It was a typical pre-9/11 afternoon as we approached White Plains. New York Tracon handed us off to White Plains Tower and the controllers were issuing their usual rapid-fire instructions to the arriving mass of airline, regional, business and general aviation aircraft.
The frequency was so congested that most of the arriving aircraft were unable to read back the instructions. We had the TCAS turned down to a six-mile range and our heads were on swivels since the airspace was so busy. The TCAS screen was full of targets.
We were watching the business jet ahead of us turn onto final when suddenly it made an abrupt nose-up maneuver. The pilot cried over the frequency, What the…
Our TCAS suddenly showed a target pop up in his immediate vicinity. The pilot then broke over the tower frequency, Tower … did you know youve got a high wing Cessna out here? We almost hit him.
The frequency went silent for a few seconds, and then the tower controller said, Roger, continue. Were not talking to him.
We met that crew in the FBO. The crewmembers were upset and said it had been the closest near mid-air collision of their careers. We dont even know if the other pilot was aware that he had just trespassed through busy Class D airspace.
A review of 500 of the most recent airspace incursion reports to the Aviation Safety Reporting System database shows a variety of causes, but many of them fall into 10 rather clearly defined categories. This analysis, which comes from data posted to the ASRS database before the deluge of flight restrictions after 9/11, shows that unfamiliarity, complexity, confusion and high tech avionics were often to blame.
Airspace incursions run the gamut. They can be mere technical violations of some obscure rule, but they can also have real safety consequences. Statistics on near mid-air collisions show that many of them happen in Class B, C and D airspace, which is perhaps intuitive given that those places are where airplanes tend to cluster.
But the statistics also drive home one point: An airspace intrusion is an indirect measure of increased risk for mid-air collisions. As you get closer to busy airports and into busy airspace, the need to communicate and abide by airspace rules increases exponentially. In addition, keep your head on a swivel even if youre on an IFR flight plan.
A high percentage of the pilots reported being unfamiliar with the airspace boundaries, which makes sense, because unfamiliarity is one of the leading causes of human error. It takes a while to form a mental image of a new patch of airspace, particularly if its complex.
Transient pilots are at a tremendous disadvantage, particularly when controllers use local colloquialisms such as turn right to 180, report the golf course. If youre not familiar, speak up and the controller will translate it to report five miles out.
If youre a transient flying VFR and not using flight following, the odds of error go up tremendously. Picking out local landmarks based on a sectional chart is difficult enough in any airspace. Add traffic-watching duties and the potential for trouble is clear.
As a transient pilot into Santa Monica for the first time, I had a hard time understanding the recommended takeoff procedure, which is complicated because of the urban setting, strict noise abatement procedures, and Class B airspace centered just 5 miles away that surrounded the Class D airspace on three sides.
Controllers in busy metropolitan areas dont have time to baby-sit. If youre unfamiliar, you may be best served by flying into outlying satellite airports rather than main hubs, particularly if youre flying VFR. If you must go into the heart of the beast, expect high traffic flows and rapid-fire communications.
Preparation is the key. Study the charts ahead of time to learn the boundaries, the distinguishing landmarks that can be used to identify the various limits of the airspace and the navigational aids and frequencies that apply. Consider asking local pilots and flight instructors for insight into the normal clearances and potential problems. Some FBOs post the preferred arrival and departure procedures for that airport. By studying those charts ahead of time, you wont get blindsided by an unexpected procedure.
Numerous ASRS reports indicated concerns by pilots that aeronautical charts did not contain key landmarks to help them maintain positional awareness, especially around complex airspace. Having charts with proper scaling to signify key landmarks certainly helps.
In addition, recognize that a airports GPS waypoint uses a different datum than, say, the DME. So if a controller asks you to report five miles out, make sure you know what youre supposed to report fives miles from. Often it doesnt make a practical difference, but sometimes it does.
Complex airspace can make an incursion almost a natural occurrence. Each time I fly into National Airport, I have nightmares of landing and being greeted by the FBI or U.S. Secret Service agents with handcuffs. Worse, you also can be greeted by F-16s if you stray into the wrong airspace.
The airspace in the L.A. Basin is notoriously complex and the radio frequencies are very congested. I believe it is both easier and safer to file IFR for flight operations through the L.A. Basin rather than trying to evade the mish-mash of Class C and Class D airspace that underlies the large Class B.
At least with an IFR clearance there is no question if you are cleared through certain airspace. Note we said easier and safer; we didnt say anything about quicker.
All over the country – especially around Class B airspace but in other places as well – there are spots where adjacent airspace conflicts. Satellite airports are carved out of the inverted Class B wedding cake. Military areas and other restricted or controlled airspace can butt annoyingly close to any airport, even Class B, C or D airports, sometimes extending to the very surface of the runway. This requires you to contact air traffic control before operating out of an uncontrolled airport.
In some locations, ATC has established a frequency where you can obtain a clearance prior to takeoff. If the Airport/Facility Directory doesnt have such a frequency listed, ask the local FBO. Sometimes a sign is located at the end of the runway listing the appropriate frequency. This should be a good hint that getting a clearance is required – or at least strongly suggested.
If your local airport sits very close to a Class B, C or D airport, and if there is a possibility that taking off can result in transgressing into the controlled airspace, the local pilot community can approach the FAA to establish some convenient communication procedures that allow pilots to contact the controlling agency while sitting at the end of the runway and get a clearance.
The next step is to publish the frequencies so everyone will know, including transient pilots. Get the frequencies published in the Airport/Facility Directory and other pilot information aids. Post the frequency on the entrances to the FBO and ramp. Post the frequency on signs at the end of the runway.
High workloads seem to go hand-in-hand with busy airspace. As you near busy airspace, the pace of the controllers voice increases. Even as the instructions and readbacks become ever-more clipped, there is less margin for error because the number of airplanes is increasing.
Devoting more attention to listening to air traffic control in busy airspace increases the pilots workload. At the same time, your heading, altitude and airspeed control must meet a higher standard out of necessity. This increases your workload even more.
In addition, the increase in aircraft traffic means your eyes need to be outside scanning for traffic even more.
As you can see, all of these conditions make busy airspace a huge increase in workload, and it seems even worse if youre coming in from a leisurely en route segment. But while youre paying more attention to aircraft control and communication tasks, dont let navigation tasks become neglected. The problem is that the margin for error within busy airspace is very small.
There are steps you can take to lower your workload, and most of these involve preflight preparation. Besides studying the appropriate charts ahead of time, consider highlighting the appropriate radio frequencies or writing them down so you dont have to fumble for them.
Fold your charts in a methodical manner so that they fold and unfold onto the next sequential section that you will need. Use a kneeboard and have all of these items logically ordered in sequence so that they are immediately available. You will find that taking these fairly small steps ahead of time will do wonders for your workload.
For a quick demonstration of how important the little things are, stash your headset and see how much a cockpit microphone adds to the hassle factor. Cockpit organization is vital. Its very important to have the information you need at your fingertips without having to go searching for it.
Trusting Technology Too Much
Advanced avionics are being installed in general aviation airplanes at a rapid rate, led by moving maps that integrate GPS, terrain and ground-based navaids. The tendency of some pilots is to rely heavily on the advanced equipment, which leaves them stranded if it fails or is programmed incorrectly.
I fly a glass cockpit aircraft for a living, and yes, I like it. But Im always seeking to verify the information it tells me. I definitely back up the navigational information with other sources of data, to include raw navigational data from VORs, DMEs and NDBs, and also with pilotage using an old-fashioned aeronautical chart.
There were a significant number of pilots who reported confusion caused by the navigational equipment and the location of data points that conflicted with other information. Its pretty easy to input the wrong waypoints or longitude and latitude coordinates into the black boxes, so make sure youre following your route by crosschecking your various navigational cues.
Confusion Over Landmarks
Spotting landmarks can be a difficult proposition. In periods of low visibility or during times of summer haze when forward visibility is strained at best, its easy to get confused over where the key landmarks are.
In numerous reports, the pilots lost their position because of the low visibility and wandered inadvertently into someones airspace. Another classic set-up is attempting to navigate at night, especially when trying to avoid the boundaries of a Class B airspace in a large metropolitan area that is unfamiliar to you.
By the way, holiday lighting added to further confusion for night navigation in many ASRS narratives.
Problems Getting Clearances
Dense airspace, by definition, has a lot of communications traffic, so it wasnt surprising to see the large number of reports in which pilots indicated problems getting a clearance to penetrate the airspace. Many of the reports indicated that the pilot attempted to contact ATC on the wrong radio frequency, adding further to the workload due to the confusion and distraction.
A number of pilots reported entering control zones without an ATC clearance when the weather had dropped below that allowed for VFR operations. In each of the reports, the pilots didnt realize the weather had gone below VFR weather minimums in the control zone.
It was inevitable that the NASA ASRS contain numerous reports of pilots misunderstanding clearances. The FARs are very explicit regarding entry into a Class B airspace. You must have specific permission to enter into Class B. You need to hear the magic words, You are cleared into Class B airspace.
Some pilots mistakenly think ATC vectors that lead the airplane into Class B constitute a sufficient clearance. Its an understandable conclusion, even though its incorrect. When you tell flight standards inspectors you were simply following the controllers directions, they arent going to be very sympathetic.
A few of the communication misunderstandings were due to poor sound quality in the aircraft speakers and involved pilots who were not using headsets. Besides protecting your hearing, headsets are vital tools for enhancing the quality of the incoming radio calls.
Hand-held microphones and cockpit speakers make it tough for both the controller and the pilot. Other pilots on the frequency can tell, too. The headsetless pilot sounds like a Weather Channel reporter broadcasting from a hurricane zone.
Finally, if you are ever in doubt about the instruction from air traffic control, have them repeat the message until you clearly understand it.
Cutting It Too Close
Another common problem is often connected with complex airspace. Its something Southern California pilots can understand, and that is running a gantlet of overlapping airspace – such as trying to navigate the Los Angeles complex from north to south. Many of the various airspace entities share common borders, while others allow a fairly narrow corridor for VFR traffic to proceed without a clearance.
In a pilots attempt to get around the airspace, its easy to cut a corner a bit short. More than a few of the ASRS reports indicated terse discussions between air traffic controllers and pilots, with the pilots insisting their map or their navigational equipment showing their position just outside of the airspace boundary while the controllers scope showed the pilot just inside the boundary.
Its far easier and simpler to give yourself a wider margin from the airspace boundary if you can. Youd rather do that than risk an airspace incursion on your pilot certificate and going through the stress of an FAA action.
I didnt realize…
Finally, the last major category of airspace incursions occurred with temporary flight restrictions. Sometimes the TFR hadnt been included in the pilots weather briefing. (Or in the case of the nuclear facility TFRs, incorrect and vague coordinates were posted.) Sometimes the pilot was operating from a nearby airport, didnt feel it was necessary to obtain a weather briefing and wasnt aware that a TFR had been enacted.
Sometimes the location of the TFR is difficult to pinpoint. Sometimes the pilot was on a very long cross-country flight and the designation of the TFR occurred while en route. Its rather interesting to note the number of times that government aircraft rather aggressively intercepted and chased the intruder aircraft out of the TFR area.
Airspace incursions sometimes take on the air of technical violations of arbitrary regulations. However, in the tense days after the Sept. 11 tragedy, inadvertent airspace incursions arent going to be accepted very kindly for the near future. These are tense times and its better to be safe than sorry.
-by Pat Veillette
Pat Veillette is a safety researcher who works in the training department of a large carrier.