Stop, look, and listen

August 1, 1995

Stop, look, and listen. Those words adorn many railroad crossings. The same formula works well in the aviation ground environment. We tend to relax on the ground, but it's worth remembering that one of history's worst accidents happened when both aircraft involved were on the ground. The granddaddy of all runway incursions occurred in Tenerife in the Canary Islands when two heavily loaded Boeing 747s came together on a fog-enshrouded runway. The captain of one of the 747s failed to honor a "hold in position" clearance and started his takeoff before the other 747 was clear of the runway.

The NASA Aviation Safety Reporting System has gathered some impressive statistics on close calls. As in many areas in aviation, there are very few accidents — but when they occur, they can be spectacular. Pilots and instructors should devote more attention to this little-discussed area.

After an average of 220 deviations during each of the last six years, the trend is headed down. Pilot deviations (41 percent) were the leading cause, followed by controller errors (38 percent) and vehicle/pedestrian deviations (21 percent).

In nearly all of the accident cases, weather or darkness played a significant role. Problems are less likely with good visibility in broad daylight when the hazards can be seen. A Boeing 737 flattened a Metroliner that was waiting in the dark for takeoff clearance after being told to "Taxi into position and hold" at Los Angeles. The controller had forgotten the Metro and cleared the Boeing to land. The Metro's strobe lights were not on, and the navigation lights weren't spotted by the Boeing crew until a few seconds before impact.

The most recent accident occurred in November 1994 at night in St. Louis. A Cessna Conquest was cleared onto a parallel general aviation runway but mistakenly taxied onto the active airline runway about 2,000 feet from the approach end. A McDonnell Douglas MD-80 on its takeoff roll struck the Cessna. Again, the lights of the smaller aircraft were not bright enough to alert the MD-80 crew, although at this writing there is some confusion as to whether the lights were actually on.

There are procedures that pilots can follow to avoid the deadly incursion. First, be sure to read back the taxi clearance. Treat it as a regular departure clearance by writing it down.

To help, confusing terminology has been, or is being, eliminated. Terms like the "outer parallel" were sometimes used in clearances at many large airports. A Dallas-Fort Worth taxi clearance several years ago had me wondering what the controller meant when he referred to the "North Bridge." How was I to know that he meant the taxiway that crossed the highway north of the terminal via a bridge? Eminently logical, very confusing, and a bit stressful — particularly with airliners rumbling around the taxiways in large numbers.

"Taxi into position and hold" means pull onto the runway, stop, and be ready to go when the "Cleared for takeoff" clearance is issued. The idea is to move traffic faster; typically, it will save 20 or 30 seconds by putting a departing aircraft into an immediate launch position. At busy places it can mean the difference between getting on your way and waiting another three minutes or longer while another aircraft lands.

"Position and hold" was involved in several of the accidents listed above and should be treated like a live hand grenade. The FAA has recognized this hazard and will no longer issue this clearance after dark.

There are some procedures that you can follow to reduce the position-and-hold risk. Obviously, don't accept it if you haven't completed the entire checklist. Even more obviously, look in both directions before taxiing onto the runway. Be very clear and succinct on your readback of this instruction and try to ensure that your transmission wasn't blocked when reading back the clearance. If there is any doubt, sit it out on the taxiway.

Another technique is to position the aircraft at a 45-degree angle to the takeoff heading so you can at least have some vision over your shoulder looking at the final approach. This may be more psychological comfort than actual assurance, but it won't hurt anything. Finally, if you've been sitting on the runway for more than a minute or so, politely ask if they've forgotten about you. Chances are they haven't, but everybody will be reassured.

There is a new acronym called LAHSO — land and hold short operations. This involves landing and not rolling past a designated intersection, since another aircraft has been cleared to land or take off through that intersection. The objective is to increase airport capacity safely. You do not have to accept the clearance.

To avoid problems after being given a hold-short instruction, remember all the caveats about wake turbulence, know the landing distance your aircraft will need under ambient conditions, and nail the final approach airspeed at the appropriate value. The controllers can provide you with the distance from the end of the runway to the intersection, but you'll probably have to ask for it. Be particularly suspicious if there is any tailwind component or it's raining, snowy, or icy. Abort the approach if things aren't going well. The procedures are on page 2-23 in the 1995 edition of AOPA's Aviation USA, along with a complete list of the airports and runways affected.

Single pilots operate in a much tougher environment than airline crews. Crews are route-checked into each airport before going it alone. There is always one crewmember to steer and one to navigate. Also, an airline flight deck is significantly higher above the ground than the typical light aircraft cockpit; the improved visibility makes it a little easier to maintain orientation.

Don't be hesitant to ask for help or "progressive" instructions for extra guidance. The controllers will be happy to call your turns and direct you step-by-step to the runway or the ramp, as appropriate. Whenever there is the slightest doubt about where you are or where you're going, ask. It is the mark of a professional. An amateur will try to fake it — sometimes with unfortunate results.

Most of the time the controllers can see you from the tower and will be most helpful in keeping you out of the traffic areas. At large airports or those with uneven terrain, however, they may not be able to see certain operational areas. Occasionally the system fails, so keep a sharp eye out and challenge a clearance that seems questionable.

It is as important to know where you are on the ground as it is in the air, and the preceding accidents prove that. We don't yet have $4,000 worth of avionics to guide us when ground bound. It's coming with GPS and moving map displays, but don't expect it in the typical Cherokee in the near future. At major airports, there are some high-tech gadgets appearing or operational, such as surface detection radar and taxiway traffic lights. Even transponder- or GPS-related position reporting equipment is under consideration, but common sense and a good look around will certainly prevent most of the problems in daytime VFR. Night and instrument conditions will require extra caution.

Having the right tools, be it for home repairs or finding your way about a large airport, makes all the difference. For low-tech simplicity, try a taxiway diagram. Both NOS and Jeppesen instrument charts have airport diagrams to show the general layout. Instrument pilots are used to having these diagrams available, but any VFR pilot could consider these charts a good investment, especially if you frequent the larger terminals. You can buy NOS charts in handy booklets, and they are relatively inexpensive. Before taxiing out or while en route inbound, take a moment to familiarize yourself with the ground diagram. It will be one less thing to do while trying to taxi, which is a busy time.

The FAA is experimenting with larger taxi diagrams to make ground navigation a bit less daunting. They could be provided in a separate booklet from instrument approach charts. Not only are the taxiways more clearly identified, but standard taxi routes are being considered. The concept is much like the current standard instrument departure and arrival routes (SIDs and STARs). Rather than a controller's reading each twist and turn along the taxi route to or from the runway, you might be cleared to Runway 23 via "Gray 1." This would be a textual description from the north ramp, for example, outlining each taxiway and any hold short points en route to the runway. It saves communication time, and the pilot would have a hard copy of the clearance in the cockpit. We just need to remember in the single-pilot cockpit that looking outside — not staring at a chart — will prevent the problem.

There has been a major effort to standardize taxiway and runway signs. This is described in detail in the Airman's Information Manual. Good paint markings are also helpful. But at night it can still be confusing with a maze of lights. The problem is the worst at airports where there is little or no grass between taxiways. Everywhere you look there is concrete. New York's La Guardia comes to mind. Taxiway and runway delineation is all done with paint and lights. Add some snow or rain — which absorb much of the paint's reflectivity — and there are bound to be dilemmas.

Problems can also occur at non-towered airports. Be particularly suspicious at airports where there are crossing runways and where a dip or hill will block your view of the opposite end of the runway or an intersection. At a non-towered airport, taxiing into position and holding on an active runway while another aircraft is clearing is an act of faith and not recommended, particularly when there's another aircraft on final.

Review runway and taxiway markings, as well as ground signage, during the biennial flight review. Most pilots devote full attention while airborne, but there is a tendency to relax during taxi. Give your taxi route the attention it deserves. Stop, look, and listen.


See also the index of "Safety Pilot" articles, organized by subject. Bruce Landsberg is executive director of the AOPA Air Safety Foundation.