The sheer number of hours spent moving about an aircraft cabin leaves flight attendants more vulnerable than passengers to the risk of injury from a severe turbulence encounter. Several presenters explored this safety disparity during the International Aircraft Cabin Safety Symposium (CSS) conducted by the Southern California Safety Institute in February 2009 in Torrance, California, U.S.
In February 2008, serious injuries to two flight attendants aboard a Boeing 737-600 prompted Scandinavian Airlines (SAS) Norway to institute several changes, said Anne Lea Wittrup-Thomsen, an air purser, cabin safety coordinator and cabin investigator assigned to assist the Accident Investigation Board Norway for this accident.
“About 10 minutes to landing at Trondheim, Norway, the ‘FASTEN SEAT BELT’ sign had been switched on at 12,000 ft and the aircraft was crossing over a lake at approximately 7,000 ft,” Wittrup-Thomsen said. “The two aft cabin crewmembers were making final preparations before landing and were about to sit down. One had reported ‘cabin clear’ [to the flight deck] when they could feel several hard shaking [forces] from the tail of the aircraft, later described as a sideways shaking … quite unusual, not like normal turbulence. One described the feeling as being up in space, like she was weightless, and said she kept thinking that she needed to grab the handle next to the aft passenger door. Before she managed to do that, the tail shook violently and both cabin crewmembers were lifted from the floor and hit their heads against the ceiling. Both came around on the floor after a little while.”
One then told the other that she had pain in her tailbone and back; she crawled along the aisle and called for help from passengers. The other flight attendant whispered to her colleague that she was having difficulty breathing. A nurse and a physician on the flight immediately assisted them, including administering oxygen.
The purser, occupying the forward lavatory, experienced a “normal level” of turbulence and remained unaware of her coworkers’ injuries until she left the lavatory. The flight crew then made an announcement for the cabin crew to be seated but, after being told about the situation by the purser, asked air traffic control to arrange for emergency medical services to meet the flight.
After landing, the injured flight attendants were lowered to ground level with assistance from a catering truck operator and then transferred to an ambulance. The flight attendant who had difficulty breathing, initially considered the most serious case, was treated for broken ribs at a hospital and released the same day to a hotel. She returned to her home base city the following day but remained off duty for about six weeks.
“The other cabin crewmember had swelling and fluid in her spine which made [her condition] difficult to diagnose,” Wittrup-Thomsen said. “The compression damage was due to a [tray] table that pressed against her vertebrae; however, she returned to base in the afternoon of the same day. A full body X-ray detected a week later that she had a broken vertebra. She was off on sick leave for two months.”
Among findings from the airline’s investigation were that the flight crew had not understood from the purser’s post-flight debriefing the severity of either the turbulence encounter or the aft cabin crewmembers’ injuries. After exiting the aircraft, the pilots operated their next scheduled flight to Oslo. ”Both the commander and the first officer later stressed that the turbulence had lasted for a split second, so they could not imagine that anything [serious] could have happened,” Wittrup-Thomsen said.
Analysis by SAS of its flight data monitoring program database showed that descents through altitudes between 7,000 ft and 12,000 ft historically had the greatest risk of unexpected turbulence encounters. The airline’s cabin safety reports contained 25 events related to turbulence from 2002 to 2008. Based on this information and other industry recommendations, policy and procedures were revised in mid-2008 to require that cabin crews complete all cabin duties, occupy their jump seats and fasten their harnesses by the time the flight crew signaled descent below 15,000 ft.
Recognition of time pressure affecting cabin crews during flights of less than one hour also led to a change in the dress code. SAS Norway quit requiring that female crewmembers change onboard from boots to shoes while wearing uniform skirts or dresses for cabin service, then back to boots for landing. All turbulence-related policy/procedure changes were communicated quickly through e-mail messages, the crew magazine, the company newspaper, leaflets and preflight briefings by commanders.
“Flight deck crews reported [at a November 2008 follow-up meeting] that on several occasions, in spite of the ‘FASTEN SEAT BELT’ sign being switched on at 15,000 ft, cabin crew were still operating in the galley making final preparations as low as 8,000 to 9,000 ft,” Wittrup-Thomsen said.
“So pilots were a bit concerned about awareness and respect for the sign. … We found that … cabin crews have many things to do, but if they have prepared and planned the flight for the time available, it should be sufficient to respect the sign. … Turbulence is more serious in the aft than in the front, and we opened up a dialogue so cabin crew working in the aft can call the flight deck and tell the pilots to switch on the ‘FASTEN SEAT BELT’ signs when they experience turbulence. If flight attendants know what kind of weather conditions they are flying into, they also can make use of the threat and error management system … to always be a step ahead. We also discussed the correct seating position because we have had a lot of injuries where they have been sitting incorrectly on their jump seats.”
Considering many solutions, the company rejected the idea of disciplinary action for nonadherence to the new procedure as inconsistent with non punitive safety reporting, she said, adding that further changes still may be necessary. In February 2009, a turbulence encounter at 8,000 ft on descent to Tromsø — lasting two or three seconds and currently under investigation — caused one flight attendant to suffer a broken leg.
“Are we our own worst enemy?” Wittrup-Thomsen asked attendees. “If cabin crews don’t respect the ‘FASTEN SEAT BELT’ sign, if we don’t have situational awareness on our minds every day, we are bound to have accidents. … In both of our accidents, the signs were on, and cabin crews possibly chose to put service ahead of safety. I don’t know; I will have to look into the latest accident.”
Mandatory Seat Belts
Lufthansa also has tackled this risk of injury. The airline now requires — not recommends — that passengers keep their seat belts fastened whenever they occupy their seats. This policy was implemented in 2008, said Matthias Honerkamp, a captain, check pilot on Airbus A330 and A340 fleets, and manager of training standards and crew safety training, and Grit Matthiess, a purser for the airline.
Lufthansa flight crews and cabin crews previously had fallen into practices much like those recently recognized within SAS Norway. “FASTEN SEAT BELT” signs formerly had been illuminated by the flight crew — often without a public address announcement — to signal passengers to be seated even during light chop.
Each time, however, the cabin crew had to walk the aisles, sometimes interrupting meal service or leaving the security of their jump seats, to check that passengers had fastened their seat belts. This was nearly impossible at night when passengers had to be awakened if they were asleep or if their seat belts were concealed by blankets. Meal service formerly was continued regardless of illuminated seat belt signs. The signs so often were illuminated for long periods without an explanation that they lost their warning effectiveness.
“Our key case in August 2003 was an A340 accident during a climb to Flight Level 240 [about 24,000 ft] on the way to Houston,” Honerkamp said. “The flight experienced very strong turbulence because the A340 hit the top of a fast-growing embedded/obscured cumulonimbus cloud not seen on the weather radar until within 60 to 100 nm [111 to 185 km] while the crew was dodging other thunderstorm clouds. The aircraft was lifted up with 2.3 g [2.3 times acceleration by gravity] and then was pushed down with minus 0.9 g within two seconds. We had two passengers with serious injuries and  passengers and three cabin crewmembers with minor injuries. One finding was that the seat belt signs had been switched on before the encounter, but despite that, many people had their seat belts unfastened.”
When the severe turbulence was encountered, the cabin crew were involved in the breakfast service, Matthiess said. “They had no chance to reach their flight attendant jump seats or to fasten their [harnesses],” she said. “The signs were on, and nobody actually noticed them. The cabin crew continued their service.”
Data from 1981 through 1997 show that worldwide, 91 percent of seriously injured passengers did not have their seat belts fastened during the turbulence encounter. “For us, that led to one logical solution … no question about where we had to go,” Honerkamp recalled. “Passengers would have to be obligated to wear their seat belts at all times.”
In proposing to exceed current European regulations on seat belt use, Lufthansa advised the Federal Office for Civil Aviation of Germany (Luftfahrt-Bundesamt or LBA) of the plan, and the LBA consented to the discontinuation of en route seat belt checks by cabin crew after “FASTEN SEAT BELT” signs were illuminated so long as the flight crew followed each illumination with a PA announcement so that “the passenger is clearly informed.”
Lufthansa’s new policy requires a public address announcement with each illumination and guides flight crews on when to illuminate the signs. “If we expect moderate turbulence or we encounter moderate turbulence, we are required now to switch on the ‘FASTEN SEAT BELT’ signs,” Honerkamp said. At this level of severity, cabin occupants feel strain against their seat belts, unsecured objects are dislodged, and service and walking are difficult. The legal authority behind the policy comes from a brief change to contractual terms and conditions of carriage accessible via a link on the home page of the Lufthansa Web site.
Under Article 11, “Conduct Aboard Aircraft,” paragraph 11.4, “Seat Belts Compulsory,” the terms and conditions say, “While being on your seat on board the aircraft, you have the obligation to fasten your seat belt during the entire flight.” Separate from the preflight briefing, the purser also makes an announcement saying, “Air turbulence can occur at any time unexpectedly. You are required to fasten your seat belts as soon as you have taken your seat. This is in the interest of your own safety.”
When the seat belt sign is on, all passengers must return to their seats and fasten their seat belts. Otherwise, passengers are free to walk around, go to the lavatory or visit with other passengers or flight attendants in galley areas.
“Now, when an announcement is made by the cockpit crew, everybody is aware that turbulence is a threat,” Honerkamp said. “The service is reduced whenever the signs have been switched on, but it may be continued with the captain’s approval after the cabin crew has been advised by the captain about what kind of turbulence the flight crew is expecting.”
Cabin Crew LOSA
Auditing allows trained observers to see how time constraints in line operations affect readiness for turbulence encounters and performance of other safety duties, said Nina Haubold, manager cabin audit, Flying Operations Audit, Qantas. “For unanticipated turbulence during flight, cabin auditors really look at what is out there in our cabins during service time that potentially can harm the cabin crew and our passengers,” Haubold said.
A line operations safety audit (LOSA) program for the cabin has made 360 observations since 2005, with each aircraft fleet audited at intervals of 18 to 24 months, she said. The 20 Qantas cabin safety auditors — each observing four sectors per year — are fully qualified, current and operational cabin crew who have received formal training in systemic threat and error management (TEM) principles and how to code qualitative human factors as threats, errors and undesired aircraft states.
They work in uniform but do not perform non-emergency duties of the operating crew. “They observe regular scheduled flights and collect safety-related data on the environmental conditions, operational complexity and cabin crew performance,” she said. “The observations and resulting narratives … describe how the crews managed threats and errors, and provide an operational context for the data, which are independently reviewed and validated.”
As part of the airline’s safety management system, the cabin audit program enhances safety and reduces cost by eliminating conventional line checks of more than 6,500 cabin crewmembers under impending regulatory requirements. Six months typically elapse from observation to final report, and standards call for action items to be resolved within three months.
“What we are asking crews to do is not modify their behavior, so that we can see how they operate in their natural environment,” Haubold said. “A guarantee of anonymity is given in order to enhance to prospect of being able to observe the true day-to-day operation of that fleet.” In the interest of objectivity, auditors cannot provide direct feedback to the operating cabin crew. If they observe a situation that seriously affects safety of flight, they contact the captain or base chief pilot as appropriate.
After the cruise phase of flight, the highest rate of threats has been observed during the period from the preflight briefing until the final door has been closed for departure. “It is a very time-compressed period, cabin crew are doing their emergency equipment checks … and they’ve got the ground staff on their backs trying to get the aircraft out on time,” Haubold said. “From all our observations to date, 91 to 95 percent of all errors are procedural errors — that is, where a crew member undertakes an action outside of the … documented procedures. The high-ranking errors are failures to complete [all components of] the emergency equipment–effective checks preflight.” Such errors will be categorized as “intentional noncompliance” only if the observer hears the cabin crewmember verbalize a deliberate plan to do something that falls outside of standard operating procedures.
An example of a recurrent problem found in audits has been cabin crew insistence on conducting their own detailed pre-departure checks of catering cart contents instead of relying on the preparations by ground staff. This practice, however, has been a persistent concern because it intrudes into time allotted for preflight safety checks.
Benefits of cabin crew LOSA audits have included higher awareness of safety responsibilities among flight attendants; enhanced policies and procedures; new recurrent training on normal operating procedures; updated, reorganized and tightly controlled content revisions in cabin crew manuals; new cabin standard orders that supersede manuals between revisions; upper management tracking of agreed actions to fix issues noted in audit findings; improved communication; and more disciplined cabin safety operations committee meetings.
Advanced Qualification Program
U.S. airlines can gain expanded flexibility to design their training under the voluntary Advanced Qualification Program (AQP) of the Federal Aviation Administration (FAA) compared with following the regulations for standard flight attendant training, said Chris Hallman, founding principal of Great Circle Consulting. AQP emphasizes requirements for “scenario-based training that will force flight attendants to demonstrate proficiency in both their technical or procedural capability and their crew resource management skills,” he said.
Among major differences are the AQP requirements to collect and analyze data about scenario-based flight attendant performance and proficiency, and elimination of inflexible programmed hours of training for greater efficiency under AQP. Some of the best uses of the data are to refine and customize existing curricula, and to document the effectiveness of high-tech cabin trainers and e-learning, he said.
“Maybe the airline has had a rash of incidents in line operations, for example,” Hallman said. “AQP gives the flexibility to immediately go in and adjust that training curriculum, generally in the recurrent [training] environment. It is not static training at all, it is very dynamic — constantly looking at what is going on in the real world and trying to turn that into relevant training material for the training center. AQP programs also require a specific, rigorous instructional design foundation and focus on training instructors and evaluators … and building the idea of systems thinking,” Hallman said.
Instructors themselves can be calibrated — that is, trained to perform at the same level of reliability and consistency — which is very difficult to achieve outside the AQP strategies, he said. Nevertheless, the program is not for all airlines because of the two-year start-up and ongoing commitment of full-time technical staff, especially to handle data management, analysis and reporting to the FAA and management; rewriting of operational training manuals; and the difficulty of returning to conventional training.
Consequences for Unruly Passengers
Other presentations of the 2009 CSS also showcased innovations. For example, airlines of Japan since 2004 have collaborated frequently with police to manage unruly/disruptive behavior aboard commercial aircraft through safety-focused laws, clear warnings and procedures, rapid enforcement and stiff penalties, said Akemi Inukai, manager, corporate safety, for All Nippon Airways (ANA). “With this amendment to the law, we can take a more firm attitude toward any unruly behavior and will not hesitate to report it to the police or to another appropriate law enforcement authority if necessary,” Inukai said. “The captain has the right to issue a prohibition order to cease [eight acts impeding safety aboard aircraft]. If acts are continued or repeated despite the prohibition order, the passenger is violating the law and may be subject to a fine up to ¥500,000 [about $5,090].”
The new system, in effect, aligns the duties of police officers with those of cabin crewmembers faced with unauthorized operation of doors or other exits; smoking in the lavatory; interference with cabin crew duties; prohibited use of portable electronic devices; ignoring cabin crew instructions to fasten seat belts; refusing to return seat backs, tray tables or footrests to their original position before takeoff or landing; cluttering evacuation routes with unstopped baggage; and unauthorized use of emergency equipment. The airline also can ban the passenger from flying or require a declaration of indemnity for carriage on future flights.
“From 2004 to 2006, the major issues at ANA were smoking in the lavatories, using improper electronic devices and interfering with cabin crew duties,” Inukai said. In March 2007, for example, a passenger who continued to use his five mobile phones — and obscene language — after he was issued a prohibition order was arrested by police and fined ¥500,000.
Diagnosing Bleed Air Illness
Innovative approaches also have improved medical diagnosis of adverse health effects in flight crews and cabin crews from workplace exposure to bleed air contaminants, defined as pyrolized engine oils and hydraulic fluids that leak into the aircraft cabin and flight deck air supply systems (ASW, 4/08, p. 48). Robert Harrison, a physician and clinical professor of occupational and environmental medicine at the University of California San Francisco, told the symposium that “better engineering and maintenance … elimination of the possibility that these [aircraft mechanical] systems could fail” will be a key to resolving this contentious issue.
As a member of the FAA-funded Occupational Health Research Consortium in Aviation and in collaboration with the FAA’s Airliner Cabin Environment Research Center of Excellence, he participated in the August 2008 publication of the free 24-page Exposure to Aircraft Bleed Air Contaminants Among Airline Workers: A Guide for Health Care Providers.
In February 2009, a new two-page reference guide also was posted at <www.ohrca.org> and he encouraged flight attendants to download both documents for self-education and to educate health care professionals. Health care professionals currently lack even an agreed case definition as their starting point, he said, so he has proposed one that requires “a documented exposure to a bleed air contaminant or a history of flying on an aircraft known to have an increased risk of air supply contamination events.”
“In 25 years, I have probably seen three or four dozen airline cabin crewmembers referred to me for difficult, unresolved chronic medical conditions related to exposure to [contaminated] cabin air,” Harrison said. “Typically, my patients will tell me that they saw mist or haze in the air, there was an odor, they had a symptom, and they failed to get better. … My first step is always to ask myself, ‘Was there an exposure?’ … some objective documentation of acute or persistent signs or symptoms somewhere in a nursing record or other health care provider note … that correlates with the health problem.”
Despite ambiguity about whether the cause of a cabin crewmember’s respiratory, neurologic, systemic, psychiatric or dermal symptoms have been caused by bleed air contaminants, patterns have emerged that help physicians assess that likelihood. “The initial symptoms have to happen within 48 hours of exposure,” Harrison said. “This is important because — if someone has a delayed effect and says, ‘I had an exposure three months ago … I was fine, but now I have a problem’ — I don’t think we can consider that work-related. To my knowledge, there is no latency, no delayed effect.”
To proponents of evacuation simulation technology, the A380 evacuation demonstration that Airbus conducted in 2006 represents more than a step toward launching a new airplane type, said Brian Peacock, a professor at Embry-Riddle Aeronautical University–Prescott [Arizona, U.S.] and a specialist in ergonomics engineering (ASW 1/07, p. 46, and ASW 4/08, p. 47). Aside from cost, planning time, human resources and risk of injuries to human evacuees, a key problem for the industry is that an evacuation demonstration only demonstrates one set of conditions, Peacock said.
Simulation only can be as good as its mathematical model, but offers accuracy, validity, efficiency, simplicity, versatility, repeatability, economy and safety, he said. “The trick is to simplify the model and then run it just like a demonstration — but we can run it over and over again with many different conditions,” Peacock said. “There is enormous variability in the behaviors of people. Slow passengers, injured people, obstacles all come together to affect the reality of an evacuation, which is very unlike the A380 demonstration we saw.”
Operators ideally could model and apply to training scenarios factors such as disability, incapacitation, immobility, stumbling, reverse flows, aggression, cooperation, panic, kin behavior — individuals such as family members who try to stay together during an evacuation — and passengers who impede themselves and others by taking their carry-on baggage.
Using queuing theory, the variables can be expressed as relationships among the number of entities, that is, passengers and crewmembers; queue length; queue logic; entity speed from 1 to 6 mph (1.6 to 9.7 kmh); resources such as doors, aisles and flight attendant flow management and redirection; release conditions for when an unavailable resource becomes available; service activity constraints and rates; queue discipline; statistical distributions; branching within queues from jockeying, balking and reneging; and optimal throughput rates.
Ensuring RFID Safety
Since the publication of Advisory Circular 20-162, Airworthiness Approval and Operational Allowance of RFID Systems, in September 2008, the FAA has conducted an educational outreach to help flight attendants and other aviation professionals understand the nature of radio frequency identification (RFID) devices — often called tags — that look like a small foil strip or stamp with a microcircuit and possibly a battery or solar cell.
This part-marking technology will be used increasingly on galley/service carts, line-replaceable units in the electronics and equipment bay, baggage, mail containers and cargo devices. In the cabin, flight attendants may encounter RFID tags on passenger convenience items such as pillows, headsets and blankets or service provisions such as towels or coffee service products.
Tim Shaver, assistant manager of the Avionics System Branch, FAA Aircraft Certification Engineering Division, told the symposium that data — such as a serial number, date of manufacture or temperature/humidity exposure history — stored in passive RFID tags can be collected when a reader or interrogator is nearby. In contrast, a low-power active RFID tag continuously transmits this data to readers or interrogators from a longer distance. Passive RFID tags inherently pose no risk to aircraft systems, but the designs of low-power active tags have to pass safety tests before they can be used aboard aircraft.
“If you have an RFID tag installed on every life vest on the airplane, a maintenance technician could walk through with a reader,” Shaver said. “In just about the time it would take to walk from the front to the back of the airplane, he or she could not only get an accurate count … but also could collect information like expiration date, [model] number and infant vs. adult type.”
Comprehensive testing addresses any radio frequency interference, fire or crashworthiness issues. Airlines ultimately are responsible for allowing any RFID device or system aboard a flight, however, so the FAA urges them to proactively mitigate risks. For example, an airline’s RFID tags must maintain accurate, authentic, uncorrupted and up-to-date data because of the safety of life implications. “Because we want to make sure that the tag stays attached, the AC also has instructions for continued airworthiness,” he said.