Ibra wrote:
you see how far things can go
That seems to be the message that comes across, so we can set expectations right about targets for buying a family airplane.
Besides, 600m and up gives you access to plenty of places: there are not those many you are leaving out. Even then some may be unsuitable for your planned load and weather.
So yes, you can push the boundaries, but mostly we are looking at a reasonably priced aircraft which ticks most of these boxes:
When you fly to unfamiliar destinations you use AIP numbers or Skydemon/GoogleMap in good faith…I would be careful with slope data and obstacles data (less 300ft are not shown and displaced thresholds), only airports that accept VFR public transport are required to publish reliable charts and data, IFR airports tend to have better quality data for “family trips”…
Ibra wrote:
I am inclined to fly C172 in 600m pavement with no issues, day & night, every weight and all weather, I would never fly twins in that…
It’s not just a question of runway length but also of obstacles. I fly from a field with 630 m grass. I have no problems flying a C172S at MTOM even at 30°C (ok per POH, but with very little margins on T/O). That’s because I know there are no obstacles on climb-out in either direction. (Oh, I and also check that I do get airborne after approximately the POH figure for take-off roll. If not, I abort. I haven’t had to do that yet.)
Ibra wrote:
Some ATO do that as well: they operate SEP on NCO against raw POH while they operate MEP on POH with margins plus CAT/PT add-ons
@Ibra, there is also a question of the published and the actual numbers, I as you know at EGTR the desclared TODA (as well as all other distances) is 651m. While in reality the full length of the runway, from the threshold of RWY 26 is around 820m, and the the first obstacle is more than 1km away from said threshold. If you take it at a face value, for AoC operations, then it has to be 651m, while if are OK to recognise the “unlicensed” part of TODA, then it is 1000m+.
I am perfectly happy with my N-reg 1981 Piper Seneca III which I also use as a family airplane.
Plenty of space and club seating is appreciated.
I paid a very reasonable acquisition price.
My maintenance bills after 2 years of operation so far are not eyewatering, and all systems (except radio altimeter) are in perfect working order (and I keep it working). So far I changed/repaired a vacuum pump, DME, autopilot, landing gear.
I fly LOP between 19 and 20 USGPH in cruise at 165 KTAS at FL100. Equipped with GAMIjectors and engine monitors, which I added both.
The twin mainly gives me de-icing and the additional protection of the extra engine at night, over terrain, water or low IMC.
I realise that flying a twin on take-off is more risky but the additional protection in cruise is appreciated (also by the family).
Although he is not a licensed pilot, my son knows how to land it in case I’d get incapacitated. He flies RH seat while the ladies enjoy the club seating arrangement in the back.
I don’t do grass (or very limited) as the prop clearance is limited on a Seneca.
I managed the expectation on that takeoff saying “it will be slow” (taxi was near full power and no stop with power checks done on pavement), we may not liftoff by half of the runway, actually we did not lift by 3/4, now I don’t fly grass with family all year along, hot summer & rainy winter, as simple as that, with few exceptions like Old Warden airshows or maybe to Venise 
…few years later, the wife, who flew hundreds of hours in gliders & motor-gliders, has objected to buying Maule 235 (base it in 500m private farm) or base a Mooney in LFFD (1100m grass within 5 min car drive), I am still allowed to fly grass strips in Guépard (ULM) or Jodel D112 (CNSK) when flying alone or with other pilots, so you see how far things can go 
Ibra wrote:
rejecting in C172S (180hp) with family: Abbeville grass has 1000m but was very wet that afternoon (pavement 1250m was NOTAMed not available, I still went inspecting it and took off on paved runway on the second attempt
What did the family think of your little take-off adventure ?
I once flew a C172S out of a damp grass airfield in the Czech Republic Hat u Hlucina (see note), three up, a lot of fuel, close to MTOW, having just landed prior.
I was flying with a local instructor who had been there several times before with this particular airplane, only 2-up and mid fuel, also when damp.
Rwy length was supposedly plenty with over 900m, but upon application of full power, it was very clear that acceleration was that of a snail. Since we had plenty of runway for the roll, we first tried lifting the nose, which slowed us down, then lowering it, which dug us more, so nose back up, but not so much, until after about 500m roll with airspeed going no higher than 35KIAS on the G1000, suddenly we started accelerating and I managed to take it just off the ground, then I maintained 3ft altitude until we had about 60 KIAS (I would not dare touch that grass again) and then completed the take off with some margin, but I had been ready to reject.
The instructor said he had never seen acceleration so slow on this airplane.
Possible morale on topic is : 100kg more (family) does make a difference.
(note) THis sounds very much like “Alucina” in Spanish which means “hallucinate” which is a word we use to express awe in a funny way…more or less the feeling all three onboard after that take-off….
I would not do anything on my own which I would not do with passengers.
I tend to hear that very often, it means never stall an aircraft on your own, near do steep turns, no field practice, no spins, no aerobatics, no open cockpits, no high altitudes, no gusts, no altiports…
If you are expanding your flight enveloppe you are likely do it on your own (anyone expanding experience with passengers need brain cells or soon will run out of people to fly with)
I would not do anything on my own which I would not do with passengers.
Well, the obvious exception is when it comes to IMC and scaring somebody who you would like to fly with you again You just never know how someone may react.
But that’s not a safety exception. That is just keeping everybody happy.
