Here is the Whelen PMA'd replacement.
http://www.aircraftspruce.com/catalo...helenpar36.php
http://www.whelen.com/_AVIATION/deta..._cat&head_id=6
I have had the GE 4594 100W bulbs (2 on each side) for around 4 or 5 years without replacing them. I have the pulse light selector and I use them day and night, smooth or rough field. Why are you blowing your bulbs? I would like to have the LED but I just can't justify the price when a $16 bulb lasts for over 5 years. The amperage drop with the LED is huge. I have the LED position lights and LED beacon. Love them and the drop in amperage is unbelievable.
Here is a demo
http://www.youtube.com/watch?v=3mLUV...78AUAAAAAAAPAA