Why do ATC always ask for a reason for a non-emergency diversion?
 

If we have to divert for a (non-emergency) motive, ATC always ask for a reason. Why is this? Is the reason given logged anywhere? Are some reasons deemed unacceptable?

Most occasions that this has happened to me have been due to passenger request - is this an acceptable explanation?

You don't say where you are but I imagine it is a local requirement. Eg provision of customs and handling facilities. I'd never heard of it and I was in the game for a good long time.

It has happened to me twice in France, once in Italy, and once in Morocco. I don't think that it is a customs or handling issue - I have always had to sort that out myself by satphone (or GSM - but don't tell anybody!).

Possibly to advise down route units of flight plan changes/cancellation!

They might have to relay the request to the airfield to which you want to divert.

Yes, I appreciate that ATC will need to reroute and advise the new destination airfield, but why do they need a reason for a (non-emergency) diversion?

When I have had to divert for non-emergencies, the real reasons have been banal. Once the boss's secretary had omitted to warn me of a last-minute change of destination and I only found out when the boss tapped me on the shoulder and asked why Paris (his new destination) was disappearing behind the left wing 45000 feet below. On another, striking Spanish ATC held us down at FL250 right through Spain meaning we were burning too much fuel to complete our flight which was planned at FL410. On another (in a toiletless aircraft) the pax was caught short. I always hesitate to give the reasons for the diversion in case ATC refuse.

I have been met after a divert by the local special branch types.

Apparently diverting mid route for none emergency is one of the flags they use to spot dodgy going ons.

Some countrys care others don't.

<<I always hesitate to give the reasons for the diversion in case ATC refuse.>>

They cannot.

Mad Jock
Good point, I forgot about that aspect.

Cheers

We're a curious lot and anything out of the ordinary piques that curiosity? If you tell us the mundane reason then we know there is no potential for it to develop into an emergency.

In my experience as a controller I would say that neither myself nor the controllers at the diversion airfield are interested in a reason for a non emergency diversion. Indeed when this occurs, most pilots will state that it is for "operational reasons",and that is all the info that ATC need-you want to divert,it is otherwise ops normal. Although if an airport is pushed for parking space,they may only accept diversions for emergency,in order to keep their own operation moving.
When I do have to ask a pilot for a reason,the request has usually come from the airport ops people. I guess they need to know what facilities you need to use,how long you will be there for,whether they have enough space to park you etc etc.

In the UK en-route we will ask so that we can tell the destination airfield if there is any problem, it's usually something they will ask anyway.

"Operational Reasons" is enough for us and it's just to ascertain you don't need any special treatment. If it's in another country then we'll just alter your flight plan so any other agencies on your routes, new or old, are expecting you, or not, and to make sure you're not subject to any flow restrictions anywhere

Any number of reasons, but the one which comes to mind is capacity. These days, many airfields are capacity constrained and simply cannot handle unplanned arrivals (unless emergency exists). eg. the international airport I work at (as per NOTAMs).

It could be as simple as assessing what services will be required. Is it a tech stop, a toilet stop, or an arrival?

Thanks for the replies - good to hear that "Operational Reasons" is good enough and I don't have to broadcast to the world that the pax needs a wee!

The 'reason' needs to go in the OPS log - citing 'Operational' is absolutely fine and more than meets the needs of our curiosity.

As an operational centre we will never refuse your request, although you might be on a sticky wicket later on as there are some airports that will only accept you as a diversion in case of emergency.

IIRC EDDF will only accept diversions from EDFE if they declare emergency for example.......

Telling us the reason will also help us to dictate the priority we give to your request..... in busy traffic an 'operational' diversion may well not be at the top of the pile of things to do, whereas a medical diversion etc will obviously get processed ASAP.

ATC ask for a reason because when they pass on the fact you're diverting, they'll almost certainly be asked why, so they need something to tell whoever is meeting/handling the flight.

Scenario: big delay on intended route/destination........possibly draconian level cap as well......file a different route to different destination and divert en route!!!! I'm sure that has never happened...but if it ever did and then happened again and seemed to become a normal operating practice.....one might become suspicious. In real life though, a controller might be genuinely concerned in case he/she can help in any way, because we know that not all diversion reasons will require an urgency transmission. Things aren't always black and white in ATC....if we can help then we will.....for whatever reason......besides..we might know of a closer loo!!!

Exactly as chevron said. You can be assured that as soon as you pick up the phone to the next unit they will ask why. I personally want to know because I have had too many instances of crews not telling me the 'whole truth'. One particular instance was a biz jet who suddenly decided to drop in to a near by airport and said pretty much nothing. Turned out he had shut down an engine.

Anyone who has worked in the Sandpit will know you can't do anything without a reason, and the local Military in every country or state question everything!!! Verci you and Plazbot should be fully aware of that.:{

Because we are very curious and like to know everything... :E

Seriously, it already happened that an a/c requests diversion because of a tech problem, but doesn't want to say so, so that he is not charged with all the assistance stuff on the ground. :ugh:

Then we like to know what's going on, if we can expect something that goes wrong, and maybe we advise the emergency services.

We also are going to be asked the reason why, so better ask first..