9000ft/15nm/@ 90kts, 3nm/1000ft, that works out to 27nm by my calc.
15nm should have been easily achievable, even at 750fpm, which should have given 3nm/1500ft, giving a straight line glide of 18nm.
sounds like they got very lucky, especially as they were picked up @ 11 miles - 4 miles over 9000ft? they're a mile and a half up for goodness sake!