Surviving the Graveyard Shift

Transcription

1 PROMOTING AERONAUTICAL PROFESSIONALISM & SAFETY Surviving the Graveyard Shift By Frank Colucci Actual accident aircraft was a non-bell product. Photo is for illustration only. The International Helicopter Safety Symposium (IHSS) last November in Fort Worth heard a grim story of fatigue and fatalities from National Transportation Safety Board (NTSB) vice chairman Robert Sumwalt. In June 2009, a New Mexico State Police trooper-turned-chief pilot returned to his helicopter after a full day of working and flying to search for a lost hiker. He launched in daylight and clear weather, landed on a mountaintop outside Santa Fe to search on foot, and took off with the hiker in darkness and Instrument Meteorological Conditions (IMC) only to crash and die with the person he sought to save. The NTSB report on the accident identified the probable cause as the pilot s decision to take off from the mountain landing site on a moonless night in IMC. Significantly, the contributing factors included pilot fatigue, situational stress, self-induced pressure to fly, and a culture that put mission before safety. Among other recommendations, the NTSB called for the New Mexico Department of Public Safety to implement a comprehensive fatigue management program for its State Police aviation section. The Federal Aviation Administration (FAA) now offers fatigue management tools applicable to helicopter pilots and maintainers online at The FAA website and YouTube also host a new cautionary video Grounded. CONTINUED ON PAGE 2 P.O. Box 482 Fort Worth, Texas VOLUME 22 NUMBER HumanAD AIRWORTHINESS DIRECTIVE FOR HUMANS WIRE STRIKE... 4 CHICAGO Police Department... 5 DON BLOOM AWARDED THE WRIGHT BROTHERS MASTER PILOT AWARD... 6 SPEAKING OF SAFETY... 7 AWARDS & RECOGNITIONS... 8

2 Surviving the Graveyard Shift continued from page 1 The 21-minute vignette follows a stressed airline maintenance manager through fatigue awareness counseling and offers some straightforward insights: Proper sleep eight hours a night at least is critical to decision-making and problemsolving ability. Lack of rest impacts communications skills including listening, and hands-on skills such as flying or physical work. Scheduled air carriers are already showing the maintainer-oriented video to pilots, according to Dr. William Johnson, FAA chief scientific and technical advisor for human factors in aircraft maintenance. Dr. Johnson told the IHSS a survey of 50,000 mechanics calculated maintainers average just over five hours sleep per night, less than the recommended eight hours. He advised the audience, We ve got to have the corporate will to change this. The New Mexico State Police accident underscored the hazard of fatigue in aviation operations characterized by unpredictable working hours, long duty cycles, disruptions in daily circadian rhythms, and insufficient sleep. In the 24 hours prior to his accident, the pilot had worked 11 hours 41 minutes and flown 4.5 hours. He returned to duty just three hours after his normal workday ended to fly the search mission, adding another 3 hours 41 minutes of duty time and 1 hour 41 minutes of flight time to a tiring shift. A previous NTSB study noted that pilots made significantly more procedural and tactical decision errors after more than 12 hours awake. An FAA study found accidents more prevalent among pilots who had been on duty for more than 10 hours. The US Naval Safety Center concluded helicopter pilots on duty for more than 10 of the last 24 hours were more likely to be involved in pilot-at-fault accidents. Navy Capt. John Nettleton, a helicopter pilot now the force safety officer for the Commander, Naval Air Forces told the IHSS, If you want to get rich, give me something that can measure fatigue in 30 seconds, like a breathalyzer for fatigue, and I ll solve a lot of problems. Managing Fatigue The physical symptoms of fatigue yawning, nodding-off, slow reaction times, and lack of energy are easy VOLUME 22 NUMBER 3 The HELIPROPS HUMAN A.D. is published by the Training Academy, Bell Helicopter Textron Incorporated, and is distributed free of charge to helicopter operators, owners, flight department managers, mechanics and pilots. The contents do not necessarily reflect official policy and unless stated, should not be construed as regulations or directives. The primary objective of the HELIPROPS program and the HUMAN A.D. is to help reduce human error related accidents. This newsletter stresses professionalism, safety and good aeronautical decision-making. Letters with constructive comments and suggestions are invited. Correspondents should provide name, address and telephone number to: Bell Helicopter Textron Inc. John Williams, HELIPROPS Manager P.O. Box 482, Fort Worth, Texas , fax or the Comment/Feedback link at: RELEASE STATEMENT: For photos or written submissions, please include a brief statement releasing your material to Bell Helicopter for use in the Human AD newsletter. HumanAD AIRWORTHINESS DIRECTIVE FOR HUMANS Sixty-six years ago on 11 October 1946, Bell Aircraft Test Pilot Chalmers Slick Goodlin made the 1st powered flight of the XS-1 at a speed of.79 Mach at 11,000 meters (36,089 feet) as a build up test flight prior to breaking the Sound Barrier. That feat was accomplished by Capt. Charles E. Chuck Yeager on 14 October 1947 at a speed of 1.06 Mach and 13,100 meters (42,979 feet) for over 20 seconds. 2 HELIPROPS VOLUME 22 NUMBER

3 to spot. More subtle and potentially more dangerous in dynamic helicopter operations are the mental symptoms: difficulty concentrating, lapses in attention, failure to anticipate and communicate, forgetfulness, and making mistakes even when performing well-practiced tasks. The emotional symptoms of fatigue including irritability and loss of motivation to perform tasks well further increase risk of aviation accidents. Among the NTSB recommendations for the New Mexico State Police were protected rest periods in line with existing regulations governing Part 121 airlines, and a Fatigue Management System. The Fatigue Management System integrates assessment tools with countermeasures such as scheduling, education, medical screening and treatment, rest environments, and commuting policies. The Fatigue Management System does not replace protected rest periods, but it should be part of the broader Safety Management Systems used by large and small helicopter fleet operators. offers a collection of downloadable tools and resources to build a Fatigue Management System designed for aviation maintainers and adaptable to helicopter pilots. It presents a threepart course developed with input from scientists, the FAA, industry, and labor to teach aviation shift workers how to combat fatigue both on and off the job. The course also covers the causes of fatigue and how to identify symptoms, and addresses sleep basics and ways to prevent or combat fatigue in the operational environment. A website toolbox includes workplace posters and a calendar that remind workers of critical fatigue issues. It has a sleep log that enables users to track their sleep and assess their sleep habits. A Fatigue Risk Assessment Worksheet helps identify when fatigue is a contributing factor to a safety incident. A Return-on- Investment Calculator for Human Factor Interventions gives helicopter operators the business/financial means to compare fatigue management investments with benefits. The website also includes numerous references to regulations, articles and position papers on aviation fatigue. Aviation, including helicopter operations, remains a round-theclock industry with less-than-perfect schedules. Among the resources on the quarterly MX Fatigue Focus newsletter presented Potential Solutions for Fatigue in a Less-Than-Perfect World: Education about fatigue risks and countermeasures is critical to fatigue management. Math models that predict fatigue based on circadian rhythms can identify schedule risk, predict optimal performance times, and help schedule napping or recovery sleep. Planned napping is an effective fatigue countermeasure. Limiting time on task, either by switching tasks or introducing rest breaks, helps counter fatigue. Used in moderation, waking compounds, most commonly caffeine can reduce fatigue despite sleep deprivation. Ongoing analysis by the International Helicopter Safety Team (IHST) confirms that human factors including fatigue play a role in 80% of helicopter accidents. The Bell 525 Relentless super medium transport helicopter will carry 16 passengers in standard configuration and is designed to offer best-in-class capabilities to our customers. It will feature superior payload, range, cabin volumes, and crew visibility. The Bell 525 will be powered by two 1,800 SHP GE engines and include a BAE triply redundant fly-bywire system for repeatable, reliable, and safe operations in austere flight conditions. For more information, go to HELIPROPS VOLUME 22 NUMBER

4 Wire Strike By David Boyd Bell s First HELIPROPS / Human AD Newsletter (Reprinted from Volume 1 Number 4, 1989) 4 HELIPROPS Helicopter aviation possesses certain denominators that are common throughout the envelope of every flight. The foremost being, that a helicopter cannot successfully survive a flight into wires. Likewise, the helicopter pilot is at a significant disadvantage when operating the aircraft at altitudes that may be optimum for the mission, but jeopardize the safety envelope of terrain and obstruction avoidance. The unusual thing about a wire strike is that you hardly ever see the wire until it s too late. And most wire strike fatalities occur in an area where the pilot was most familiar with the topography and its man-made fixtures. Wires are indiscriminate toward the victims they claim. They remain dormant and impersonal, blending with their surroundings. If the sky is blue, they assume the color of gray-blue. If the sky is enshrouded in fog and mist, wires will camouflage themselves into the bleak surrounding conditions. Wires are not respecters of persons. VOLUME 22 NUMBER Bell s first HELIPROPS manager, David Boyd, stands with his father, retired Bell test pilot Ralph Boyd, at the Vietnam Helicopter Pilot s Memorial near Mineral Wells, Texas. David currently is a safety consultant with the oil and gas industry having retired from American Airlines as a Captain. Social status means nothing to a wire. It doesn t care if the CEO is onboard, or you are hurrying to deliver a small child to an emergency care room in the local hospital. But, wires are not alone. They require encouragement and support from accomplices otherwise known as towers. Although somewhat more visible in clear weather, the tower will also play hide-and-seek in low ceiling and fog-laden environments. Now let s be fair. Not all wires are the same. Some are larger and charged to bear the load of responsibility for their existence, whereas others are static and completely on the top of the whole scene. But whatever the case, each carries its own special form of danger and demise to the unsuspecting pilot. So, what do we do about it? Are the answers or solutions or solutions really that simple? First things first; is there a problem? Definitely, Yes. How do we solve the problem? Well, we could either cease helicopter flying or get rid of the wires. Maybe we should bury all wires. If we did, would everyone start having tree strikes? Okay, then what about coloring the wires? Maybe construct all wires to be a standard height above the ground? How about a Wire Strike Alert System (W.S.A.S.)? You ve never heard of this? That s because it s never been invented. And even if it were produced, it would have a circuit breaker that would allow you to take it offline when the alarm noise became too annoying. What about limiting the altitude to which a helicopter could descend above the ground? What would be the

5 limit; 100 or 200 feet? This type of discourse could continue until we are blue in the face and achieving nothing. Sooner or later we must acknowledge the fact that we can institute all the engineering safety designs conceivable, but the bottom line is the judgment of the pilot and operator. Only the pilot can call the shots and rely upon his judgment skills to affirm or negate the use of a helicopter in wire-infested environments. This is a privilege and responsibility that the pilot must exercise. And the wonderful aspect is that the Federal Aviation Administration (FAA) provides every pilot with the authority to control every situation responsibly. Consider for a moment the language in 14 CFR Section 91.3 (a): The pilot in command of an aircraft is directly responsible for and is the final authority as to the operation of that aircraft. Editor s note: the 2011 Federal Aviation Regulations (FARs) have not changed the wording or the location of this Regulation. This regulation is straightforward and void of legalese. It directly addresses the issue of who is in command of the aircraft and who will be responsible for the outcome of a flight. The helicopter pilot loves to fly. But, flying a helicopter safely requires more than stick and rudder skills. It mandates the acceptance of responsibility and exercise of authority. Neither should be abused nor carried to extremes. The key element to all of this is professionalism. The pilot and operator must operate the aircraft in like manner. To do this requires responsible decision-making skills. And judgment as to what to do, when to do it and for how long is a major responsibility and obligation of any pilot. Whether you fly a C-5A or a Bell 47 is of minor concern. Decision making is the same. The responsibility is the same. And the outcome is the same. But how do these issues affect wire strikes? In a single word: judgment. Regulations providing avenues for safe operations exist. But it is the pilot s discretion and judgment to avail him of the benefits and protections they afford. And the idea of implementing and practicing these concepts is the easiest checklist to perform. All you have to do is make this element a part of your operations practices. This same rule of thumb can be applied to EMS (Emergency Medical Services), ENG (electronic news gathering), etc. And have it firmly established that if you get off the beaten path, have a set altitude in mind and climb to it. Helicopter pilots are continually called upon for creative and unique ways to perform mission tasks. To remove or restrict this element of versatility would prevent the helicopter from performing as designed. All we are saying is choose to do it safely the first time. Deciding to fly in close formation with wires is serious business. Stay above them if at all possible and while you are being creative, also utilize your resources of judgment, experience and skill to keep you out of danger. More simply put, make you operation as safe as possible and stay away from wires. Chicago Police Department According to Officer Kuprianczyk, during an observation flight on 1 December 2010 for the memorial service of a fallen Chicago Police Officer, a loud bang was heard coming from the engine compartment area. Following a quick scan of the instruments and maintaining aircraft control, a decision was made by Officer Kuprianczyk and his Tactical Flight Officer (TFO) Cook County Sheriff s Deputy, Anthony Burns, to turn back immediately to their base. However, on short final approach, engine power was lost and an emergency landing had to be made. There was no further damage to the aircraft. Left to Right: Claude Jones, Contract Mechanic, Gary Jet Center; Erik Sharp, Customer Service Engineer, Bell Helicopter; Stan Kuprianczyk, Officer/Pilot, Chicago Police Department; Chuck Hurdleston, Keystone Helicopter; Harry Vergis, Bell Helicopter. HELIPROPS VOLUME 22 NUMBER

6 Don Bloom Awarded the Wright Brothers Master Pilot Award The Federal Aviation Administration (FAA) recognizes pilots who have demonstrated professionalism, skill, and aviation expertise by maintaining safe operations for 50 or more years by awarding the Wright Brothers Master Pilot Award. Recipients receive an FAA award certificate, a lapel pin and are recognized in the Wright Brothers Master Pilot Award Roll of Honor, located online at the FAASafety. gov website. The list of eligibility qualifications is long and the selection process is tedious. Donald Bloom, a retired Bell Helicopter Test Pilot, was nominated and selected to receive this prestigious award. On Monday, November 28, Stephen Norred, an FAA Safety Team Program Manager, presented Don with the Wright Brothers Master Pilot Award at the Bell Helicopter Alliance Training Facility during a customer reception. A large group of Don s fellow pilots and Bell Helicopter Customers were present to witness this momentous occasion. Don joined Bell Helicopter in 1961, spending 24 years in Experimental Flight Test, and accumulating an impressive amount of hours in experimental and development time. Donald Lee Bloom, born in Tulsa, Oklahoma in April 1932, was fascinated with flying from a very young age. Growing up, his bedroom was full of model airplanes hanging from the ceiling. At the age of eight, he listened to the aviation adventures of Hop Harrigan, America s Ace of the Airwaves on the radio. His dream of becoming a pilot was put on the back burner when football became his passion during high school and college. It was during his senior year in college that becoming a pilot became crystal clear to him when, by chance, while walking through the student union building, a US Navy Lieutenant was sitting at a desk with a Fighter Jet Aircraft billboard. Following graduation, he joined the US Navy flight-training program. After his preflight training, Don became a navy cadet, and was commissioned in the US Marine Corps. His first flight as a pilot was in Pensacola, Florida on a beautiful day in October After spending two years flying in the US Marine Corps, he decided that he would like to become a Test Pilot. Don worked as an experimental test pilot for Kaman Aircraft for two years and in November 1961, Bell Helicopter offered Don an experimental test pilot job. He worked for Bell Helicopter as an experimental test pilot and development pilot until he retired in 1990 as a Senior Experimental Test Pilot. Don built up an impressive list of credentials during his career. He flew first flights in the Model 777 (super UH-1D), OH-58A, AH-1J, 206L series, 206B series, 222 and UH-1C. As a Bell Helicopter Engineering Development test pilot, he flew structural demonstrations that were required for Military Approval. He was a project development pilot on the first prototype fighter helicopter, the Bell AH-1G Cobra. Don also piloted structural demonstration test flights on the UH-1C, AH-1J, AH-1S and the UH-58C helicopters. He developed Don Bloom (L), retired Bell Experimental Test Pilot and Tom Wood (R), Bell Helicopter Technical Fellow at the Wright Brothers Master Pilot Award Ceremony. 6 HELIPROPS VOLUME 22 NUMBER

7 high velocity curves for the OH-58A, 206L, 206L-1, 206L-3, 206B, 206B-1, 206B-3, 204B-4 and the UH-1C. In 1984, the Society of Experimental Test Pilots presented the coveted Iven C. Kincheloe Award to Don for his successful investigation into spin phenomena of the OH-58A (later identified as loss of tail rotor effectiveness LTE). He was the first helicopter test pilot to receive this award, joining the ranks of many notable contributors to aviation history. Recipients of this award are displayed at the Smithsonian Air and Space Museum, including astronauts John H. Glenn Jr. and members of the NASA Mercury Program, Neil A. Armstrong and members of his Lunar landing team, Scott Crossfield (North American X-15 Program), and Charles E. Yeager (Bell XS-1 Breaking the Sound Barrier). Don Bloom and Tom Wood, Bell Helicopter Senior Technical Fellow, were recognized in 1984 for developing a new understanding of LTE based on flight investigation for which they received the Howard Hughes Award. This award is given in recognition of an outstanding improvement in fundamental helicopter technology brought to fruition during the preceding calendar year. Don made a significant contribution to understanding and explaining the Loss of Tail Rotor Effectiveness (LTE), said Tom Wood. The results of the flight data and interpretation of the data during 1983 are still taught at Bell s Flight Training Academy today. From his first flight in 1955 through his retirement in 1990, and even today, Don continues to set an example for what the meaning of a Master Pilot is. According to his fellow pilots Don does not fly helicopters, he wears them. It is only fitting that he received the Wright Brothers Master Pilot Award and was recognized for his safe flight operations for more than 50 years. Speaking of Safety Don Bloom Wright Brothers Master Pilot Award First described as a spin phenomenon, it was later termed uncommanded right yaw because the test aircraft was a Bell OH-58A which characteristically spun to the right if the tail rotor malfunctioned. Later, the term uncommanded right yaw was rightfully changed to loss of tail rotor effectiveness or LTE when it was realized that there could be an uncommanded left yaw event with helicopters whose main rotors rotated clockwise. Any single main rotor helicopter can be affected. Now a youthful octogenarian, Don was recognized in ceremonies at the Bell Training Academy in the presence of his family and friends for having been an FAA certified pilot for 50 plus years. There is neither a better recognition nor anyone more deserving than Don Bloom. However you view him, Don is a gentleman and consummate professional who dedicated himself to the betterment of our industry. Well done Don. By John Williams Jwilliams2@bh.com The Number One Cause of Accidents: Human Error It makes good sense to me that if the acknowledged number one cause of helicopter accidents is identified as Human Factors, then I also believe it to be a good idea to learn about that problem area in order to find solutions. There are many good resources for the aviator, mechanic or anyone involved with planning or executing a flight to learn about human factors as they apply to making errors. But, a common mistake by people when asked the question, what is the number one cause of aircraft accidents? is that most will answer, Pilot Error. Certainly, pilots make errors, cause accidents and usually make the front page of newspapers in the process. Less talked about are the errors made by others involved with the flight such as maintenance, dispatching, management or supervision, to name a few. Should you want to learn more, start with three basic human factor areas discussed by aviation safety professionals. They are physiology, psychology and ergonomics. The threat to our industry is real. Fortunately, there are industry and safety organizations dedicated to reducing helicopter accidents. The American Helicopter Society, International (AHS) the International Helicopter Safety Team (IHST) and the Helicopter Association International (HAI) offer courses at their conventions, seminars and on their websites. In the United States the FAA created an entire online program, called the FAA Safety Team or FAAST. The web address for FAA certified pilots and mechanics is Offered are the Wings-Pilot Proficiency Program and AMT-Awards Program for maintenance personnel. Most worldwide civil aviation authorities offer similar safety programs. Wire Strikes David Boyd was the 1st HELIPROPS Manager. The HELIPROPS program concept dates back to the early 1980s when George Powell, now retired (Director of Customer Support Services) saw the need to learn what caused the increase of helicopter accidents and then what could be done to reduce them. Thus, HELIPROPS was born out of the necessity to save lives, machinery and ultimately our industry. The job of organizing the new safety program was given to David Boyd who came to Bell from his safety position with the oil & gas industry. Already a fixed wing pilot, David saw an opportunity to make a safety contribution to the helicopter business and pursue his helicopter certificate too. By coincidence, David s father Ralph was already test pilot at Bell. David s article regarding Wire Strikes highlighted the problem encountered years ago and we can see it remains pertinent today. HELIPROPS VOLUME 22 NUMBER

8 Awards & Recognitions Bell Helicopter Award Programs Many Bell pilots and operators have requested information on what type of Bell Helicopter wings and safety awards are available to them. There are two ways to obtain recognition for pilots who fly Bell helicopters. The first recognition is a Pilot Safety Award issued on the basis of safe flying hours in Bells. The second is a wings award based on th pilot s flight hours in Bell helicopters. It is possible for a pilot to obtain both awards. Bell Flight Time Wings Award The second recognition is for a pilot s Flight time in Bell Helicopters. The Bell Training Academy issues this Certificate of Achievement with a Wings Lapel Pin in increments of 1,000 hours up to 25,000 hours. Example: A pilot with 1,200 hours would receive a certificate indicating their 1,200 flight hours in Bell Helicopters and a Wings Pin with a 1,000 hours on the pin. The next opportunity for a higher award would be at the 2,000 hour mark. This would include the certificate and a Wings Pin with the number 2,000 at the crest. A 25,000 hour pilot would receive the certificate and the Wings Pin that indicates they have 25,000 hours. For the hour level recognition to be awarded, the pilot (or company) must provide the following: Name of pilot as they would like it printed on a certificate, a verified flight time in Bells by either the Chief Pilot or a Company Administrative Official. In the case of an individual pilot making the request, a signed copy of the page in the pilot s log book that verifies the hour level for the wings requested. or mail the documentation proof to John Williams at: jwilliams2@bh.com, or Bell Helicopter Textron Inc., Attn: John Williams, Dept. 9S, P.O. Box 482, Fort Worth, Texas USA. Pilot Safety Award Recognizing an individual pilot for flying safely is far too rare. Most pilots only hear of mistakes made by another pilot in an accident. Bell provides a Pilot Safety Award certificate for hours flown without an accident in a Bell helicopter. This can be achieved in either military or commercial aircraft. The award is given in thousand hour increments to recognize those pilots with a proven commitment and history of safe flying. To apply for this recognition certificate, please send a request letter from the chief pilot, CEO, military commander, or other individual who can confirm how many accident-free flight hours you have flown in Bell helicopters. If you are an individual pilot/owner, you can write the statement yourself. Let us know how you would like the name to appear on the certificate. If you want to include a military rank, you need to indicate that. The award is maintained through the Bell s Flight Safety Department within Bell Engineering; Bill Sarles is the Bell point of contact. His mailing address is: Bell Helicopter Textron Inc., Attn: Bill Sarles, P.O. Box 482 M.S. 1405, Fort Worth, TX USA The pilot s name and safe flight hours are posted on Bell s Flight Safety web page Follow the link to the Heliprops Pilot Safety Award Program. Flight Time Wings and Certificate Recognitions Pilots with Accident Free Filght Time 252nd Presidential Airlift Squadron, Philippine Air Force Pilot s Name Bell Flight Hours Brigadier General Alexander P. Bote 4,000 Colonel Arnold A. Mancita 4,200 Lt. Col. Dennis G. Estrella 1,262 Lt. Col. Pablo E. Rustria 1,489 Lt. Col. Diosdado F.M. Penamante 2,112 Lt. Col. Fermin M. Carangan 2,100 Lt. Col. B. Pasamonte 5,125 Lt. Col. Jesus Nelson B. Morales 2,079 Lt. Col. Noel B. Cadiz 2,214 Major Paulo C. Teodoro 1,441 Major M.A. Consuelo N. Castillo 1,410 Captain Jose Roy C. Magbanua 1,795 Captain Alexon B. Ramos 1,185 Captain Percival C. Macaranas Jr. 1,174 Pacific Western Helicopters, Prince George British Columbia Robert Arsenault 5,000 Stefan Ermair 5,000 Kenneth Knight 22,190 Ulrich Koerner 1,752 John Marsh 10,456 William Oestreich 2,637 James Reed 16,080 David Sjoblom 1,405 Steven Tanaka 1,959 Daniel Widmer 1,087 Erwin Karrer 2,683 Servicio Tecnico Aero de Mexico Gustavo Vigil Diaz 10,000 New Auckland, Australia. Simon Blythe 1,000 Subscription Form n I would like to request a free subscription of the HELIPROPS HUMAN A.D. n I would like to renew my free subscription of the HELIPROPS HUMAN A.D. Subscribe online at NAME TITLE COMPANY ADDRESS CITY/STATE/ZIP/COUNTRY MAIL, FAX, OR TO: Bell Helicopter Textron Inc., John Williams, HELIPROPS Manager, P.O. Box 482, Fort Worth, Texas Fax HELIPROPS@bh.com 8 HELIPROPS VOLUME 22 NUMBER