New tools exist to prevent those accidents that most worry safety experts. At the European Aviation Safety Seminar in Barcelona, Spain, in mid-March, speakers invited by the Flight Safety Foundation identified new trends in air safety, suggested solutions and proposed innovative tools for some–often underestimated–issues, including birdstrikes, which might increase in number; ramp accidents (more costly and more dangerous than previously thought); controlled flight into terrain (CFIT), which will probably remain a major cause of accidents in the near future; pilot error involving crosswind takeoff or landing; and, the increasing incidence of pilots’ rolling in the wrong direction when attempting an unusual-attitude recovery. Accident prevention methods and tool kits, new ground equipment and cockpit instruments were presented to combat these persistent pitfalls.
Wildlife strikes are increasingly worrying safety specialists, since conditions are ripe for their frequency to increase. In addition, certification requirements appear insufficient for airframes and engines to withstand the impact of what are likely to become more frequent collisions with large birds or flocks of birds. Birdstrikes already cost airlines an estimated $1.2 billion per year worldwide. More important, these encounters claimed the lives of at least 192 people and destroyed 140 civil and military aircraft between 1988 and last year.
Among the factors that increase the risk are increasing populations of birds and large mammals such as deer and coyotes. “Highly successful programs funded by governmental organizations during the past 30 years, coupled with land-use changes, have resulted in dramatic increases in the populations of many wildlife species in North America and Europe,” said Richard Dolbeer, the U.S. Department of Agriculture’s co-coordinator for wildlife hazards at airports. For example, 24 of the 36 largest (heavier than four pounds) bird species in North America have shown significant population increases in the past 30 years, while only three species have shown declines. These large birds exceed the size standard under which airliners and, above all, their engines are certified.
Species whose populations have increased at least fourfold in the past 30 years in North America include Canada geese, brown pelicans, sandhill cranes, bald eagles, snow geese and double-crested cormorants. Many of these species have adapted to living in urban environments, including airports. Additionally, birds and other wildlife are less able to detect and avoid today’s quiet turbofans, compared with older, noisier aircraft.
Some 90 percent of hull losses took place on airports–and the airports involved can be considered liable, Dolbeer emphasized. For example, in Italy in June 1989, a BAE 146 operated by TNT Air Cargo departing Genoa Airport at night flew through a flock of gulls at rotation. The pilot managed to return the severely injured aircraft back to the airfield with three engines damaged. The carrier sued a number of parties. After 11 years of litigation, the Civil Court of Genoa in 2001 awarded TNT $2 million in compensation. Liability was assigned as 50 percent to the Ministry of Transport, 30 percent to the private company operating the airport and 20 percent to the port authority. Dolbeer concluded that airports must implement policies to reduce the risk.
The foundation of risk reduction is the management of habitat on or near airports to minimize the food, water and shelter that hazardous wildlife seeks. Professionals such as biologists must be brought in, Dolbeer noted, because only they can work adequately on habitat modification, non-lethal dispersal, live traps and relocation or destruction of animals. “Some U.S. airports have drastically reduced the number of birdstrikes thanks to a shooting program,” Dolbeer said.
Since last November, the International Civil Aviation Organization (ICAO) has put in effect new standards. Every airport should take a three-step action. First, it should assess the risk posed by wildlife. Next, it should develop a wildlife hazard-management plan. “For example, it should define actions such as grass mowing [to make the airport environment less appealing to birds] and define responsibilities,” Dolbeer advised. Finally, it should work on land use to reduce the presence of attractants near the airport. This can be done through eliminating garbage within five miles of the runways.
The U.S. Department of Agriculture’s representative urged every party involved to take action to minimize the risk. Pilots can play their part by staying below 250 knots below 10,000 feet, especially during bird migratory seasons. “Aircraft speed is more critical than bird size in determining damage,” Dolbeer pointed out. Operators should report all strikes, since databases are necessary to provide a scientific foundation for methods to reduce the risk. And Europe’s civil aviation authority (currently the Joint Aviation Authorities but soon the European Aviation Safety Agency), should incorporate specific standards for bird-hazard management at airports, following what has been done by the FAA and Transport Canada.
Last, but not least, current certification standards do not address the wildlife ingestion dangers. Certification does not take into account the risk of a multiple-engine ingestion as testing call for only a single bird ingestion. “And the engine is not even required to continue to run, just to be safely shut down,” Dolbeer said.
Some issues are wrongly considered as a cost of doing business. This is largely the case for ramp damage. According to Bob Vandel, the Flight Safety Foundation’s executive vice president, the huge cost of ground incidents for operators and, more important, the number of injuries (some fatal) they cause, should urge everyone in the industry to work to improve the situation. Hence the Flight Safety Foundation’s apron-damage reduction program.
“On January 19, 2003, an Airbus A319 was being moved from a parking area to a gate when it hit the jetway. Six apron workers were injured. The jetway was extensively damaged. On the A319, the gear collapsed and an engine was damaged,” Vandel stated. An example of a ground accident that caused the death of a worker happened last September 12, when a DC-9 received minor damage when it was struck by a pushback tug. The airplane was at the gate with passengers boarding. The tug driver was standing, trying to attach the bar to the aircraft directly from the tug. He put his foot on the accelerator and, trapped between the tug and the airplane, he was crushed to death.
“Human error is the primary cause of apron damage,” Vandel stated. Solutions need to be data-driven, systemic and positive in their cost-benefit ratio, he continued.
Statistically, any airline operating more than 100 aircraft can expect on average to have one of its aircraft in the hangar undergoing ramp damage repairs every day. These incidents cost the airlines $4 billion annually. They claim an additional $1 billion to business aviation, Vandel pointed out. And the effect on ground equipment and airport facilities is still undetermined.
Ground-accident statistics shed a new light on the safety of employees working on the ramp. While the industry has worked hard for decades to make air transport one of the safest (if not the safest) means of transportation, safety figures for those on the ground are less impressive. With 13.6 total recordable injuries/illness per 100 employees, the airline industry is far from being a role model. Even the lumber industry, which is perceived to be more dangerous, has a better record, Vandel pointed out. Such industries, including chemicals, have focused on improvements.
One might think that insurance covers the cost of ground accident damage, but this assumption is generally wrong, Vandel demonstrated. One airline has found that each ground-damage event costs it an average of $250,000–well below its deductible limit. In fact, only one out of 274 ramp-rash events at this airline met the insurance deductible, leaving the carrier fully responsible for the repair cost in 273 mishaps.
The FSF has developed its ground-accident prevention program using the CFIT/ALAR (approach and landing accidents reduction) model. The program’s structure is relatively conventional. It starts with data collection and analysis, and continues with identification of solutions and implementation of best practices before results assessment. Several teams have been formed, including a steering team and others in charge of apron facilities; equipment and operations; data analysis; education and training; management and leadership practices; and industry awareness. For example, the second working team has to identify apron facilities, equipment and operational practices that improve safety. Its members also have to assess and develop enhancements to reduce ground accidents.
Vandel said automation is a promising solution. Indal Technologies, a Mississauga, Ontario-based company, offers an automatic jetway. It is able to dock the jetway to an aircraft door without human control. Statistics show that 14 percent of incidents that damage aircraft are related to jetways. Botched maneuvering of jetways, catering vehicles and unloading trucks is the top cause of apron damage.
“Automation in all three areas would translate into $1.4 billion in annual savings,” Vandel estimated.
Banishing the CFIT Scourge
Still high on the foundation’s priority list is CFIT. “While there have been many advances in aircraft technology and operating procedures during recent years, the accident rate for CFIT has not shown any marked change,” warned Dan Gurney, who retired from BAE Systems as head of flight safety. The occurrence rate of these accidents is approximately one CFIT accident per year per 1,000 aircraft in service. In Europe, that translates into a potential of one accident per year. Gurney is in favor of an automatic yoke pull linked to EGPWS warnings.
He detailed four CFIT crashes that happened in recent years. The most striking was that of a BAE 146 that hit terrain in Melilla, a Spanish enclave surrounded by Moroccan territory. The crew had flown the route between Malaga, Spain, and Melilla often. The flight path was a straight track, with clear weather most of the time.
However, their habit of making a straight-in approach was flawed in two ways. First, the crew assumed wrongly that the required overflight permission had always been granted by Morocco. And in visual conditions, the crews just ignored the GPWS (EGPWS was not fitted on the BAE 146) alerts that often occurred, Gurney told the seminar attendees.
On the day of the accident, coastal fog and low cloud over the sea partly obscured the mountain range along the coast. In IMC, the flight path should be around the headland, maintaining 3,500 feet before positioning for a nonprecision approach. The latter was time consuming, and crews did not like it, Gurney said. A factor was also peer pressure–the aircraft behind was asking whether a visual approach was possible.
The crew convinced themselves that they could see the coastline. Apparently, it was not the coastline and their choice for a flight path was flawed. The captain continued in level flight at 800 feet, well below the minimum safe altitude (MSA).
There was a GPWS warning, but no adequate pull up on the controls. The crew did not react correctly, Gurney noted, since they used the autopilot pitch mode to pull up, making the pitch change very gradual.
The aircraft hit a 1,000-foot mountain 120 feet below the summit. “This is a major training issue,” Gurney said. After the investigation, 12 training captains flew the accident flight path in a simulator. They knew that they were about to be tested with a GPWS alarm. They all reacted to the warning, but half of them did not clear the mountain top. They did not know “how” to pull up or they had not previously experienced the sensation of the aircraft pitching up quickly.
“This alone supports the need for an automatic pull up after an EGPWS warning,” Gurney asserted. “I doubt any pilot would counter-command [such] an automatic pull-up. Pilots should welcome an automatic pull up because it will convince them that their [belated] pull-up decision is the right thing to do.”
The Flight Safety Foundation has long worked on CFIT prevention. The FSF CFIT/ALAR tool kit contains a risk-assessment tool and CFIT checklist for personal and organizational audits. The checklist asks questions: What are the operating hazards and risks? Are the facilities good enough? Is the aircraft equipment sufficient? The answers result in a rating that should help an operator to determine if and where action is required to reduce the risk of CFIT.
“Airmanship is a skill–it can be trained, it can be checked and it can be improved,” Gurney emphasized. Notably, he insisted that “it is important to select the relevant skills to be proficient in–for example, the physical skill to pull up or go around.
Non-physical skills are also required for communication and interaction within crews, teams or groups and, of course, among authorities and countries.” However, as situational awareness is a consistent factor in CFIT accidents, there are still few resources available to improve it, Gurney acknowledged. Yet he said that he is seeing situational awareness training and other “thinking skills” beginning to appear in CRM and airmanship courses.
‘Install EGPWS Now’
Another factor of CFIT prevention, is equipment. “Install EGPWS now,” Gurney urged the attending operators. “Even Good People Will make an error Someday [EGPWS],” he smiled. He also said crews should practice emergency pull ups. The radio altimeter is a situational-awareness instrument and thus should be used to correlate altitudes with distances to the runway. “Before the final approach fix, the radio altimeter should never be less than 500 feet, and on the final approach the radio altimeter should never be less than 250 feet until after minimum descent altitude [MDA],” Gurney said.
He insisted on zero tolerance for rule breaking. “Just because you have always operated in a particular way does not mean that it is safe,” he said. Refreshing basic knowledge is seen as equally important–“just because you can see the ground does not indicate that it is safe to descend.”
Finally, Gurney suggested involving the crews as much as possible in procedure making. “Crew-induced changes are more likely to be followed,” he said.
Don’t Have a Bad Altitude
Again regarding CFIT, Ratan Khatwa, a Honeywell expert in flight-deck human factors, brought “geometric altitude” to the audience’s attention. A GPS altitude blended with multiple altitude sources, this computed figure can be seen as the true altitude of the aircraft, Khatwa said. Hence, it helps avoid altimetry errors, which “are suspected in 20 percent of large CFIT occurrences between 1988 and 1997,” he noted.
Common errors on altimeters include, among others, misreading, mis-setting, ignoring an unexpected low setting in favor of a setting that seemed more appropriate and nonstandard atmosphere. In extreme temperatures, the indicated altitude can be several hundred feet higher or lower than the real one. Until recently, the primary source for the EGPWS was the corrected barometric altitude. So barometric altitude errors can reduce TAWS effectiveness, Khatwa emphasized.
Fortunately, basic GPWS functions using radio altitude were retained on the EGPWS.
Khatwa gave the example of an MD-80 inbound to Kewlona, B.C., Canada, in January 1988. The temperature was very cold (-30 degrees C), and the aircraft was in level flight in IMC at 6,300 feet indicated. In fact, there was a 900-foot error. Thanks to the radio altimeter, the GPWS issued a warning and the pilot pulled up, clearing a mountain top by some 150 feet. With geometric altitude, the terrain awareness display (TAD) would have shown the pilot a real picture of the situation sooner.
To prove the superiority of geometric altitude, Honeywell conducted tests with three groups of pilots. The first group used a TAD with a barometric altitude reference. The second used a TAD with a geometric altitude reference. The third used the same as the second but also had a digital readout of the geometric altitude. Eight scenarios were presented to each pilot, including normal and abnormal conditions–for example, QNH error or nonstandard atmosphere.
Results showed that pilots who used the geometric altitude made better decisions. The display of geometric altitude allowed a higher detection rate for altitude anomalies. It also accelerated anomaly-detection time. Last, but not least, pilots presented with a barometric altitude terrain display were overconfident.
“Incorrect mental model is a key factor in CFIT accidents,” Khatwa recalled. During the experiment debriefing, numerous subjects admitted that they did not consider the effects of temperature and pressure on altimetry during the evaluation. “This is a disturbing revelation,” Khatwa noted. He expected large temperature deviations from standard and extreme altimeter settings to heighten test-subject awareness and prompt further questioning of conditions.
EGPWS manufactured since 1998 has used geometric altitude. For older units, Honeywell offers a free software update. Khatwa urged all the operators without an up-to-date EGPWS to have the software installed. A geometric altitude readout is already available on GA/business aircraft and helicopters. “We are still discussing with the regulatory authorities the possibility of providing a geometric altitude display on large transport aircraft,” Khatwa told AIN.
Although its use improves safety, geometric altitude is not designed for navigation, Khatwa cautioned: “ATC and aircraft flying need a common reference; this reference is the barometric altitude.”
Foes Join Forces on Crosswind Guidelines
In an unusual teaming, Boeing and Airbus joined forces to encourage pilots to follow crosswind guidelines. John Scully, an Airbus line assistance manager, and Dave Carbaugh, Boeing chief pilot for operations safety, said their purpose was “to have the audience leave with an improved understanding of crosswind guidelines and crosswind values given by the manufacturer.” They mentioned a number of errors that can easily be avoided if the pilot is made aware of better methods.
Carbaugh started to quantify the amount of pressure needed on the yoke to ensure nosewheel effectiveness. “It is very common, when we observe customers in training or flight operations, to see pilots make too large a forward input during the initial phase of takeoff or during the landing roll. All that is needed is light forward pressure on the control column during the initial phase
of the takeoff roll (below approximately 80 knots), which will increase nosewheel-steering effective- ness. Above 80 knots, relax the forward control column pressure to the neutral position,” he said.
Regarding aileron movement, Carbaugh endeavored to answer a frequently asked question. “Often customers ask, ‘Do I start with full aileron [yoke deflection] into the wind or yoke level?’ First off, large inputs of aileron into the wind result in spoiler deployment, which results in less lift, more drag and reduced performance during takeoff. Aerodynamic forces are not very evident at low groundspeed.
“Starting with a moderate amount of aileron into the wind is an acceptable technique. How much is moderate? No more than 50-percent wheel throw. As the airplane accelerates and flight controls become effective, use just enough aileron to keep the wings level. Normally, you can anticipate reducing some of the aileron [wing low] into the wind as the flight controls become more effective as the airplane accelerates,” he said.
Carbaugh insisted that the tiller should not be used past taxi speed. “Except for a few classic 747s that require the pilot to maintain a hand on the tiller during takeoff,” use of the tiller past taxi speed can invite a pilot-induced oscillation, he said.
Scully advised: “Do not try to align the airplane on the upwind side; maintain the centerline with rudder-pedal steering and rudder.” He added that rotation should be avoided during a gust. “If a gust is experienced near VR as indicated by stagnant airspeed or rapid airspeed acceleration, momentarily delay rotation. This slight delay allows the airplane additional time to accelerate through the gust, and the resulting additional airspeed improves the tail-clearance margin,” he said.
About the crab-to-touchdown landing technique, Carbaugh noticed that one of the problems some airlines have had with accidents and incidents using this technique is that the pilot doesn’t lower the wing to prevent drift after touchdown. “In other words, the pilot stops flying the airplane at touchdown,” he lamented. Scully warned that full crab is not recommended for maximum crosswind on Airbus or Boeing Long Beach products.
Sometimes, Carbaugh and Scully observed, there is an attempt to rapidly lower the nose, to slam the nose down onto the runway. This is how a hard nosewheel landing occurs. “The nose should be flown to the runway,” they said, for both manufacturers’ aircraft. Improper alignment is another crosswind technique problem.
“Many accidents result from low-altitude maneuvering coming from poor alignment before reaching the runway threshold,” the speakers said. Pilots also sometimes choose to disregard the airlines’ standard operating procedures, “a human-factors issue.”
Generally speaking, Scully and Carbaugh asserted that crews lack proficiency or experience in crosswind landing. “When observing different airline-training programs, too often we see lessons with light winds. Students are rarely challenged during recurrent training,” they pointed out. “Although most airlines encourage the use of the autopilot, crews should also be encouraged to fly the airplane manually. This improves proficiency, as well as confidence levels, when a situation comes up that requires a manual landing in strong crosswinds,” Scully advised.
On a Roll for Upset Recovery
The traditional artificial horizon, with its blue and brown halves, still holds a significant potential for improvement when it comes to unusual-attitude recovery. Boeing’s principal scientist/engineer, Gary Gershzohn, presented an additional symbol called “roll arrow” that might help avoid pilot disorientation. In other words, it would prevent the pilot from rolling in the wrong direction. The roll arrow indicates the shortest route to wings level. It is a different solution from those studied by Canada’s Institute for Aerospace Research (“Hangar Flying,” AIN, January 2004, page 12). According to the Ottawa-based researchers, spatial disorientation causes between 10 and 12 percent of all aviation accidents.
“With existing HUD and PFD designs, it is unlikely that a pilot will always make a successful unusual-attitude recovery,” Gershzohn asserted. He explained that recognition and recovery errors are caused by pilot inability to obtain fast and accurate attitude situational awareness from raw data. The roll-arrow concept is a compromise between raw data and a flight director that helps the pilot determine aircraft attitude and the first control action needed for recovery.
The arrow appears when the bank exceeds 40 degrees and remains until the bank is reduced to 10 degrees. It is attached to the apex of the bank angle pointer and can revolve 360of roll input–the amount of roll input, as well as pitch, thrust and other changes, must be determined by the pilot,” Gershzohn emphasized.
Gershzohn adegrees around the center of the HUD or PFD. It points horizontally, to the right (to command a roll to right) or left (to command a roll to left). “It indicates the directionnd his team conducted several tests on a group of 18 pilots. Without the roll arrow, the proportion of hesitation, bobble (pilot rolled left and right one or more times before determining correct control input) or roll in the wrong direction totaled 32.6 percent. “Wrong direction” alone accounted for 10.4 percent of the observations. With the roll arrow, these figures fell to 3.4 and 2.1 percent, respectively, of the observations. “Errors were reduced by 90 percent,” Gershzohn summarized. Reaction time was also reduced, from a mean 1.30 seconds to 1.05 seconds.
The scientist said he observed that “after initial control inputs, more mental capacity was available to evaluate attitude, airspeed, altitude and configuration and control the aircraft accordingly.”