This from Scott KD7PJQ, via the SolidCpyCW mailing list in response to a thread on the reasoning behind Q signals:
Although this doesn’t explain a rhyme or reason to the Q signals, I thought the following was very intersting. From Bill Neutzling’s B-24 Liberator Site. The site includes training manual for radio operators–the Radio Operators’ Information File (ROIF). It has two pages explaining Q signals. (To view the pages, you have to go to the website by clicking on the link above, click on the link to the “Radio Operator’s Information File,” the page down to “Page 15-1″ and “Page 15-2,” and click on those links….Dan)
There are a few I recognize. I’m going to see if I can dig up an old copy of FM 24-13.
This list is missing a few that are common in amateur use, such as QRP and QRO, but there are others that are useful for use in aviation. For example, QAA means, “I expect to arrrive at …..(time).” QAL means, “I am going to land at ……… (or …………).”
There’s even a QLF! According to this manual, QLF does not mean, “I’m sending with my left foot,” but rather, “Your frequency is slightly (or ………. kcs) low.”
I did a Google search for “FM 24-13,” and found a reference to The Able Baker Story. This page noted the full name, “Basic Field Manual FM 24-13.” When I plugged that into Google, I got a second reference to the Travis Air Museum, aka the Jimmy Doolittle Air and Space Museum. On their book references page, they list FM 24-13 as being in their library. Perhaps we could get them to photocopy the Q signals pages from the manual.