Friday 5 July 2013

Oops!

I came across an interesting article while on my morning web perusals today. It struck a chord with me because I suspect it would be very easy to make the same mistake that this pilot did.  

Some basic background for you non aviation type people out there. This isn’t an in depth description, probably some omissions but it’ll get you through the article. A transponder is a little box that sits in your plane and basically helps ATC identify you.  It talks to their radar and sometimes other planes that have collision avoidance thingies installed.
To help with the ID process ATC usually issues you a discrete transponder code. They do this by telling you to “squawk” and then a number, e.g. “GSAR squawk 5306.” You then dutifully plug this number into the magic box. If they give you a code with an 8 in it they are messing with you!*

If they don’t give you a code and you are flying VFR then you squawk 1200 if you are below 12500 ASL and 1400 if you are above.
These are what are called “reserved codes.” There are others, especially for use in emergency situations.

7500 is reserved for aircraft hijackings. Basically it is meant to be a way of discreetly  letting ATC know that you are not the one in control of the situation
7600 is for comms failures. Often the transponder will work even if your radio doesn’t and it lets ATC know why you are ignoring them

7700 is for emergencies, because when bits are falling off the plane, everyone has time to punch in a transponder code!
Transponders tend to be very reliable, the people operating them not so much. Sometimes you forget to switch it on to the “ALT” setting and then ATC can’t find you. I’ve had this happen to me, and I’ve heard it happen to other people too. ATC are usually okay about it, I’ve heard them say

“Recycle your transponder please” or “XXXX confirm your transponder is on”.
I have NEVER heard them say “squawk altitude,” which is what they said to one unfortunate pilot.

Who happened to be at 7500ft at the time.
You see where this is going?

Yep,  he was met with a full armed response on landing, despite being the only one in the plane!** 
OOPS!

This is why we use standard phraseology people!

 

* squawk codes are OCTAL based, they use 0 through 7. Sad fact: I am capable of doing basic arithmetic in OCTAL, and Binary and HEX.

** Our Airlaw instructor in ground school gave us the excellent advice "if you ever have to squawk 7500 in a 150 then you need to choose your flying companions more carefully!"

 

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