Primarily for general aviation discussion, but other aviation topics are also welcome.
#1733584
A very interesting account. So he estimated his best glide speed as 160 kt based on 'feel', and used 'two miles for every thousand feet' as an estimate of glide range based on 'it being somewhere between that of a light single and a heavy'. Presumably he had a GPS (or other) range to monitor how well that estimate was working out, and it was working out ok. So far so good.

And then, if I understood it right, the approach was flown as a straight in (he was given a vector of 190 direct to the runway - runway 19 presumably, at Savannah), despite the fact that gear and flaps would make quite a substantial last minute difference to the descent profile. By the time he got the gear down, he was sure he was going to make the runway, descending through 1000', and then started introducing flaps.

Good job, it all worked out.

As someone with no experience of multi-engine or complex ops, but a lot of experience of glide approaches, my question is, how was he so sure he was going to make it? I can understand that if the range was reducing in proportion to the altitude, that would do ok for a gross estimate, but with gear and flaps at the end, with no adjustments possible if it came up short, there weren't many options with a straight in.

That's why we're taught to fly something of a circuit in the event of engine failure, so that we can tighten up or otherwise as the ground approaches.

The only reference to Citation glide ratios that I could find quickly is this one, which suggests a glide ratio of about 17. This means he could go about 2.8 miles for every thousand feet, not 2, as he estimated.

So It looks to me like he actually carried a lot of excess speed down that approach, and got rid of it with gear and flaps at the end, and did at least have over 2km of runway to play with. Since he didn't know his speeds or his glide ratio, it seems that there was at least an element of good luck involved.

Any thoughts from those that know a lot more about this sort of thing than me?
#1733675
An RAF pilot I knew talked of a "45 degree" approach for a radar PFL in a Hawk - I presumed that was shorthand for "1 in 1" - i.e. 1,000ft in 1nm (so actually 1 in 6 or about 10 degrees)?
#1733869
1in1 was Hunter engine fail procedure. When height in Thousands of feet equalled range in miles the gear was selected down and decent to maintain miles equals height to touchdown. The skill was getting the intercept at a clean glide of 500ft per mile with I believe 3000ft allowed for a 180 degree turn. As an ATCO a very interesting scenario.....
Lockhaven liked this
#1734056
On 2 eng types , we'd have a periodic double engine fail session in recurrent sim training .. Seem to remember the advice to be double the normal height at the Outer Marker [ 4 DME ] ... i.e. 2400' AAL. instead of 1200' . Rest is lost in mists of time , don't remember not getting in .

rgds condor .