Maybe it wasn’t the radio altimeter they were using to determine absolute height.

I believe what this is alluding to is pressure pattern flying, to determine where the winds were.

On those old weather radars, was there not a return that was evident at the bottom of the screen caused by a side lobe pointing straight down toward the earth’s surface?

I seem to recall that if you slected a short range on the set, with the scanner tilt angle set to zero, you could relate the ring to the range scale and it became a crude measure of absolute height. By referring to it occasionally, marking it’s position with with say a chinagraph, and seeing if it showed a climb/descent you would be able to determine the change in atmospheric pressure in the area you were flying in, by comparing it with your 1013 standard setting.

Very crude, but effective, and usable above the 2500ft. limit of the rad. alt.

Of course I could be talking a load of tosh…….

Nevetheless, El Al, did do some pretty impressive flying with their Britannia fleet. I also believe they felt they were held back from getting it into service as BOAC had to be the first, and in corporation style, were dragging their feet.

Ndege.