Tag Archives: Runway Safety

New Runway Takeoff & Landing Performance Assessment Starts October 1

matrixWhen the weather is not sunny, dry, and clear, pilots preparing to takeoff or land need to know what condition the runway is in. To improve these reports, the FAA and aviation community have developed new standards to improve safety during inclement weather. Airports will begin using the new Takeoff and Landing Performance Assessment (TALPA) standards on October 1, 2016.

The new standards communicate runway conditions in terms directly related to their affect on aircraft performance. Airport operators will employ the Runway Condition Assessment Matrix (RCAM) to report runway conditions. The matrix is a standardized format that is based on aircraft performance data supplied by the airframe manufacturers for the type and depth of each runway contaminant.

The new standards replace subjective judgments of runway conditions that are now reported with a Mu number that describes a coefficient of braking friction. Using the FAA example of this system, a runway covered with 2 inches of dry snow would be reported as: “FICON 2IN DRY SN OBSERVED AT 1601010139. 1601010151-1601020145” along with Mu values as “TAP MU 29/27/29 OBSERVED AT 1601010139. 1601010151-1601020145.

Starting October 1, these conditions would be reported this way: DEN RWY 17R FICON (5/5/3) 25 PRCT 1/8 IN DRY SN, 25 PRCT 1/8 IN DRY SN, 50 PRCT 2 IN DRY SN OBSERVED AT 1601010139. 1601010151-1601020145. With this information, pilots would then consult the aircraft flight manual to determine what performance they can expect from their airplane. Note that the numerical Runway Condition Codes, based on the RCAM, subdivide the runway into three segments when the contaminants vary.

Airport operators will assess the runway surfaces, report the contaminants, and use the RCAM to determine the Runway Condition Code. The same code can cover the entire runway when there is no variation in the contaminant. These codes will replace Mu numbers, which the NOTAM system will no longer use.

This does not mean pilots should stop reporting braking action. They will still be used and shared. However, the terminology used in these reports will change on October 1. “Medium” will replace the “Fair” braking action assessment. And airports will no longer be able to report a “NIL” braking action condition. Under the new system, NIL conditions require airports to close that surface until they are satisfied that the NIL braking conditions no longer exist.

Chicago Exec urges aircraft operators to review the appropriate performance sections of the aircraft flight manuals for their airplanes and develop procedures that will enable them to take full advantage of the new runway condition reports. For more information, see Safety Alert for Operators (SAFO) 16009.

Airport 101: Pavement Markings Keep Pilots in Line

PWK-59Chicago Executive Airport is one of thousands of airports that dot the American landscape. Each of them is different, but pilots have little trouble navigating around them because each of them use standardized pavement markings on the taxiways and runways that safely and efficiently guide them from the ramp to the sky. (Although they didn’t offer much help to the runners who raced about the airport several years ago, but they did get to see them at close range.)

Runway markings are white, and the elements employed depend on the type of approach pilots make to it. Runways with visual approaches, where the pilot eyeballs his arrival, has the fewest markings, the runway number, which is its magnetic heading to the nearest 10 degrees, and a centerline. These are on all runways. If the strip is 4,000 feet or longer or used by jets, it will have a visual aiming point, two broad white stripes on either side of the centerline approximately 1,000 feet from the threshold.

If it is intended for commercial use, markings (either a series of longitudinal or one lateral stripe) identify the pavement suitable for landing. A number of airports, like Chicago Exec, have displaced thresholds, usually to ensure an airplane’s safe approach to touchdown. Arrows on the pavement point to where the legal landing area begins.

All runways served by a nonprecision instrument approach, which in bad weather provides horizontal guidance to the runway, have these four markings. Chicago Exec has precision instrument approaches leading to both ends of Runway 16, which also provides vertical guidance to the pavement, which is why it has a touchdown zone. The rectangular bars are arranged in symmetrical pairs spaced 500 feet apart. As the number of bars decreases, so does the length of the remaining runway. Precision runways also have side stripes.

PWK-34All taxiway markings are yellow, and a centerline and markings denoting holding positions are common to all of them. A continuous strip 6 to 12 inches wide, the centerline does not guarantee wingtip clearance with other aircraft or obstacles. A line indicating the edge of the taxiway is applied when it does not correspond to the end of pavement.

Chicago Exec has an enhanced centerline, yellow dashes that parallel the continuous centerline, which tells pilots they are approaching a runway holding position and should be slowing down and preparing to stop, or hold short of the runway or intersections. Hold-short markings have two solid stripes on one side and two dashed lines on the other. Airplanes must stop when approaching the solid lines, which are on the taxiway side of a runway intersection. They may continue without stopping when on the dashed-line side, which they face when exiting the runway after landing.

Solid white lines on either side of a dashed centerline denote the edges of vehicle roadways that cross pavement also intended for aircraft. Some airports also use “zipper” markings, alternating white blocks. In either case, aircraft have the right of way. A thick white block on the pavement denotes where vehicles must stop at intersecting roadways or before crossing taxiways or other operational areas.

Working in concert with an airport’s pavement markings are a variety of signs of different colors that tell pilots where they are on the airport, and which way they should turn to reach their desired destination whether it is the departure end of a runway or a parking area. We’ll introduce them in our next Airport 101.

EMAS: Good as New

EMAS Falcon

The early morning hours of January 26, 2016

Airports are labor intensive businesses. Every time you turn around, there always seems to something that needs attention.

A runway check each morning is easy enough to point out a broken runway light or two, or patch a piece of crumbling taxiway pavement. Sometimes though, the work’s a bit more involved, like when an airplane ends up somewhere we hope it wouldn’t, like a few months ago when a Falcon 20 landing on runway 16 ran through the engineered materials arresting system (EMAS) at the south end of the airport. The crushable blocks of this new-age runway safety system, did their job and halted the airplane with minimum damage to the airplane and zero damage to the pilots.

The EMAS engagement did leave a pretty glaring hole in the block structure though, something the airport fixed last week with the help of Boland Construction out of New York, a company experienced at EMAS repairs. The work was planned for eight nights of runway closures from 10 pm until 6 am the next morning. But time is money and airports and the businesses that depend upon us don’t make much when the main runway is shut down. The basic plan was to complete as much work each night safely and hope to maybe shave a night off the calendar which would mean less disruption for users.

L 3-20-16 digital file1 202

Today, the end of the runway’s all spic and span. Photo courtesy Lee Hogan

On Monday evening, the first barricades went up to protect workers and warn pilots again the runway should not be used. Boland’s nine employees removed a number of extra EMAS blocks that looked questionable on second inspection and used torches to loosen the adhesive that originally held the blocks in place. Time to call it a night.

Tuesday’s efforts were rained out, but everyone was back on Wednesday at 10 pm when the new blocks were put in place. By Thursday night, there wasn’t much to do except caulk the blocks – just like your bathroom tile – and add the new yellow striping. By Friday morning, it was time to coordinate with the control tower to keep aircraft away and allow everything time to cure. By Saturday morning, the long runway was open for business.

In the end, the teams managed to shave three full nights of work from the project which translated into increased runway availability for airport tenants and transient operators and it was back to business as usual.

Along with the runway, the 16 instrument landing system (ILS) was also brought back to life without the need for another flight check. Thanks for your patience everyone.

 

Airport 101: A Runway is More than an On & Off Ramp for the Sky

Palwaukee_Municipal_Airport_(USGS)A runway is what makes a defined area an airport. As the FAA’s exhaustive airport design and engineering standards suggest, it is more than a long, straight strip of dirt, gravel, grass, concrete, or, on two of Chicago Executive Airport’s three runways, asphalt cut with shallow grooves to help dissipate water so the wheels of landing aircraft will not hydroplane. The third is paved with ungrooved asphalt. This asphalt is but the top layer of several applied on top of a substrate graded to a precise longitudinal crown that ensures water will run to its shoulders.

Chicago Exec’s runways are identified by the magnetic headings to the nearest 10 degrees. The three-digit compass headings for each end of PWK’s primary Runway 16/34 are 161° and 341° to 16 and 34. Painted markings not only “name” each end of the runway, they identify the centerline, threshold, touch-down zone, which is right after the runway number, and the fixed distance marks, a diminishing number of longitudinal lines spaced 500 feet apart.

Surrounding the pavement is a runway safety area, a smooth graded area free of obstacles that would damage an airplane that inadvertently undershoots the threshold, over-runs the opposite end, or veers off the pavement to either side. The runway lights that parallel each edge are frangible, designed to break away from their mounts when hit. Because an airplane’s speed plays a significant part in undershooting the runway threshold or over-running its other end, the FAA requires runway safety areas to extend 1,000 feet beyond the pavement. When this space isn’t available, airports, like Chicago Exec, employ EMAS, engineered material arresting system. As recently demonstrated, EMAS reliably absorbs high amounts of kinetic energy without excessive damage to the aircraft.

Chicago Exec’s Runway 16/34 is 5,001 feet long and 150 feet wide. Runway 12/30 is 4,415 feet long and 75 feet wide, and Runway 6/24 is 3,677 feet by 50 feet, but their entire lengths are not available for landing. The threshold of Runway 12 is displaced 295 feet from the actual end of the pavement. Runway 30’s threshold is displaced 432 feet. Runway 6/24’s thresholds are displaced 372 feet and 1,249 feet respectively. Airports displace their thresholds for a number of reasons, from obstacle clearance and noise abatement or meeting the undershoot and over-run runway safety area requirements.

R30White arrows, like the ones here on Runway 30, designate the displaced threshold. Airplanes can taxi on and start their takeoff runs from a displaced threshold, but they cannot land on them. This reduces the runway’s available landing distance. Displaced thresholds do not shorten Chicago Exec’s Runway 16/34, so its entire 5,001 feet is available for landings.

Available landing distance isn’t the only number important to jets; the accelerate-stop distance is another. It’s the distance a jet needs to reach V1, and then stop using maximum braking, if an engine fails before or at this airplane-specific speed. If an engine fails after V1, there isn’t enough pavement to stop safely so the pilot continues the takeoff on one engine, which is a design requirement for commercial and corporate jets. In planning every flight, pilots look at their destination’s runway information to make sure the runway meets the airplane’s requirements.

A runway’s requirements can also extend off an airport’s property. At most airports, a 3-degree glideslope ensures that a landing airplane will have an obstacle-free approach slope between its final approach fix and the runway’s touchdown zone. Several different light systems help pilots fly this approach path in good weather. Addison uses a PAPI, a precision approach path indicator composed of four lights that shine red or white depending on the airplane’s elevation. Four red is too low, four white is too high, and two of each is just right.

When the weather is bad, pilots follow their instrument landing system instruments, which align them with the runway centerline and keep them on glide path. Each instrument approach has weather minimums classified by ceiling and visibility. With its ILS, Runway 16 minimums are 300 feet and a mile, which is why it’s served by an approach lighting system, a combination of light bars and strobes that help pilots quickly make the transition from instruments to the runway and a safe landing.

Runway 34 EMAS Enhances Safety at Chicago Executive Airport

Chicago Executive Airport’s main runway, 16/34, is 150 feet wide and 5,001 feet long. Constrained by Hintz Road to the north and West Palatine Road to the south, it will not grow any longer. But it will soon be safer, when the installation of the engineered material arresting system (EMAS) is completed at the departure end of Runway 34. If you’ve driven Hintz Road lately, you’ve seen the work on the other side of the airport fence.

Runway 16/34 safely serves the aircraft that call Chicago Exec home, but when the weather is bad, or there’s a rare problem with an airplane, safety is enhanced by an overrun area at each end of the runway. The FAA calls them a runway safety area, and it recommends 1,000 feet. In cases where that isn’t possible because the necessary real estate isn’t available, the FAA offers federal Airport Improvement Program grants to fund the installation of EMAS, which quickly and safely stops an airplane in much shorter distances with little or no damage to the airframe.

To date, EMAS is installed at more than 100 runways at 60 airports worldwide. Chicago Exec is one of the rare general aviation airports that not only have EMAS—the system is generally found at airports that serve commercial operations—it will have EMAS at both ends of its main runway. The airport completed the EMAS at the departure end of Runway 16 around this time last year, said Jamie Abbott, airport director. And before this year ends, the bookend system will be complete on the departure end of Runway 34.

As of this week, the contractor has finished the 170-foot wide, 231-foot long foundation that will connect the EMAS blocks to the runway’s threshold. The EMAS at the other end of the runway is of equal width, but it is 243 feet long. In the coming weeks, workers will begin placing the EMAS blocks. From Hintz Road they may look like large, heavy concrete cubes, but the arresting secret of their contribution to safety is hidden within. Continue reading