Ask the Captain: Why can I hear the flight attendant's PA fine but not the pilot's?

On the runways of every airport there are black marks where the tires of the landing gear touch down. Over a period of time does the rubber build up to the point that it becomes unsafe and has to be removed?

– James B., Daniel Island, South Carolina 

Yes, the buildup of rubber deposits can adversely affect the braking on a runway when it is wet. 

A typical airliner will deposit approximately a pound of rubber per tire during a landing. High-use runways build up tire deposits frequently. 

Most airports have a runway maintenance plan that includes cleaning the deposits. This cleaning is often done at night when the demand is lower. There are a variety of ways to clean the runway, including high pressure water, solvents or a combination. 

Why is the quality of the captain's public-address system so bad compared to the ones that the flight attendants use? I often can hardly hear the captain's in-flight announcement once the plane is in the air.

– Ray W, Tucson, Arizona

It varies dramatically from airplane to airplane.  One consideration is that the pilots can only barely hear their PAs, while the flight attendants hear theirs clearly. As a result, if something is wrong with a flight attendant's PA, it will be reported to maintenance, whereas the pilots may even not be aware theirs is garbled. So if you notice that is the case, mention it to them as you pass the cockpit on your way out.

John Cox is a retired airline captain with US Airways and runs his own aviation safety consulting company, Safety Operating Systems.