How dangerous is a single runway, major airport?
Well I guess that was catastrophically demonstrated at Los Rodeos, Tenerife on a Sunday in March 1977.
Sunday was a busy day anyway at TCI (as Tenerife Norte Airport was known then) with many holiday jets coming in all day from all over Europe, Scandinavia, and the UK, often including many big jets 707's CV-990's, DC-8's, VC-10's and the new wide bodies 747, DC-10 and TriStar's.
TCI has a single runway operation 12/30 that had been lengthened to 3,000m, with ILS and a parallel Taxiway. No ground radar.
Throw in the mix on that day a terrorist incident on the nearby island of Gran Canaria meant that the Las Palmas Gando airport there was closed to all inbound traffic (again, Las Palmas is very busy on a Sunday) thus TCI saw many aircraft diversions coming to land there.
LPA ATC would not allow inbound aircraft to hold over the sea, even if they had enough fuel reserves (Of which Pan Am evidently had)
The consequences were was that TCI was soon swamped with very large jets parked up to a maximum on all of the available apron ramps, with the taxiway now also used for parking both the KLM and Pan Am 747 diversions.
KLM's passengers were disembarked into the Terminal but Pan Am's did not.
LPA soon re-opened and clearances were given to start clearing departures, and during this time the notorious foggy weather and low visibility started to close in over the airfield.
Pan Am was ready to go but did not have wing tip clearance to taxy safely past the KLM parked in front.
KLM reboarded, but 4 pax were lost in the terminal.
The KLM Captain then decided to tanker fuel to save time fuelling at LPA thus caused Pan Am more delays whilst KLM now waited for a fuel bowser.
The lost 4 pax (a family) were rounded up and were boarded on the KLM 747.
KLM was finally ready to go...But by now the weather was appalling, fog had quickly closed in, and the Tower could not now see the aircraft.
The controllers plan was for the 2nd 747 (Pan Am) to taxy down the runway behind the KLM and then exit it using one of the transverse taxiways which should clearly/ideally have been at exit C4, a 45 degree left turn, ideal for a 747. This would clear the runway for the KLM plane to take off.
Other aircraft were waiting on C1 and C2 to also join the runway and backtrack, after both 747's had departed.
One of the 747's Crews was completely unfamiliar with TCI airport, it's ATC and that 3 languages were being used.
Most of the rest of that Sunday afternoon is infamously ingrained to History, save to say that would we today allow in almost zero Vis & poor RVR two 747's full of passengers to both taxi down an active single runway together to backtrack the full length ?