“Oh, Lord, thy sky is so big and my airplane is so small.” — An aviator's prayer
And when your airplane is over the high seas far from a suitable alternate and something breaks — especially at night or in bad weather — the elements grow to seem immeasurably large and hostile.
But knowing exactly what to do in the oceanic airspace in which you're flying — to have trained for it as well as knowing the International Civil Aviation Organization (ICAO) procedures by rote — will go a long way toward bringing things back into perspective and getting you and your passengers through. Implicit in this, especially in congested airspace like the North Atlantic, is executing the relevant contingency procedure while not endangering other aircraft with hundreds of souls aboard coursing alongside or below you.
That mandate comes with the territory, so to speak, and tends to represent more of a challenge to business and general aviation operators than to the airlines, which ply the oceanic routes and organized track systems on a routine basis and are backed up by significant company infrastructure. Except for the rare flight department that fields its aircraft internationally at least once a month, continuously reinforcing crew knowledge and proficiency in oceanic procedures, the majority of operators of long-range business jets may make an oceanic crossing only a few times a year.
Thus it is incumbent on these cockpit crews to not only be versed in procedural knowledge specific to the area of operation, communications, position reporting protocols and flight plotting, but also be committed to thorough preflight preparation for each mission abroad. When one also considers all the prerequisites ancillary to the flight — required documents, overflight and landing permits, customs and immigration requirements, destination aviation regulations, airport information, noise and curfew ordinances, handling agency coordination, aircraft parking and servicing, security, catering, hotel and ground transportation arrangements, etc. — it's a lot of work for a small operation. While the airlines and big business aviation operations have dedicated dispatching personnel to handle the workload, smaller departments do much of that heavy lifting on their own.
The importance of getting it right comes into focus when one considers that flight crews are responsible for their own surveillance in the non-radar environment that characterizes much of oceanic operations throughout the world. Because air traffic controllers cannot see aircraft when they're 200 sm from shore, a crew's navigation must be precise and the oceanic clearance, flight level and Mach number flown exactly as assigned to assure separation from other aircraft. And if an emergency occurs — say a worst-case scenario like a loss of cabin pressurization or the increasingly rare event of an engine failure — and the aircraft cannot maintain altitude, then the offset from assigned heading and subsequent descent must be flown exactly as stipulated in ICAO oceanic procedures (or the course of action specific to the relevant region or track system).
If cruising in an organized track system or on a diagonal published or random route above a track system, the importance of knowing the location of the tracks is critical in the event the aircraft must descend (or turn around and go back). This situational awareness and the necessity of informing oceanic ATC if a contingency must be executed are mandatory for maintaining safe operations.
Like I-95 at Rush Hour
In the North Atlantic Track System (NATS) alone, the heaviest traveled oceanic sector in the world, 1,200 crossings on average are made every day, 600 in each direction. According to Nat Iyengar, formerly with World Airways and currently a safety pilot in a major corporation's flight department, the amount of traffic encountered in the NATS on a typical crossing has to be seen to be fully appreciated.
“The traffic is so dense that on a clear night you can easily count up to 50 aircraft above, below and on adjacent tracks during your crossing,” he said. “At any given time, the lights of as many as a dozen are visible around you. It's like a six-lane highway: Interstate 95 at rush hour!”
Thus, when an aircraft proceeds out over the North Atlantic, vertical, lateral and longitudinal separation must be precisely maintained for everything to work safely and efficiently. The responsibility for this interaction falls squarely on flight crews (and to a lesser extent on controllers hundreds of miles away).
Depending on projected traffic levels, the NATS consist of as few as four and can exceed 13 parallel tracks, all temporary routes “built” twice a day across North Atlantic airspace, their position determined by prevailing winds. (That is, the tracks are shifted either north or south to take advantage of the most favorable winds.) Eastbound tracks are laid out by Gander Area Control Center (ACC) and apply between 0100 and 0800(at 30 deg. west longitude), their westbound counterparts by Shanwick ACC, applying between 1130 and 1900 UTC (also at 30 deg. west).
Within the track system, traffic flows only one way, depending on the time of day, i.e., easterly at night, westerly during daylight hours. Typically, the “core” tracks will lie within the confines of Gander and Shanwick airspace, but when the system is built up to accommodate peak traffic loads, the northernmost track can nudge into Reykjavik/Shanwick controlled airspace and southernmost into New York/Santa Maria (Azores) territory.
Flight levels on the tracks are separated vertically at 1,000-ft. levels (RVSM was introduced in 1997, the first region in the world to receive it). Eastbound tracks consistently operate between FL 320 and FL 400, while westbound tracks are commonly set between FL 310 and FL 390. Currently, tracks are separated laterally by 1 deg. of latitude at each 10 deg. of longitude (as standard in Minimum Navigation Performance Specification airspace), resulting in distances between tracks varying between 50.5 nm and 60 nm. Meanwhile, longitudinal separation of 10 min. is maintained by assigned Mach number.
Sometime between 2015 and a future date to be determined, separation will be reduced to one-half degree latitude throughout the Organized Track System (OTS) to allow more capacity (i.e., additional tracks), ratcheting down distance between adjacent tracks to between 25.25 nm and 30 nm — and demanding even tighter adherence to procedures and required navigation performance. Likewise, longitudinal separation is scheduled to be reduced by 50% to 5 min. within the same time frame. We'll elaborate more on these changes and the equipage mandate necessary to meet them later on in this report. (But understand now that there is a big change on the near horizon in how aircraft will need to be equipped in order to operate on the NATS and other North Atlantic MNPS airspace.)
Out in the Pacific region on the Pacific Organized Track System (PACOTS), lateral separation between tracks has been reduced from 100 nm to 50 nm for aircraft operating between FL 290 and FL 410 with navigation equipment certified to RNP-10 accuracy and 30 nm for those meeting the RNP-4 standard plus equipage and approval for Controller Pilot Data Link Communication (CPDLC) and Automatic Dependent Surveillance-Contract (ADS-C).
The PACOTS are generally laid out south of the Northern Pacific published route structure, but depending on winds they may merge (i.e., if winds require that the PACOTS be moved north). Also traversing the vast Pacific Ocean are the Central Pacific published routes between the U.S. West Coast and Hawaii and the Southern Pacific published routes between the West Coast and New Zealand and Australia. Finally, an organized track system runs between Japan and Hawaii but is rarely traversed by business aviation.
A related issue that especially concerns business aviation operators flying in oceanic airspace, especially on the track systems, is the ongoing tally of gross navigation errors (GNEs) and large height deviations (LHDs) attributed to general aviation. Per capita, or as a percentage of usage, general aviation error totals have shown little improvement over the last decade. This is a particular concern to both regulators and the business aviation community, given the forthcoming reduction in oceanic separation standards.
As the International Business Aviation Council's Peter Ingleton, who directs liaison between IBAC and ICAO, points out, ignorance of oceanic procedures and responsibilities on the part of operators is no excuse.
“There is a wealth of material on the ICAO website,” Ingleton said. “In terms of preparing for the flight, all the material is there — the information is available. After that it becomes a question of professionalism and vigilance.” Nevertheless, tallies of GNEs and LHDs, especially in the NATS, continue to remain fairly constant despite attempts through the years to educate business aviation operators of the criticality of remaining true to the assigned clearance stipulating track heading, flight level and Mach number.
(This is not to say that airline crews or even controllers don't make operational mistakes — the vast majority of which are committed by the airlines, by far the largest users of the track system — but it is generally conceded that especially business aviation operators need to do better, as the stakes for incompetence are so high.) “What you find in both airline and general aviation operations is that the preponderance of errors occurs because the flight crew follows the flight plan instead of the clearance — and that just keeps popping up,” Ingleton said.
When Something Happens
Which brings us to our core discussion of oceanic emergency procedures, or in controller-speak, “contingencies.” A contingency is a procedure, and in the oceanic operations context, those with which pilots should be knowledgeable and adept address emergencies, weather diversions, loss of communications and loss of long-range navigation capability. Note that there are general ICAO contingencies and, from those, others that are tailored for and apply only to specific regions and OTSes.
When something happens that is sufficiently serious to warrant a departure from the assigned route or track, the procedure is identical — a fact that not all pilots realize, as an assumption widely exists that the contingency applies only within an OTS. “It makes no difference whether you're on the tracks or not, the contingency procedures are the same,” affirmed Dave Stohr, president of Air Training International, headquartered near Dallas. “The only place where there is a difference is operating above MNPS-RNP airspace in the North Atlantic region and having to descend through it. Other than that, the ICAO procedure is the same in each type of airspace.”
If possible—that is, if the emergency does not require immediate action (e.g., an explosive decompression)—the first task, no matter where you are, is to coordinate with ATC and obtain a revised clearance. “Due to communication or time constraints, you may not be able to do that,” Stohr said. “If you cannot take action with a revised clearance, the flight crew should then turn 45 deg. off the cleared route of flight. Whether left or right is the pilot's decision.” Obviously, if operating on an outside track of an OTS, the turn should be made away from the track system, on a published route, away from the route system.
The crew is then to establish a 15-nm offset from the cleared route of flight, flying parallel to the tracks, either in the same direction of flow or the opposite direction, if it is necessary to turn back and the turn can be made without trespassing on adjacent tracks. As stated in the ICAO oceanic procedures, the aircraft is to be placed on an offset track “where other aircraft are least likely to be.”
“If the aircraft can maintain altitude,” Stohr explained, “when the aircraft is 10 nm off the cleared route of flight, the crew should then climb or descend as able, 500 ft. if at FL 410 and below or 1,000 ft. if operating above FL 410. If the nature of the problem is such that the aircraft cannot maintain altitude, then the pilot should minimize descent to the maximum possible while achieving separation from the cleared route of flight.” Somewhere in this process, if communication is possible, the crew should advise ATC of the aircraft type and nature of the problem.
Crews should also be knowledgeable of the drift-down procedure for their aircraft type and have practiced it in a simulator. “The operating manuals for today's business jets describe drift-down procedures, where you trade altitude for range or distance,” Stohr continued. “This enables the flight crew to minimize descent while clearing traffic for route of flight. You have to take into consideration the aircraft below you.” This includes those that might be flying the Standard Lateral Offset Procedure (SLOP) 1 or 2 nm to the right of their assigned track. While all the traffic is going in the same direction in an OTS, on some random routes, it's bidirectional at odd and even flight levels, another justification for the 45-deg. offset procedure if descending.
Another detail demanding attention is to broadcast on 121.5 or 123.45 MHz the aircraft identification, flight level, position and intentions to alert other aircraft in the vicinity. And based on your calculated equal-time point (ETP) and assigned clearance (not the flight plan), decide early in the flight where you will go if a diversion is necessary. (See “Be Proactive” sidebar for a sample contingency checklist.)
If You Have to Turn Back
Turn-backs in or above an OTS require special consideration. Iyengar, who captains aChallenger 605, and in another job also flew left seat in a Gulfstream 550 on many Atlantic transits, advises, “Always have a contingency plan and really know it in the event you're above the track system and have an emergency and have to descend. Know ahead of time which way you will have to turn if you need to go back.
“In business aviation,” he continued, “many times we will fly across the Atlantic on a random route above the tracks, often against the traffic. So you have to be very aware of where the tracks are and have a plan on which way you will turn if you have a problem. The worst case scenario is that you will be flying diagonally across the tracks above FL 410 and have a problem that needs you to do either an emergency descent or a drift-down, and so you really need to know where the tracks are because you are going to want to go down between them. So always know where you are relative to them.”
Stohr related a couple of tales of business aviation flight crews who were less than careful in managing their descents after experiencing emergencies. “A few years ago a business jet developed a pressurization problem requiring a descent. The crew proceeded direct Shannon and, in cutting across and descending through the tracks, caused a TCAS traffic advisory with two airliners and a resolution advisory for a third airliner.
“Another business jet developed a pressurization problem, as well,” he continued, “and the crew turned to a heading of 015 and descended, causing TCAS advisories for several airliners. Contingencies are written so that they will put aircraft in a position where they are least likely to conflict with other aircraft, based on the oceanic structure.” The moral is simple: Fly them as they're intended to be flown.
Iyengar “highly recommends” that when flight crews are receiving simulator training, to practice the contingency scenario and see how their aircraft perform and how they drift down. “Believe me, you will be surprised at how much lateral difference it takes to make a 180-deg. turn in case you have to go back to your origin or to reach your closest alternate. In the Gulfstream 550, depending on your weight, it will take 15 to 18 nm to make that turn.”
He even provided a simulator training scenario, in this case for the G550: FL 430, ISA conditions, Mach 0.83, 66,000 lb. “With one engine failed and the other at full power, drift-down took 55 sec. to slow to Mach 0.78 and 31,900 ft., and 4 min. and 20 mi. to make a 180-deg. turn in the descent. At FL 290, it took 3.4 min. and 18 mi. to make the 180-deg. turn. If you are sufficiently high above the tracks, you have to immediately make the turn before descending through the tracks or, if not, you must descend through and below the track structure before making the turn.”
So, based on your simulator experience, compile a plan of how you would pull off this maneuver if you ever had to do it. “You have to be on the ball and know what your plan will be,” Iyengar said. Especially if having to descend from a random route above the tracks, “you are penetrating into a structure where there are a lot of other aircraft.”
We ran this by trainer Stohr, who stressed, “If you need to go back, make sure you can make the turn within 15 nm; however, if you can't and overshoot the offset, continue the turn beyond 180 deg. to intercept it.” Thus the turn off track would be immediately initiated and maintained until an intercept heading back to the 15-nm offset has been established. “The procedure specifically states that, based on the performance of the aircraft the 15-nm offset is expected to be overshot,” Stohr explained. If operating within [the forthcoming] 25-nm lateral separation on the NATS, “extreme caution” must be exercised regarding now-opposite direction traffic on the adjacent track. Stohr also recommended that a climb or descent should be completed preferably before approaching within 10 nm of any adjacent track.
OK, so now you're backtracking. How are you going to navigate? “Invert the flight plan, if you have to reverse,” Stohr suggested. “Use the FMS, if the one in your airplane has the capability to invert, or preload a reverse flight plan before the flight.” Note: If you've been able to contact ATC to receive an amended clearance, then fly the new clearance.
Space prohibits a discussion of loss of communications and navigation and weather-deviation procedures, and readers are referred to ICAO and regional documents for full descriptions. The accompanying sidebar describes how to obtain these references plus relevant NATS documents supporting media.
How Common Are Diversions?
An examination of North Atlantic MNPS turn-back and diversion data from 2006 through July 2009 reflects the following:
Causes of diversions and turn-backs included medical emergencies, smoke in the cockpit, fuel pressure, hydraulic problems, engine shutdown, low fuel, navigation system failure, cargo fire, generator failure and destination weather.
Diversions and turn-backs in MNPS airspace occurred at a rate of approximately 12 per month through the period.
Approximately two to three times per month, a pilot was required to use published contingency procedures to make at least the initial maneuver to start a diversion or turn-back.
“The last time that I went through the data,” a retired employee of a major aviation regulatory agency reported, “it shows that in the North Atlantic region, an emergency where an aircraft has to depart track or flight level either with or without ATC clearance occurs about 145 times per year. So, this is not uncommon.”
However, a surprising discovery that emerged from the regulator's study was the number of medical emergencies requiring a diversion to an alternate with medical facilities, usually Iceland or the Azores. “Often, this means having to turn around,” he said. “So you have to be aware that this is not uncommon where you have to move the airplane off the assigned course, either obtaining a clearance to do so, or if unable, falling back on contingency procedures designed to put the airplane where it is less likely to encounter another airplane.”
Another common diversion results from en route weather. “The other thing in the same vein, of course — a regular occurrence in the West Atlantic, Gulf of Mexico and certain areas of the Pacific — is where the aircraft has to maneuver around convective weather,” the former regulator said. “Same deal: First stipulation is to get ahold of ATC, obtain a clearance and if you can't, revert to weather deviation procedures.”
As already noted, some big changes are in the works regarding reduced separation standards on the NATS along with a commensurate avionics equipage mandate necessary to accommodate them. The precedent for this actually occurred in Pacific MNPS/OTS airspace shortly after the millennium, when lateral separation was reduced from 100 nm to 50 nm. “The standards for that are based on enhanced aircraft navigation, communication and surveillance capabilities,” the former regulator, who has played a role in developing oceanic procedures, said.
Currently, an operational trial is in progress within the Gander and Shanwick Flight Information Regions (FIRs) testing 5-min. longitudinal separation, reduced from 10 min. The trial, scheduled to run either until March 2014 or until 5-min. separation is approved by ICAO, requires equipage with GNSS, CPDLC and ADS-C with an 18-min. reporting capability — in other words, the tripartite components of FANS 1/A supporting communication, navigation and surveillance (CNS), as hammered out by ICAO signatories in the 1980s and in increasing use over both the Atlantic and Pacific oceans by the airlines and a handful of business jets.
In January 2012, a proposal to amend North Atlantic procedures in phases based on a mandate to require FANS 1/A equipage was approved by the ICAO Council. Groundwork for this will be laid with a second operational trial beginning Feb. 7, 2013, confined to two core tracks of the NATS between FL 360 and FL 390 reserved exclusively for aircraft equipped with the FANS package. On Feb. 5, 2015, this will be expanded to include so-far undetermined portions of North Atlantic MNPS airspace (outside the NATS), again only for FANS-equipped aircraft. Note that up to this point, these trials involve only equipage and not separation reductions.
Finally, lateral separation reduction from 60 nm to 25 nm by applying one-half degree spacing on the two core NATS tracks will commence with Phase 1 sometime in 2015 for FANS-equipped aircraft with RNP-4 approval. This will be followed by Phases 2 and 3, when both reduced lateral and longitudinal separation are extended, respectively, (1) throughout the entire NATS and (2) in all MNPS airspace in the North Atlantic region at dates yet to be determined (but assumed to fall before 2020).
At these points — or simultaneously, if the North Atlantic Systems Planning Group elects to implement Phases 2 and 3 at the same time, an option under consideration — all aircraft will be required to be FANS 1/A-equipped to operate on the OTS and published routes in the region.
Consider, too, the heightened responsibility that will be imposed on flight crews for enhanced situational awareness when these separation reductions go into effect. “The point is that, based on aircraft and ATC systems and other procedures, the separation standards are being ratcheted down,” the anonymous former regulator said. “So pilots must be aware that they won't have as much airspace to play with as they used to, and if they have to divert, they'll have to be on top of the contingency procedures and in [data link] communication with ATC. The future is not static in terms of separation.
“We're talking about a situation where, based on technology, separation can be reduced,” he continued. “This increases efficiency to manage aircraft, but it means they will be closer together. The future of the North Atlantic is that you're going to need satellite data link systems beyond 2015 in order to fly there. As we get closer to this mandate, everyone is going to have to be thinking about how they will execute the [emergency] contingency maneuver to get separation before making a turn back, if necessary.”
But consider also that while the North Atlantic may represent the busiest oceanic airspace on the planet, only 50% of the traffic flies on the NATS. “On a random routing 1 deg. north of the tracks, these procedures would still apply,” the ex-regulator said. “It may be 'random' but there still could be a lot of other airplanes in the vicinity — you can't assume that you're out there alone. You still need to take the offset from your cleared route if you experience an emergency. You could have an aircraft behind or in front of you — so remember that half of the traffic is off the track system.”
And here's a caveat about which all international operators should be aware: Once the ADS-C component of FANS is mandated, a controller will be watching. “In a non-radar environment,” the former regulator said, “way back when we were just beginning to talk about ADS and CPDLC, pilots would maneuver around weather and not inform ATC, but now with the new monitoring capabilities inherent in ADS technology, there is an automatic ATC alert when an aircraft deviates 5 nm from cleared track. It will make ATC aware of what's going on out there as never before . . . and it will be a revelation to the people on the ground that the airplanes don't always sit on the centerline of the track!” BCA