dublinpilot wrote:
Personally, I’d never land with just 11 gallons unless it was just a few circuits.
What if there’s a ton of “diversion” airports on the way?
On my longer flights, I’ve more than once landed with ~40 min of fuel (stretching the range), but with the following conditions:
- nice VFR
- plenty of airports where I could stop on the way (and around destination) for fuel.
I just monitor my route and never get myself in a situation where an airport is the “only airport” (or where a diversion due would make me really uncomfortable).
For instance, near my base (EGSX) there’s 2 other airports within ~5 minutes flying (one of them only for real emergency, but it is an instrument airport), and a couple more within a 15 flight (some of them with instrument procedures).
If you do your circuits from a single runway airport, you might be lured into a false sense of safety, and then a runway closure would equally put you in trouble.
The difficulty is knowing you have the 40 mins actually in the tanks.
I know of a guy who flew from Biggin EGKB to Corfu LGKR (TB20) and landed with 6USG in the tanks. No totaliser… That is 6.9% of his usable fuel, and he did it in an old TB (crap fuel gauges) and the analog fuel flow gauge is perhaps 10% accurate. So, he got lucky…
I once landed with 12 USG, and that was at the diversion airport (LDSP). Some years before that I did two flights of ~7.5hrs, both into unforecast headwind, both landing with 14USG. But my totaliser is ~1% accurate i.e. ~1USG.
@ Peter
I do have an almost new liferaft, never used 
Can’t stay in Samos, starting night rating Monday in Portugal.
Believe it, or not, my analog fuel gauge is quite accurate, all the 5 plus hours trip I did recently it went quite right.
I am considering other options:
Sitia, it would increase the trip in 1 hour, but would save me from FRAPORT and expensive handling.
Rodhes. Pilot feedback is really bad, same is Samos but at least I would add an additional airport to my ‘CV’.
Still have a couple of days to make a final decision.
Got a couple of interesting points, nothing that I liked or wanted to ear , as a summary, if the intention is to add stress to the trip, instead of enjoying it, its cheaper to go on airline.
What if there’s a ton of “diversion” airports on the way?
Well, not all diversion airports are the same. If you’re flying in an area that you know well and don’t feel under any pressure and you know the airport, then a diversion might be ok. But in this case, I belive that they are travelling between two differnt countries. I’m not sure, but I suspect some form of customs is probably required.
So you get flying, and the headwind is just a little bit more than expected. You still have enough to arrive, but less than you’d like. The correct decision is to divert and pick up extra fuel. But countering this your mind starts to think:
- I’m going to have hassle because I’m arriving without PPR
- I’m going to have hassle because I’m arriving without customs notifications
- I’m going to be delayed to my final destination now by the time on the ground, and the car hire/taxi that I arranged will need to be rearranged
- What are the opening hours of my diversion place? Will I be stuck here overnight if I don’t get out again in time?
- Will the delay to my final destination put me outside their opening hours?
- I’ll have to spend time climbing back to altitude
- I’ve extra landing/handling fees as a result
- I’ve probably enough fuel to make it ok
- I’m worrying about nothing. It’s just a couple of extra knots and I might make it up later
- If I just lean a bit more it should be ok.
- The guage is probably under reading a bit anyway.
- The guage looks show more in the tank than my fuel calculations show, so I’m doing better than I thought. So no need to divert based on calculations.
The consious thinking part of our brain is lazy, and hates investigating these sort of contingencies while trying to fly. So we naturally default to “no change in action”. So unless you are super disiplined, or set yourself clear “no progress beyond point X, unless fuel = Y” are will be awfuly tempted into making the wrong decision.
That’s why I prefer to keep fuel calculations on the ground rather than in the air.
If you do your circuits from a single runway airport, you might be lured into a false sense of safety, and then a runway closure would equally put you in trouble.
Runway closures are rare. But after you’ve arrived back to an airport once to find the runway closed, you’ll never be lulled into that false sense of security! During my training I remember hearing about a runway closure due to a damaged aircraft on the runway, and a number of students (including 2 solo) had to be diverted to airports that they would not normally be allowed into. I’ve always remembered that story! More recently I’ve arrived back to my home airport (with plenty of fuel I might add!) to be told that the runway was blocked because someone had burst a tyre on landing. It was a 10 minute delay. No big deal, I’d plenty of fuel. But if I was down to 6 gallons I’d be in serious trouble. So, no I never assume the runway will not be closed, even when doing circuits.
Also worth a mention that a diversion is a popular device for smuggling – because if say the police at the destination have been tipped off about your “cargo” (and usually they have been, especially after you have made a number of runs, but they are letting you do a few more so they can collect evidence) and are waiting for you, if you divert they won’t get to you fast enough.
That’s probably one reason why French police fly around in ~150kt turbine helis costing best part of €5000/hr to operate… The other is that it is a very very nice job 
So expect to get some “attention” if you divert somewhere, especially in certain parts of the world.
How do the numbers look if you cruise at 55% power? should get you some more margin. 11 gls on the the other hand is enough to lurk around the airport at holding power for close to 1.5 hours if push comes to shove.
Alternate for Skopje: Sofia is only 30 NM further than Ohrid and it has fuel.
As for enroute: 11 USG in a 10GPH plane is a bit tight but legal enough. If on initial contact with SKP you learn that they expect delay or are shut, you might be in a better position to divert to Sofia, otherwise it’s a really big airport with lots of concrete to land on. Even if someone parks an airliner right at the center point of the runway, in an emergency there should be enough real estate north and sout to land a SEP on. Or even on the taxiways if must be.
I had this happen once, years ’n years ago in Grenoble where a Air Inter Caravelle was stopped at the end of the runway. Even without declaring emergency we got cleared to land on the first half of the runway, which is more than plenty.
I would not plan with this little margin, I would plan for intermediate refueling from the get go. Arriving after 5h of flight tired and short on fuel is a good recipe for a bad disaster. Or in the worst case the diversion scenario of Airborne, in case the headwind is actually better than planned.
Do make sure you calculate with the usable fuel in you plane, on some types the difference is not insignificant. There is also the (I believe) Robin that crashed short of the runway some time back because the unusable fuel was reported in level flight, with the airplane’s attitude of full flaps on final the engine did not go on fumes. That difference is not reported anywhere.
I recently ended up doing a diversion after 20 minutes circling while the single runway was closed due to an accident. AT said on a number of occasions dont worry we expect to be open again in 5 minutes, but it never happened. I also recall being in the middle of France, making the stupid mistake of pushing on towards an active front. Escaping into good weather required some luck and fleet of foot with the plan binned and the need for a new plan in an unexpected direction.
The first was a comfortable experience because I had no doubt about the point to divert and had planned the diversion. The second was a very uncomfortable experience. Had the diversion airport suffered an accident on the runway the first may have become very uncomfortable, but I guess it is a really bad day to have two pieces of bad luck.
The only point of the story is I have never forgotten the feeling of flying not quite knowing if the fuel in the tanks was sufficient and how I would have feel writing off the aircraft and possibly worse in a field somewhere in France.
It has meant that I have never been tempted to have too few options since, and even the thought of arriving at a planned diversion with minimium fuel is uncomfortable, not because I am worried about the accuracy of my calculations, but because I imagine some problem at the diversion airport as well. I think GA usually gives you the options of rarely needing to be even close to reserves with very little trouble so I am inclinded to be very conservative. I dont fly for Easy or whichever commercial operator so I dont see why I should plan for minimium diversion reserves, even if they are legal.
Peter wrote:
Then, it is an old debate whether your alternate needs you to comply with any PNR/PPR requirements.
In this case, where it seems 50/50 whether I’d need the alternate, and I know this well in advance, I’d call for PPR. “Hello, this is G-ABCD. I’m planning a maximum range flight from AAAA to BBBB and I’m considering using you as my alternate in case of unforecasted headwinds. Is that OK?”
A phonecall like that most likely takes less time than reading through all the responses here. And hey, maybe you learn something useful. Something that may have you reconsider whether that airfield is a suitable alternate for instance.
