Lesson one, I imagine, in the airline maintenance engineers' course, goes something like "It's much easier to fix a fault in the cabin when the passengers aren't on board".
The unfortunate engineer with more than a passing resemblance to Che Guevara, whose fluorescent jacket announced him to work for Tunisair Technics, may remember New Year's Day 2012 as the date he was obliged to mend the plane in the full glare (in both senses) of passengers keen to get home. But with competition shut out, Tunisia's national airline has little incentive to perform better.
One reason Tunisia has slipped so far behind Morocco in attracting tourists is the absence of "open skies". Britain realised three decades ago that liberalising aviation and encouraging competition benefits everyone.
Starting with British Midland (sadly, soon to disappear), travellers learnt that expanding choice cuts fares and compels incumbents to improve.
Across much of the Mediterranean, flights are as frequent as the market will bear. But some restrictive bilateral agreements, where a route is carved up between "flag carriers", survive.
One example is between London and Tunis. While the Moroccan city of Marrakech has five daily flights from London, with furious competition between four airlines, the only scheduled carriers allowed on the route to the Tunisian capital are British Airways, which flies five times a week from Gatwick, and Tunisair, with the same frequency from Heathrow. Inevitably, fares are higher, and service poorer than on comparable 1,100-mile routes – as Tunisair demonstrated on my trip last week.
The outbound flight from Heathrow was an hour late, though no-one connected with Tunisair seemed inclined to explain why or apologise. Coming home on the first day of 2012, the airline's performance proved little short of comic. I was among a party of five. Getting seats together was always going to be tricky, but the "boarding-pass poker" hand dealt by the check-in agent was as bad as it gets: 9B, 10B, 15A, 16F and 18E.
When I pointed out that two of the party were young children, the response was a shrug: "Tell the gate staff." The buck-passing continued in the departure lounge: "Sort it out on board." Fortunately there were enough cooperative souls on board to turn it into a winning hand: three of a kind, in the shape of three seats together in exit row 10. (The cabin crew were unconcerned that two of the occupants were under 12.) And it provided an excellent view of what then transpired in seats 10E, F and G.
At the scheduled departure time, a maintenance man was looking at the port engine, which had the aviation equivalent of the bonnet up. Some magic involving adjustable spanner, an oily rag and WD40 seemed to do the trick. But half-an-hour after we were supposed to have left, came news of another problem: "We will be delayed for 30 minutes for a technical check."
Messrs 10E, F and G stood in the aisle as Mr Guevara the engineer moved in to do battle with spanners and wires and bulbs. He eventually fixed the problem, to a smattering of applause.
The plane arrived safely at Heathrow, 75 minutes late. And I arrived at a couple of conclusions: Tunisair is further proof of the aviation theory that, the more welcoming and hospitable a country, the less those qualities are demonstrated by the national airline; and that passengers are regarded as an irritating encumbrance, without whom the whole operation would run much more smoothly.
If the new government sees sense and liberalises aviation, Tunisair may yet get to enjoy that serene state of affairs.
For transportational inadequacy, look no further than Heathrow Terminal 4, where the Tunisair flight arrived 75 minutes late. Since British Airways moved to Terminal 5, the shortcomings of its old long-haul home have been exposed – especially in the links to the city it is supposed to serve.
Anyone who is pressed for time after a delayed flight cannot take a Heathrow Express train to central London, because they have switched to BA's Terminal Five. A stopping train to Paddington runs only twice an hour.
In my experience, Tube trains come around the Piccadilly Line loop to Terminal 4 with about the same frequency as total solar eclipses. When finally I found a Tube, it was going only as far as Acton Town – where, at least, the choice of connecting trains trebles. Unfortunately, the driver declared he would be going no further than Northfields. I finally arrived in the centre of the city that will welcome the world to the Olympics in six months' time a full two hours after touchdown.