Today I flew on an Embraer 190 of Kenya Airways. Checking in the tech specs this aircraft has a range of roughly 2900 km. Considering it is built in Brasil, I was wondering how do they deliver it to Africa since they would have to cross the Atlantic Ocean which I suppose is more than 2900 kms of range it has available.
Do they add temporary tanks and, of course, by flying the aircraft empty get more range out of it?
Sometimes they do add temporary tanks. Here's a picture of what Hawaiian Airlines had to do to get their fleet of 717's over the Pacific because they did not have the range.
I don't have the answer to your question specifically, but I would guess they either add temporary tanks and go from SBNT-GUCY which is not much further than max-range, or take the long haul through the US and Europe.
There's a Cranky Flier blog post about this.
First of all, yes, there are tricks to get the aircraft fly farther. You can leave the payload out, this will allow you to fill all fuel tanks without reaching the maximum take-off mass. Less mass means less induced drag, so you can fly higher and at a lower fuel flow. It will also allow you to install temporary tanks to carry even more fuel than the aircraft was designed for. That is how small GA aircraft get transferred from the US to Europe.
This is a typical payload-range diagram with the three distinct points: Maximum payload, maximum fuel and transfer range with no payload. The slope between maximum payload and maximum fuel points shows how well the additional mass of fuel is converted into range (mostly due to engine efficiency), and the slope of the lower segment between maximum fuel and no payload shows how much the weight reduction increases range (due to induced drag reduction).
In jets and turboprops, you can use higher-density fuel (PDF) which gives you more energy per volume in order to get a few more percent of range. And if all fails, you can disassemble the aircraft and ship or fly the parts over. If the range is not sufficient, the plane will be small enough and will be designed for easy dis- and reassembly.
Short Belfast being loaded with JetRanger (own work)
I flew in a brand spanking new Airbus A320 on its maiden voyage from Toulouse, France to New York about 13 years ago. We had to stop in Iceland and Newfoundland for fuel before heading to New York.
At Oshkosh every year (EAA Airventure) I hear about pilots crossing from Africa (the furthest western point) to the furthest eastern point of Brazil in a single engine small plane. So I'm betting the jet can easily make that crossing. They do have to put down at the first airport to get fuel. That flight is not one I'd care to do...
An Australian company I used to work for purchased a Jetstream 41 turboprop off an American seller. With a range of only about 1400 kilometres, there was no chance of safely making it across the Pacific. So the ferry flight went through Canada, Alaska, Russia, right down through south Asia to northen Australia.
So the answer is, when they can't extend the range far enough, they'll go the long way!!
I was chatting to one of the Pilots of Maldivian Air Taxi a number of years ago, who fly Canadian built Twin Otter's. He remarked that one of the more interesting jobs for that carrier was the "Overhaul flights". A few pilots spend almost all year ferrying their aircraft back and forth to Canada.
I don't remember the exact route but it involved lots and lots of stop-offs for fuel.
