- The FAA has reduced landing visibility requirements from 2,400 feet to 1,800 feet at more than 500 runways
- At Philadelphia International Airport, reduced visibility requirements added around 85 arrivals per day
- With a reduced visibility procedure at Boston Logan International Airport, the benefit of avoiding flight diversions or cancellations was estimated at $5.7 million per year
Airports referenced in this story
- Improved Approaches and Low-Visibility Operations (IALVO)
- Outlines ways to increase access and flexibility for approach operations through a combination of procedural changes, improved aircraft capabilities and improved precision approach guidance.
The same fog that causes you difficulty on the road in the car poses the same kind of problems for pilots. But a new NextGen procedure is making it possible for pilots to slice through low visibility. Thanks to NextGen, they can land safely when, not too long ago, your flight would have been diverted to another airport.
It's aviation's version of a winning one-two combination: low cost, high impact. The FAA has combined NextGen analysis with equipment that's already in place on aircraft and on the ground to dramatically increase capacity and access to airports during periods of low visibility.
The FAA has added a NextGen procedure to the conventional ground-based navigation equipment in place at many airports. These Instrument Landing Systems (ILS) guide aircraft on their approach to the runway for landing during periods of low visibility; the new procedure enables equipped aircraft to land with even less visibility than before. At Detroit Metropolitan Wayne County Airport, for example, equipped aircraft can now begin the approach and land when the airport reports visibility of at least 1,800 feet, where before they had to be diverted if the visibility was less than 2,400 feet.
The capability is being used at major airports, including New York-area LaGuardia International and Newark Liberty International. On a day when a half dozen aircraft can land that might have otherwise been turned away, it's a big deal for the airlines and the airport.
"All you need is one aircraft to land and the benefits begin," said Warren Strickland, the FAA's New York Area Program Integration Officer. "With connections, the benefits are exponential."
The FAA has significantly lowered the visibility requirements for more than 500 existing ILS approaches. To take advantage of these lower visibility procedures, aircraft have to be equipped with either autopilot, computer-directed navigation or a head-up display (a transparent readout of flight data in the pilot's line of sight on the aircraft's front windshield). Most commercial aircraft flying today have at least one of those pieces of equipment.
In addition to improving the access to individual airports, there's an overall benefit to the entire national airspace system. Philadelphia International Airport was notorious for having to shut down during low visibility. So, not only were there delays at Philadelphia, but it affected the entire East Coast as flights were diverted to other airports and delays rippled across the country. When Philadelphia had its approach minimum lowered to 1,800 feet on one of its runways, the arrival rate increased from 32 flights per hour up to 38 during periods of low visibility. This added around 85 additional arrivals per day, many of which were large aircraft coming from international destinations.
Even though the need to land in low visibility only occurs in a small percentage of daily flights, the ability to avoid diversions and cancellations is prized. When a lower-visibility procedure was published at Boston Logan International Airport, the benefit of avoiding flight diversions or cancellations was estimated at $5.7 million per year.