 4 1 Lavatories: other 5 O Cargo compartment 1 - Deicing malfunctions (e.g., deicing fluid) Other 3 4 Undetermined - 4 Total 63 75 a Data from FAA Accident/Incident Data System (AIDS). See Appendix B.

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35 TABLE 1-8 Emergency Descents and Deployment of Oxygen Masks, 1980-1985a Cause of Incid Engine malfunction (e.g., bleed-air ports, turbine failure, power loss, fire warning system, and fire) Ventilation system failure (e.g., air-conditioning turbine, ducting, outflow valve, and water separator) Control equipment malfunction (e.g., electric panel, fire prevention system, pressure controller, and broken wire) Landing gear malfunction (e.g., hydraulic fluid loss) . . Medical (e.g., passenger illness or flight crew member unconscious) No. Incidents 8 14 23 1 2 Other (e.g., hydraulic flap failure, 6 burst water tank, wiring pylon cracked, bird in valve, fuselage skin fatigue, and bomb threat) Unknown or unclassified Total a Data from the FAA Accldent/Incident Data System (AIDS).14 See Appendix B. 17 71

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36 TABLE 1-9 Incidents Involving Smoke or Fumes in Cabin or Cockpit, 1974-1983a No. Incidents No. Incidents No. Incidents with Emergency with No Emergency with Unlmowst Total No. YearLanding Declared Landing Status Incidents 19749 2 7 18 197511 1 4 16 197614 1 7 22 197711 8 2 21 197813 2 2 17 197919 3 2 24 198017 4 0 21 19819 7 1 17 198210 5 5 20 198317 9 4 30 Total130 42 34 206 a Data from Higgins.7 REFERENCES 1. Air taxi operators and commercial operators. Code of Federal Regulations, Title 14, Pt. 135. Washington, D.C.: U.S. Government Printing Office, 1985. 2. Air Transport Association of America. Air Transport 1985: The Annual Report of the U.S. Scheduled Airline Industry. Washington, D.C.: Air Transport Association of America, 1985. 3. Association of Flight Attendants. Petition of Proposed Rule Making. 1985. (unpublished) 4. Certification and operations: Domestic, flag and Supplemental air carriers and commercial operators of large aircraft. Code of Federal Regulations, Title 14, Pt. 121. Washington, D.C.: U.S. Government Printing Office, 1985. 5. Flight time limitations: All flight crewmembers. Code of Federal Regulations, Title 14, Pt. 121.471. Washington, D.C.: U.S. Government Printing Office, 1985.

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37 6. Gallup Organization, Inc. 1985 Air Travel Survey. Washington, D.C.: Air Transport Association of America, 1985. 7. Higgins, E. A. Protective breathing: Oxygen mask use/problems, pp. 61-65. In Flight Safety Foundation, Inc. Proceedings of Cabin Safety Conference and Workshop, December 11-14, 1984. Washington, D.C.: U.S. Federal Aviation Administration, Office of Aviation Safety, 1985. 8. Joint Council of Flight Attendants Unions. About the Joint Council. (unpublished communication, 1985) 9. Peter D. Hart Research Associates, Inc. Membership Survey, Association of Flight Attendants. 1985. (unpublished) 10. U.S. Bureau of the Census. Statistical Abstract of the United States, 1985. 105th ed. Washington, D.C.: U.S. Government Printing Office, 1984. 11. U.S. Federal Aviation Administration. FAA Aviation Forecasts, Fiscal Years 1985-1996. FAA-APO-85-2. Washington, D.C.: U.S. Federal Aviation Administration, 1985. 12. U.S. Federal Aviation Administration. FAA Statistical Handbook of Aviation, Calendar Year 1984. Washington, D.C.: U.S. Federal Aviation Administration, 1985. 13. U.S. Federal Aviation Administration, Civil Aeromedical Institute, Aeromedical Certification Branch. 1984 Aeromedical Certification Statistical Handbook. AC 8500-1. Washington, D.C.: U.S. Federal Aviation Administration, 1985. 14. U.S. Federal Aviation Administration, Safety Analysis Division. Analyses Performed 3 Dec. 1985 and 6 Jan. 1986 Using Accident/Incident Data System (AIDS) for Committee on Airliner Cabin Air Quality. (computer printouts)

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38 15. D.S. Travel Data Center. Hation.1 Travel Survey: 1984 Full Year Report. Washington, D.C.: U.S. Travel Data Center, 1985.