I have been led to believe that it is OK to use the entire available runway to takeoff but, for some reason, it is not OK to use the same space for landing – you must be passed the threshold. Today I was landing at Bakersfield CA (KBFL I think) and it seemed that at least half of the runway was unavailable for legal landing (if my info is correct) see pic:
So my question is: Why are things this way?
Noise reduction/pollution, protecting a taxiway that traverses it, or obstacles at that end of the runway. I’m sure there are others, and it probably varies from airport to airport.
good answers… I hadn’t thought of any of that 
That’s an interesting airport. It not only has a displaced threshold (the area with the white arrows), it has an EMAS (the area with yellow chevrons). I’ll find and put the information about EMAS below. So in this case I’d think the displaced threshold also offers a buffer so that airliners in particular do not touch down on the EMAS material area.
Regards
“Engineered Materials Arresting Systems (EMAS)** . EMAS, which is constructed of high energy-absorbing materials of selected strength, is located in the safety area beyond the end of the runway. EMAS will be marked with yellow chevrons. EMAS is designed to crush under the weight of commercial aircraft and will exert deceleration forces on the landing gear. These systems do not affect the normal landing and takeoff of airplanes. More information concerning EMAS is in AC 150/5220-22, Engineered Materials Arresting Systems (EMAS) for Aircraft Overruns.” From FAA AIM section 3.
I’m not sure that the entire blast overrun is EMAS, it doesn’t make sense that the entire length would be a expensive material. Reading the charts and comments on the airnav.com page lead me to believe that the extended blast pad is for noise reduction (aircraft cannot use blast pad for takeoff) with the area East of the field being noise sensitive. Yellow chevrons are use for blast overruns as well as EMAS. They mean “keep off.”
Excellent point.
While Blast pads are often made from EMAS (for landings in the opposite direction), it does seem excessive that the whole length for that extended area would also be an EMAS area especially with the extended displaced threshold.
Regards
It often also helps to read up a little on the history of a particular airport.
In Bakersfield the airport use has changed dramatically over the years. And the runway length once needed for heavy aircraft to land and take off is now no longer required.
At the same time people keep on buying and building houses right next to existing airports, and then complain about airplane noise. One way to reduce these nuisance complaints is, where possible to change the way airplanes land and takeoff from a particular runway.
The displaced thresholds marked by white arrows allow you to takeoff, meaning at the departure end of that runway you are likely already higher than if you were to start your roll from the regular threshold.
And it keeps you higher longer, when approaching from that end, because you are not allowed to land in that section.
Many airports on the west coast were built during WW2 and used for training, final aircraft testing and of course the possible attack from the west. And often they were later turned into municipal or ANG airports.
As uses changed the airports also changed.
Thank ya’ll very much for the discussion. So I guess if I see the yellow Chevrons then I should treat that as a non driveable surface. I really never thought about any of these things – mutating airport purposes, trying to satisfy the needs of growing cities/neighbors… it is fascinating.
I’ll have to double check in the FAR, but I am 98% sure you can only use displaced threshold for takeoff the white arrows, not the yellow. You wouldnt be allowed to use the yellow triangles for takeoff.
You’re correct: the pavement marked with yellow chevrons is not available for aircraft movement. That area is commonly referred to as the “overrun” or the “blast pad.” In the case of KBFL, that pavement was originally part of Runway 30R, but at some time between 1956 and 1968, it was converted to overrun.
Overruns serve three purposes: they provide a solid surface for aircraft that inadvertently overrun the runway during landings and rejected takeoffs, provide an obstacle-free “clearway” for aircraft taking off, and provide a solid area behind aircraft taking off that prevents erosion from jet blast. They may also include EMAS (Engineered Materials Arresting System).
Basically, some regulations require aircraft to cross the departure end of the runway at an altitude no lower than 35 feet above the ground during takeoff. If that same runway has a suitable clearway, then half of the distance to reach 35 feet can include the clearway, meaning the airplane is only required to cross the threshold at 17.5 feet above the ground. This could allow aircraft departing Runway 12L to carry greater payloads.
The displaced threshold–marked by the white arrows along the runway centerline–is something completely different. This area is available only for takeoff in both directions. You’ll usually see a displaced threshold when there are significant obstructions approaching the runway. Like takeoff, there are required clearances in the area approaching the runway for landing. If an immovable obstruction penetrates the required approach path, then the path must be relocated to accommodate the obstruction. Here’s a quick drawing I made that shows what’s happening…
In the top drawing, we see the runway with two declared distances: the Takeoff Runway Available (TORA) and the Landing Distance Available (LDA). The dashed yellow line shows the sloped “surface” that must be clear of obstructions. The massive red obstruction penetrates that approach surface. So…
The second drawing shows the fix. By sliding the approach surface further down the runway, we provide the required clearance over the obstruction. The approximate place where the surface meets the runway becomes the displaced threshold.
Here’s the declared distances for KBFL from the Airport/Facilities Directory…
The TORA for Runway 30R is 10,848 feet, while the LDA is 7,429 feet. In this case, for some reason, the landing threshold is displaced 3,419 feet down the runway. While this is normally done to accommodate obstructions, it’s also possible the threshold was displaced to accommodate the surrounding community and was placed at that location simply because that’s where Taxiway B meets the runway.
Other airports with significant displaced thresholds are San Diego (there’s a massive hill approaching Runway 27) and Chicago-Midway (obstructions everywhere). Many airports have overruns. Those at places like Burbank and Midway include EMAS.
You can read more about declared distances in Wikipedia’s “Runway” article. It’s actually well written!
I hope this helps. Fly safe!
I really really despise those kinds of people. Buying or building a house is not something you do on a whim. It’s one thing to live somewhere and then have an airport built next to you, but if you deliberately buy a house right next to an existing airport runway (motorway, church tower, steel plant, garbage dump, brewery, outdoor restaurant, etc.) it’s your own fault and you have to live with it … 
if you guys think we have it bad, did you see the Laguna Seca race track might get shut down because rich people moved in next door?
The best thing was when we were at the home of one of the CFIs at my airport, I think to celebrate her kids birthday. She and her husband had moved to a relatively new neighborhood because it was close to KCNO. There were about 20 people there, about 2/3 either active pilots or retired pilots.
Then some clowns from the homeowners association rang the bell to sign her up for a complaint against Chino airport and the Planes of Fame warbird shows on Saturday in particular 
That went over really well. They really regretted not looking at little closer at all the cars in the driveway.
YGTBSM. Hopefully that lawsuit won’t progress very far! I love the fact that the coalition suing to close the track has routinely used water usage as a primary reason to stop development near their golf course…which probably uses an enormous amount of water itself!
Denver’s “new” airport was located in the middle of nowhere specifically to avoid noise issues. Now developers are dropping houses right on the airport’s perimeter, and the new residents are complaining about noise! Runway 25 is not normally used now after about 10 p.m. to reduce the noise impact on surrounding neighborhoods
Runway 30 at BFL used to end right at the intersection of Norris and what’s now Airport Road. The airport was built prior to WWII, but used by the Army and expanded during the war. You can see vestiges of the old cross runways on the southeast corner of the airport, which was typical of airport design prior to jet aircraft.
In the 60’s, the cross runways were closed, a parallel runway was built for GA, and the main runway, which became 30R/12L was basically shifted to the northwest by about 2,500’. This was likely for several reasons, but my guess is noise abatement for Oildale, as well as to accommodate the installation of an ILS and approach light system, which closed that old SE 2500’ and turned it into a stopway with the approach lights installed. Two more reasons you might displace a threshold are to provide an obstruction-free zone for an instrument approach, as well as to protect an ILS critical zone.
Over the next 20 years they tacked another 1000’ onto the NW end of the runway. Then in 1987, to be able to open up to larger jets, they displaced the threshold of 30R another 3300+ feet, keeping the old stopway, but moving and embedding the approach lights into the new displaced threshold. They also extended the runway 4100’ to NW. So now you had all that new runway, plus the displaced threshold available for takeoff either direction.
In 2013, they found substantial cracks in the runway, so they underwent a four-year rehabilitation from 2015-2019. During that project, they removed the old 2,400’ of abandoned stopway to the southeast (so it really shouldn’t still be in the sim - that’s a candidate for a world hub edit. Anyway, construction is yet another reason you might have a displaced threshold - during temporary construction of the same or an adjacent/crossing runway. Sometimes you can get a “relocated” threshold that changes from day to night, to accommodate nighttime construction.
Interestingly, there is an airport layout floating around out there from the time of the 2015 project that shows an “ultimate” relocation of the displaced threshold about 1600’ to the southeast. If you look closely at an aerial, there is glideslope equipment infrastructure where the 1000’ markers would be in that scenario. I wonder if that plan is still in the works.
Yeah, when Burbank instituted the new SLAPP and OROSZ RNAV DPs a few years ago, it started taking aircraft to the SW, over Sherman Oaks (which really hadn’t been the case prior as the old ELMOO DP goes to the SE). They went from a couple hundred noise complaints a year to over 600,000.
That’s disgusting 
Laguna Seca is probably the most famous American race track (ovals don’t count, I’m from Europe 
) That’s like closing Monza, Brands Hatch or the Nürburgring.
In a town near me the boss of one of the largest dairy companies of the country had the Whiskey VFR landing approach of a controlled airport (which already ran over a motorway for noise reasons) simply done away with, because it was too close to his villa …
They used to run road races in the town of Carmel until someone hit a tree and died. So they bought a little section of Fort Ord to make Laguna Seca. Fort Ord closed in the 90’s, and is now a mostly undeveloped National Monument. That said, someone built a golf course and housing development adjacent to the racetrack in 2000 and I’m surprised it’s taken them this long to NIMBY it.
I always iterate on my streams that large parcels like airports, stadiums, malls, and racetracks are merely placeholders for real-estate developers. When the market is as high as it is, there always seems to be more NIMBYism than usual, obviously some due to actual noise and pollution complaints, but you can’t help but think about the target on that big, undeveloped parcel. And LS is the only piece of land for several miles north, west, and east, that isn’t federal land.
See also El Toro MCAS for past, Reid-Hillview (KRHV) and Rocky Mountain Metro (KBJC) airports, presently.
