Originally Posted by Speedbird876

Before landing, on approach to various airports, I have heard a sound. I thought it was someone's mobile phone picking up coverage and sending an alert.

It's like a text message alert but it has five tones. It's not really beep-sounding more alarm-sounding.

I had just put it down to someone's mobile phone but I've heard it on many flights (mostly BA but others too, I think). I don't remember hearing the sound on the ground and I don't connect it to a brand of phones or anything. Also, it's not like there are many different ring-tones going off together. This one in particular stands out.

Any ideas?