Sport Pilot Talk

SSDriver · Joined: 15 Apr 2011 Posts: 31 Location: NJ

One of my study test questions:

If the aircraft’s radio fails, what is the recommended procedure when landing at a controlled airport?

a) Enter a crosswind leg and rock the wings.

b) Observe the traffic flow, enter the pattern, and look for a light signal from the tower.

c) Flash the landing lights and cycle the landing gear while circling the airport.

Answer is B, given those options.

My question was.. Even though B would be correct procedure.. Would you or would you not want to Squawk 7600 in addition to "B".

My line of thinking was this would be an additional layer to assure the controller that your not just being rude/knuckehead, jumping into the pattern. Or am I wrong in correct scenario would be for using 7600?

drseti · Joined: 28 Nov 2009 Posts: 1390 Location: Lock Haven PA

SSDriver wrote: Would you or would you not want to Squawk 7600

Drew, not all Class D (towered vs. non-towered -- I don't like the terms "controlled" and "uncontrolled"; that implies chaos at the latter) airports have radar or the ability to monitor transponder signals. In fact, the majority of towered fields do not. So, while a transponder-equipped aircraft can (and should) certainly squawk 7600 in the event of a communications failure, there is no assurance whatever that the controllers have any way of seeing that squawk.

Remember that there are at least three kinds of radio failure: transmitter works and receiver doesn't, receiver works but you can't transmit, or both receiver and transmitter have failed. In the first case, there are two possibilities: you can transmit a carrier but no audio (as in, a broken headset cord) or no transmit function at all. In the second case, there are two possibilities: no audio (as in, a failed microphone) or no receiver function at all. And in the third case, it's possible that whatever killed both the rx and tx (for example, an electrical failure) may also have killed the transponder. So, there are several permutations, involving lost comm, halfway comm, and 1 1/2 comm. Thus, several scenarios suggest themselves.

Let's say you are in a radar environment when comm is lost. The controller may transmit to you and get no response. Sensing that you may still have receive capabilities, the controller may say "N12345, if you read me, squawk ident." If the same scenario but no radar, it may be "N12345, if you read me, click your mike" (if the tower is receiving carrier but no audio) or "rock your wings" (if no carrier is being received). Once one-way communications has been established, it then becomes two-way, the pilot responding through mike clicks, ident button pushes, or wing rocking. t's an old joke that if you are receiving nothing from ATC, and suspect their transmitter is out, you might transmit "ATC, if you read me, rock the tower."

Whatever the level of comm you may or may not have, in the event of losing clear, two-way communications, your best course of action is to get the plane back on the ground, and troubleshoot there. In some cases, this might involve leaving the pattern, flying to a non-towered field, landing there, and figuring things out. at your leisure (without burning avgas or running up the Hobbs meter).

Speaking of old jokes, you already know the transponder codes for VFR, emergency, radio failure, and hijacking. So, what's the transponder squawk for a failed transponder? :lol:

SSDriver · Joined: 15 Apr 2011 Posts: 31 Location: NJ

Paul,
Thanks for the very thorough answer!