The (somehow) unusual diversion of a US-bound Airbus 330 amid US Embassies threat

On Aug. 7, 2013, a Delta Airlines A.330-300, flying as DAL099 from Paris Charles De Gaulle to Detroit diverted to Amsterdam after experiencing an inflight problem.

The civil plane, N814NW had problems with flap extension/retraction so it circled over Norwich, UK, at FL250, to burn fuel and wait until Amsterdam was able to accept it for landing.

So far so good.

The aircraft eventually landed at Schipol airport and everyone safely disembarked the Airbus.


However, something weird happened as the Airbus burned off fuel to reduce its weight over southeast England: as airband monitors and aircraft enthusiasts noticed, the emergency sparked an unusual type of reaction by the British Air Traffic Control (ATC) agencies.

Indeed, Delta 099, that was already in positive radio and radar contact with the civil ATC, not only switched to a London Military ATC control frequency, but did also squawk a London Mil transponder code: in other words, it was momentarily handed over to a military ATC agency.

Usually, flights in trouble are usually kept on the same frequencies as long as possible (that is to say that radio frequency changes are reduced to the minimum – something that applies to most serious emergencies) but in this case the Airbus 330 changed both VHF frequency and transponder code to be managed by the military radar.

That said there are several reasons why this may have happened. Among them there is the possibility that the emergency wasn’t so serious and the aircraft was directed to circle in zone where other military traffic was operating; therefore it was switched to London Mil to reduce the coordination effort required by the civilian ATC to manage a plane in proximity with operative air traffic.

In fact a French Air Force E-3 “flying radar station” was reported circling in the same area (most probably a coincidence) and the controllers decided that it was better to have both the Delta and the French AWACS on the same frequency for proper deconfliction.

However, according to some readers there are speculations according to which the Delta 099 carried a U.S. VIP being repatriated following the US Embassies terrorist threat.

We are unable to verify the thruthfulness of such rumors, still we can’t completely rule out that the presence of a U.S. diplomat aboard and/or some kind of terrorist scare influenced the way the emergency was managed.

What do you think?

Image credit: curimedia,

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About David Cenciotti
David Cenciotti is a journalist based in Rome, Italy. He is the Founder and Editor of “The Aviationist”, one of the world’s most famous and read military aviation blogs. Since 1996, he has written for major worldwide magazines, including Air Forces Monthly, Combat Aircraft, and many others, covering aviation, defense, war, industry, intelligence, crime and cyberwar. He has reported from the U.S., Europe, Australia and Syria, and flown several combat planes with different air forces. He is a former 2nd Lt. of the Italian Air Force, a private pilot and a graduate in Computer Engineering. He has written five books and contributed to many more ones.


  1. Move along there, nothing happening here. An aircraft calling mayday in the UK will use 121.5 frequency which is handled by London Mil. The aircraft will be ‘handled’ on their frequency, rather than clogging up the usual airways frequency.

    • Most probably you are right. Still, what is interesting is that British milair monitors found it weird; enough to consider every option. BTW, the aircraft did not radio a mayday and did not declare emergency on 121.5 nor squawked emergency codes.

  2. Come on David, I thought you were smarter than this!

    Aircraft was orbiting outside controlled airspace as it was low enough to cause problems for London Terminal Control (EGLL/EGSS/EGKK/etc.), hence it was directed outside of controlled airspace for its orbit. As the area it was holding in is used regularly by military aircraft, it makes complete sense for the aircraft to be transferred to a military ATSU, as it reduces the co-ordination needed between controllers and thus their controller workload.

    Simple, really. No diplomats, no terrorists, just a couple of events that meant it needed to be handled by military controllers (controllers who are sat in the same building, and the same room in fact(!), as the civilian controllers who were handling it moments before)


  3. A U.S. VIP flying to Detroit? Very unlikely. ATC knowing a U.S. VIP was aboard? Probably also unlikely. If you spent your time monitoring UK military ATC frequencies, you’d want to say something special and unique happened while you were listening, but that doesn’t make it so.

    • I dont think ATC actually knew there was a VIP on board. At least that is not what the post says. It says “according to some readers…” I am curious to know if anyone tossed around any possible ID’s on this alleged VIP. The destination does not matter in these cases. There are times when someone that might have helped different agencies overseas come home and they just agree to send them wherever they want to go. Also, if true, Detroit could’ve just been one point on the VIP’s trip. Just because they are landing there does mean that is their final destination.

  4. Any possibility that circle is one of the air refueling tracks used by the KC-135s at RAF Mildenhall? It’s nearby, the right shape and size, and would be handled by London Mil.

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