Business Aviation Insider

Bookmark and Share
Click to return to the Business Aviation Insider, September/October 2012

Online Extra

Discipline, Proper Procedures Key to Reducing NAT Operational Errors

Even after the notable technological improvements to in-cockpit navigation and communications systems over the past 20 years, navigational errors when traversing the airspace over the North Atlantic (NAT) remain a matter of concern for pilots and air traffic controllers, as such errors often result in the loss of separation between aircraft. While even the most routine transatlantic flight may require a seemingly daunting series of complex tasks to be successfully completed, industry experts agree that the most effective way to mitigate these risks is deceptively simple.

"What really stands out to me is how often crews fly the filed flight plan, and not the clearances given to them by air traffic control," said Peter Ingleton, International Business Aviation Council (IBAC) director for liaison to the International Civil Aviation Organization (ICAO). "Should the initial oceanic clearance be subsequently revised by Air Traffic Control, it is also essential that the flightcrew correctly enter and cross check the revised clearance. Failure to do so may well lead to a significant navigation error."

Such errors are common among both commercial airline and general aviation pilots operating in the NAT, though a disproportionately high number of incidents stem from the private operator side. "On a relative basis, the performance leaves much room for improvement," Ingleton said. "Non-airline traffic comprises between 6 to 7 percent of overall traffic in the NAT, but that segment contributes considerably more deviations on a relative basis than the other 93 percent."

IBAC is among the international aviation organizations that are members of ICAO's North Atlantic Systems Planning Group (NAT SPG), which regularly investigates navigational errors in the region, and has published a series of North Atlantic Operations Bulletins and other helpful guidance documents on the subject. These include an extremely thorough checklist detailing what steps should be followed at each phase and transition of a North Atlantic flight plan.

"This information is just a few clicks away," Ingleton said. "There are no barriers for operators and flight crews to acquire this information, just in assimilating it and applying it. Even after the proper training, the use of a checklist helps to bring a pilot's recollection of those procedures forward."

While these checklists are extremely thorough when viewed as a whole, each individual step is comparatively simple. "There's nothing magical or particularly difficult about any of the items on the checklist," said Paul Stinebring, the current IBAC representative to the Implementation Management Group of the NAT SPG. "I believe the biggest issue is one of complacency. To some extent, these procedures are so basic and simple that crews don't give them the attention or discipline they deserve."

One Deviation Often Leads to Another

There are three ways that separation between aircraft may be compromised: lateral deviations, longitudinal (or horizontal) deviations and vertical (altitude) deviations. "The largest number of deviations falls in the altitude deviations category," explained Dave Stohr, president of ATI and a former IBAC representative on the NAT SPG. "Assigned altitude deviations are scrutinized not only based on how far off altitude an aircraft is, but for how long the aircraft was off altitude."

Altitude deviations often lead to other issues, as well. "Loss of longitudinal separation does occur and many times it is associated with an assigned altitude deviation in that an aircraft climbs or descends without clearance," Stohr continued. "And it does not have the requisite longitudinal separation from other aircraft operating on the same route and altitude to which the aircraft has climbed or descended to. Loss of lateral separation between aircraft based on gross navigational errors is still prevalent, but for the most part static in numbers.

Like Ingleton, Stohr believes consistent use of checklists would go a long way toward reducing these errors. "Loss in lateral separation is commonly an error that occurs when the crew loads the flight plan into FMS. This commonly happens after a crew has received an oceanic re-route," he noted. "Statistics in the North Atlantic region show that 80 percent of all gross navigational errors occur after a crew receives an oceanic re-route."

Has Technology Increased Likelihood for Errors?

Stinebring noted an interesting correlation between the level of technology available to pilots and recent increases of separation errors. "Compared with today's technology, something as simple as noting your position on a plotting chart seems a little old-fashioned, but effective," he said. "It's much easier to use the flight management system [FMS], which will take you wherever you tell it to go, and it looks perfect. The downside, of course, is if you've entered the wrong data, the FMS will take you to the wrong place just as well.

"I believe the biggest potential for error lies in a general lack of discipline in developing a master route log that is completed and updated with ATC clearances, rather than the flight plan," Stinebring added. "The key is to have well-documented procedures in place, and the discipline to follow them."

Once again, all three men stressed the importance of following the proper procedure to the letter in order to reduce the risk of committing an operational error in the NAT. "It is incumbent upon crews to be knowledgeable on procedures and to utilize good standard operating procedures to mitigate the possibility of committing errors," Stohr said.

"If people operate by the book, chances are they will have a happy flight with greatly reduced chances for committing operational errors," Ingleton concluded.

Return to Table of Contents