What you haven't considered is that after the "runway" at REG there are a couple more kilometers of "runway" before you encounter any obstacles (depending on the runway). In actual fact, the "runway" at REG just consisted of a line of tyres placed on the desert surface; until recently there was no difference in surface between the "runway" and the surrounding desert which is sufficiently hard to support the Let's weight for TO and landing purposes. If there's any place I would rather lose an engine on take off, it would be at REG.
Sometimes the textbook answers that may work in an airline environment need to be tempered with a bit of common sense. Does the "runway" end just because there the line of tyres comes to an end?? Is that thing a "runway" at all????? Ain't easy to spot in a sandstorm, I can assure you.
I think this photo going into REG pretty much sums it up:
However, Maxrated, you do touch on an aspect of operating the LET compared to the Twin OTTER. Having a Max TO weight greater than 5700 kg, the LET has to comply with the more stringent requirements of part 121.
I have never flown the Twin Otter so cannot comment on what it's like to fly. What I can say though is the LET is a hoot to fly, with nicely balanced controls and really no handling vices that I have encountered. Personally I prefer flying the L410 to the L420, the L410 having lighter controls with more feedback.
I am often astounded by the short field landing capabilities of the aircraft, not quite matched by the short field TO abilities - you can land in a shorter strip than you can get out of! Short field landing technique consists of hitting full reverse and spoilers on touchdown with firm braking. The spoiler really dump the lift and increase the braking effectiveness. Some captains have been known to apply spoilers just before touchdown (if it looks like its going to be a greaser) to bring an overconfident co-pilot down to earth - literally! The anti-skid significantly shortens the landing distance on a dirt strip - you can feel the brakes "pumping" as the anti skid kicks in and out. Ever tried taking off across that 20m wide runway, Maxrated?!!! Hope you had a nightstop kit.
I reckon the Let will give the OTTER a run for its money in the short landing department, although the OTTER will get out of shorter strips due to its lower Vr. Then again, if you have at least 900 m to meet the Accelerate Stop / Go requirements I would rather have the extra speed and comfort of the LET.
As far as maintenance goes, the LET is a more complex aircraft than the Twin Otter, so obviously the extra systems require additional maintenance. The LET maintenance schedule consists of a series of 10 day inspections followed by a 300 hour, 1200 hr and 4800hr inspection of increasing intensity. The Twin Otter has a couple of ADs out on the airframe (NDT testing of the wing struts for instance and corrosion inspections on the wings) that make it an expensive aircraft to maintain.
As for temperatures, is the Otter certified for operations above 50 degrees? Like any aircraft, you are going to lose performance in the extreme temperatures we have to endure out here - I am sure the Twotter is not a rocket ship when the mercury creaps into the 50s. Then again, water injection giveth back what the heat taketh away....thank God (and LET) for that!