Originally Posted by fdx727pilot

Alright. Tony C comes through with the real facts. I've been itching to post this stuff, but thought I ought to read through the rest of the thread to see if someone had the real story. While I don't know what super early production 135s had in the way of extra windows, after 8 years and over 4000 hours on various 135 and E-3 models, Tony has his facts straight on the eyebrow windows and sextant port. And like others have mentioned, I've flown several 727s that had sextant ports, usually -100 models, built before omega and ins were available.