Ask the Captain: How safe are airports with short runways?
John Cox is a retired airline captain with US Airways and runs his own aviation safety consulting company called Safety Operating Systems. Here he answers Paste BN readers' questions.
Question: How safe are commercial airports with short runways?
– Charles P., Chicago
Answer: Commercial airports certified by the Federal Aviation Administration's 14 CFR Part 139 are very safe. Runway length is carefully calculated before every takeoff and landing with good safety margins. Pilots know that the runway length is short, so they pay special attention to touchdown points and approach speeds.
Q: When taxiing onto the runway and preparing for takeoff, I've noticed some pilots very deliberately perform a slow 90-degree turn and immediately stop when lined up for takeoff so as to maximize every foot of runway in front of the aircraft. In other instances, the pilots take a gradual turn and may coast for 20 feet before applying thrust. Is there a reason, or is it pilot preference as to how they enter the runway and proceed with takeoff?
– Eric, Mentor, Ohio
A: Some of it is pilot preference, but there are also other considerations. Being precisely aligned with the center line is necessary because the airplane accelerates quickly; if you are not aligned, significant control input is necessary, which can be uncomfortable for the passengers.
It is probable that the cases where the airplane stops on the runway are due to takeoff clearance from air traffic control not being received. Once that clearance is received, the pilots release the brakes and advance the thrust levers.
On shorter runways it is normal to make a 90-degree turn to have every foot of runway available should it be necessary to reject the takeoff.
Q: One can see the wheels go up after takeoff but not the flaps. What is the procedure for the flaps during takeoff?
– Ivan, Pensacola, Florida
A: The flaps (and slats, if the airplane is equipped with them) remain down until flap retraction speed is reached. Flaps produce lift at low speed; consequently pilots do not retract them until the speed is high enough to have the proper amount of lift.