Ask Captain Lim

Greetings,

I mistakenly stumbled across this site and I am floored!!!! I love aviation and I had no idea that this site was here. I love it!

Here is my question. Am I to believe that a US$20.00 CD player can actually bring down a $270 million dollar aircraft?

I fly all the time so I know the rules. Still I love to listen to my music when in the take-off roll, climb-out and passing the clouds to cruising altitude. I know I should turn it off but most of the time, the Flight Attendant do not have time to check each passenger.

Just how serious is keeping a walkman or CD player on during that climb out?

Thanks.

Calvin Walker,
Ph.D.

Hi Calvin,

You have asked an interesting question and it would benefit others to read this as well. I have encountered many such incidents where passengers have ignored repeated requests to stop using any passenger electronic devices, especially cellular phones. Walkman or CD player users - are less in my encounters. How serious are they to the safety of airplanes? They have caused airplanes to do an uncommanded turns in an approach, caused the navigation systems to go haywire, fuel quantity to read zero, causing confusion to the computers, so on and so forth.

Many pilots have reported interferences to communication and navigation equipment in various stages of their flights. How they knew these interferences came from passengers? When a pilot detects an unusual electronic fault, he would be notified by the inbuilt warning systems. If he could not troubleshoot the faults in the normal manner, his next action would be to find out from the Flight Attendants to see if any passengers were using some prohibited electronic devices. Sure enough, when one such device was found and requested to be switched off, the navigation system would return to normal.

Last year, as a Boeing 737 was making an approach to Chicago Midway Airport, the pilots noticed an erroneous airplane position from the cockpit instruments. At one point, it was indicating that it was on course and the next moment it was off course, showing that it was too far South. When they finally sighted the Runway, they were too high and too far North to land. They eventually discovered that a lady passenger was using her cell phone. When she was asked to turn it off, the instruments returned to normal and the Boeing 737 landed safely.

Of course, this incident did not suggest a crisis was at hand. Electronic interference alone might not be a major threat but combined with other factors like bad weather and pilot's fatigue, these minor threats could contribute to accidents.

Let me digress a little bit on cell phones. Some people are a little skeptical about in-flight ban on all phone use, suggesting that the Airlines were trying to force passengers to use the expensive satellite phones on board the airplanes. In fact, this prohibition is a Federal Communication Rule.

Now, your walkman and CD player are classified as non-intentional transmitters of radio signals. Its usage is not as critical as a cell phone that intentionally transmits radio signals. The RCTA (Radio Technical Commission for Aeronautics) Special Committee recommends that any passenger electronic device which intentionally transmits radio signals, i.e. cell phones, should be prohibited for use by passengers at all times while on board airplanes except after they have been parked at the gate. So, your Walkman and CD player, being a non-intentional emitters are allowed to be used in cruise apart from during taxi, take off, climb out, descent, final approach and landing unless the Airline has determined that the devices cannot be operated.

So, in the worst scenario, a US$20.00 CD player could bring down a very expensive airplane!

Happy flying always, of course with your walkman and CD player (only during the cruise, okay?)