“Fly the airplane until it’s parked,” was the-oft-repeated command I heard from my flight instructor when learning to fly and working towards obtaining my private pilot’s license. There are many things to consider during flight, including weather conditions, aircraft speed, wind direction, and communications. But, situational awareness is also vitally important. It means not only having an accurate understanding of what's happening around you and what is likely to happen in the near future, but knowing exactly where you are and where you're heading. My flight instructor’s favorite saying in this regard was “You can't fly along fat, dumb and happy.” He was telling me to think ahead, anticipate what’s next and plan for it as opposed to reacting to it. Sage advice indeed. It holds true regardless of whether one’s flying a Cessna 172 Skyhawk or a Boeing B777-300ER and is particularly relevant when taxiing at a large, complex airfield. So, just how do pilots navigate their way around big airports like Chicago O’Hare or London Heathrow?
Flight crews operating commercial aircraft often benefit from using advanced in-cockpit technology. This includes panel mounted, moving map displays that allow them to follow their aircraft movement on the airport diagram page. The benefit is exponential when operating at night or in low-visibility conditions. Those aircraft which don’t have electronic displays require the crew to have tablet computers with similar taxi diagrams or even paper charts, which are what we depended upon when learning to fly. (Those charts are produced by Jeppesen, an American company offering navigational information, operations planning tools, flight planning products and software. Jeppesen's aeronautical navigation charts are often called "Jepp charts" or simply "Jepps" by pilots, due to the charts' popularity.) Regardless of what equipment is used, cockpit communication is key since the pilot taxiing the aircraft will follow guidance from the other pilot who is constantly referring to the airport diagram and communicating with air traffic control (ATC). Situational awareness is critical to avoid incursions and park at the proper stand.
Construction Notice Diagrams are also beneficial to pilots since many larger airports are constantly undergoing expansion, revamping or construction. Studying these diagrams assist crews in determining any potential limitations to their taxi routes during the flight planning process. We should bear in mind there will be any number of construction projects at US airports in the near and longer term as a result of the US Infrastructure Investment and Jobs Act. This legislation authorized $5 billion for improved air traffic facilities and $15 billion for aviation infrastructure.
In-cockpit communication is crucial and following ATC instructions is vital to successful flight. Hold short instructions must be read back every time they're issued. These can pertain to holding short of a taxiway or a runway environment for safety reasons. Land and Hold Short Operations (LAHSO) are used at many airports with intersecting runways. Pilots are asked to confirm a hold-short instruction even before they land on a runway that intersects another one further down the landing surface. If a crew cannot accept such an instruction, they must advise ATC, which would then coordinate traffic on the other runway. LAHSO clearances are not mandatory, but if accepted and once on the ground, all hold short instructions must be followed. This applies to both inbound and outbound traffic. Many complex airports have signage and specific taxiways for arriving aircraft and another set of the same for departures. These come in handy, but certainly can add to the likelihood of confusion in the cockpit so listening and repeating the ground controller's instructions are essential.
It’s also possible that experienced airline captains might request progressive taxi instructions if they’re not familiar with the airport, especially during inclement weather or at night. When requested, a progressive tax instruction is used upon clearing the landing runway. ATC can provide a complete set of turns and routes at that point before the start of the taxi. These step-by-step instructions are given in stages during the aircraft’s taxi. Progressive taxiing is provided not only when requested by the pilot, but also when deemed necessary by the controller due to traffic or field conditions such as construction work or closed taxiways.
Ground controllers can use their equipment to aid pilots when giving taxi instructions. The Airport Surface Detection Equipment Model X (ASDE-X) is a surveillance system using radar and satellite technology that allows air traffic controllers to seamlessly track the surface movement of aircraft and vehicles. The system uses a combination of surface movement radar and transponder multi-lateration sensors to display aircraft position labeled with flight call-signs on an ATC tower display. The integration of these sensors provides data with an accuracy, update rate and reliability suitable for improving airport safety in all weather conditions. Thirty-five major airports in the United States have received such ASDE-X Systems. These systems also features advanced conflict detection and alerting technology, which uses complex algorithms to alert controllers of potential aircraft and/or vehicle incursions. Further, the system was designed to support Automatic Dependent Surveillance - Broadcast (ADS-B) in which an aircraft determines its position via satellite navigation or other sensors and periodically broadcasts it, enabling it to be tracked.
To add to the potential for problems, air crews must listen for and comply with ground control directives issued over a frequently congested radio frequency. So, regardless of the equipment used by pilots or controllers, the best way to prevent a runway incursion or accident is to utter the two magic words “Say Again.” This will ensure the transmitting party knows the receiver has not fully understood the message. Opening the door for a clear repeat of the intended message will go a long way towards making sure flight crews safely navigate complex airport ground environments.
Thank goodness for the advanced technology available to today's aviators, ensuring a safer environment both in the air and on the ground.
Until next time...safe travels.