MAYDAY during diversion

[F-16GUY]

So since the original thread was closed, I will have to ask my question here. I did not mention any company names so I hope this will not be closed as well.

Can someone explain this to me?

Obviously military aviation as I am used to, is different from commercial aviation, in respect to purpose, rules and regulation. However, the built in safety margin and more specifically the reason for it to be in place, should in my opinion be the same. For us in the military, any diversion is a planned event, and a planned event will never require a MAYDAY call. We always carry extra fuel to enable us to divert. If weather dictates that we carry enough fuel so as to be able to divert in case we can’t land at the planned destination, we do exactly that. If its VMC conditions, we still have a requirement to carry enough fuel, so that we can divert to the nearest suitable airfield, in case the destination runway closes for whatever reason, just before we land (i.e. the plane in front of me crashes on landing). Only situation I can think of that will require a MAYDAY is if the weather changes unexpectedly (below landing minima) at both the destination and the alternate, and we now have to fly to an other airfield which will result in landing with less then minimum fuel.

So having multiple aircraft from the same company, declare MAYDAY during diversion, for any other reason then unexpected worsening weather, at both destination and alternate, just sound to me like pure planning or inadequate rules/regulation/procedures. Reminds me of a situation with a carrier that had multiple diversions with MAYDAY and low fuel, during a very short duration of time, in Spain some years ago...

Or is there just a big difference between our two worlds of aviation?

[giggitygiggity]

Do we know they declared a mayday or did they just set 7700. They might have declared pans or minimum fuel and ATC asked them to do this. Genuine question, I don’t know.

Of course it would not be normal but the system worked and everyone landed safely.

[F-16GUY]

Originally Posted by giggitygiggity

Do we know they declared a mayday or did they just set 7700. They might have declared pans or minimum fuel and ATC asked them to do this. Genuine question, I don’t know.

Regardless of a MAYDAY or 7700, the question still remains: Is a diversion a planned event or is it an emergency?

[Bob Viking]

F16GUY

I’m military through and through and if I had to divert for fuel (I have a couple of times) I would declare a PAN as a matter of course.

The reason is that, upon reaching my diversion airfield, I would then be out of options and would need landing priority. This assumes that at the start of my diversion I was at my minima (I was when I did it for real).

When you reach your planned alternate you do not carry enough fuel for another alternate so it is your last chance saloon.

The question of PAN vs MAYDAY may carry a personal (or company SOP) element to it. In my mind (without giving it too much thought) it would depend on weather and traffic. If it is a VFR transit to the alternate and light traffic a PAN would suffice. If the situation was making me twitch then a MAYDAY may be required.

BV

[F-16GUY]

Originally Posted by Bob Viking

I’m military through and through and if I had to divert for fuel (I have a couple of times) I would declare a PAN as a matter of course.
BV

Why would you have to divert for fuel? Fuel leak? Underflown Bingo fuel? That sounds to me like a different and unplanned situation obviously requiring some kind of urgency. The question is regarding planned events.

[giggitygiggity]

Originally Posted by F-16GUY

Regardless of a MAYDAY or 7700, the question still remains: Is a diversion a planned event or is it an emergency?

A diversion doesn’t need to be an emergency. In the last two years I’ve diverted twice, one of which was under a pan. Also a diversion to your nominated alternate should ALWAYS be planned. Obviously they didn’t want to divert but given the situation presented, opted for plan B and did so safely. London ATC will then ask the aircraft their endurance and prioritise them accordingly. If the level of priority given is incompatible with their fuel state then they will first declare ‘minimum fuel’ and then potentially a pan or a mayday. The controller might ask them to set 7700 as it is a conspicuity code that will enable the other controllers of lower, upper or adjacent sectors to see them or see them coming.

[F-16GUY]

Originally Posted by giggitygiggity

A diversion doesn’t need to be an emergency. In the last two years I’ve diverted twice, one of which was under a pan. Also a diversion to your nominated alternate should ALWAYS be planned. Obviously they didn’t want to divert but given the situation presented, opted for plan B and did so safely. London ATC will then ask the aircraft their endurance and prioritise them accordingly. If the level of priority given is incompatible with their fuel state then they will first declare ‘minimum fuel’ and then potentially a pan or a mayday. The controller might ask them to set 7700 as it is a conspicuity code that will enable the other controllers of lower, upper or adjacent sectors to see them or see them coming.

That makes sense for a single aircraft. But I think that when multiple aircraft from the same company are involved, something just doesn't add up.

[giggitygiggity]

Originally Posted by F-16GUY

That makes sense for a single aircraft. But I think that when multiple aircraft from the same company are involved, something just doesn't add up.

The flight plan will include a few different parts to the fuel plan. The taxi fuel, the trip fuel, the alternate fuel and the final reserve fuel. In addition to those there is the contingency fuel. Most airlines use statistical contingency fuel (might be called something else) and it gives the crew an idea of how much extra fuel is routinely used on a route from A>B (an average of hundreds of flights to keep it simple). On a thursday in March, this will probably be a low figure, on a saturday in August, it will be a high figure. It should give the crew a decent starting point for thier fuel decision and encourages them not to take less as obviously the airline want the flight to reach the destination.

Crew will take extra fuel if the weather looks bad (today it didn't) or there are ATC delays (such as strikes, equipment failures etc), or they'd prefer an extra comfort margin for whatever reason. Maybe the captain is new and wants a better margin for another 5 mins of thinking time, but they don't just fill the tanks. The two aircraft that ended up diverting came from performance limited airfields (short runway, lots of hills etc - Look up Innsbruck for pretty pictures) so they can't just put on an endless supply of fuel. They do have other options, but business sense would dictacte that rather than offload passengers on a day with decent weather, on a quiet day of the week at a quiet time of year.

Don't forget that easyjet are BY FAR the largest operator into this airfield and therefore any issues (a sudden closure of the runway) will far more likely hurt them than another operator.

[Del Prado]

Don’t forget you have to get acceptance from the diversion airfield before you commence diversion.
What if your original destination is unavailable and you’ve held for 10 minutes waiting for the diversion airfield to accept you? Do you carry on holding? How long for?
Once you suspect you may land with less than 30 minutes fuel you must declare a Mayday and you can then divert with priority.(Mayday not Pan)

I imagine in the military, if you wish to divert you make the call and go immediately but in the commercial world a busy airfield might not have the capacity (or handling) to accept you.

The fact that it was the same airline may be down to the fact they are the largest operator there, no other reason and certainly not anything more sinister or foolhardy.

[giggitygiggity]

Originally Posted by Del Prado

Don’t forget you have to get acceptance from the diversion airfield before you commence diversion.
What if your original destination is unavailable and you’ve held for 10 minutes waiting for the diversion airfield to accept you?

This is a good point. During storm Dennis or Kiara (cant remember) I heard a Vueling on the radio. They did 2 windshear go arounds and then requested a divert to MAN (150nm away). ATC didn't tell them their diversion was accepted for approx 20 mins and left them painting lines in the sky for that time in a poor position. Still south of LGW they headed north and then declared a Mayday and landed in LHR. You don't automatically get your nominated alternate as the UK is very capacity limited. On a nice day with decent weather, that shouldn't be a problem. Worst comes to worst, you declare minimum fuel, then a pan, then a mayday as required to get what YOU want. It's ATC are essentially triaging flights.

[flocci_non_faccio]

Why would you have to divert for fuel?

In the commercial world, we don't routinely carry additional fuel "just in case". It is entirely possible to have planned a flight perfectly adequately from a fuel point of view, arrive at your destination with your contingency, alternate and final reserve fuel intact, and through an unforeseen set of circumstances end up in a situation where you will land with less than final reserve fuel (30 minutes, or approximately 1200KG on an A320CEO). If you know that you will land with less than final reserve fuel, a MAYDAY must be declared.

I’m military through and through and if I had to divert for fuel (I have a couple of times) I would declare a PAN as a matter of course.

I can't comment on the military SOP in such a situation, but a PAN for fuel is no longer correct phraseology in the UK.

[TheEdge]

I dont know about the EZY flights in subject, but sometimes we do fly with a RCF (Reduced Contingency Fuel) approved Flight Plan and a declared Decision Point (DP) where we do check our fuel levels and decide whether to divert to the agreed ALT or not based on the Flight Plan, thats a normal procedure that doesnt require any MAYDAY or PAN.

[VinRouge]

Originally Posted by F-16GUY

So since the original thread was closed, I will have to ask my question here. I did not mention any company names so I hope this will not be closed as well.

Can someone explain this to me?

Obviously military aviation as I am used to, is different from commercial aviation, in respect to purpose, rules and regulation. However, the built in safety margin and more specifically the reason for it to be in place, should in my opinion be the same. For us in the military, any diversion is a planned event, and a planned event will never require a MAYDAY call. We always carry extra fuel to enable us to divert. If weather dictates that we carry enough fuel so as to be able to divert in case we can’t land at the planned destination, we do exactly that. If its VMC conditions, we still have a requirement to carry enough fuel, so that we can divert to the nearest suitable airfield, in case the destination runway closes for whatever reason, just before we land (i.e. the plane in front of me crashes on landing). Only situation I can think of that will require a MAYDAY is if the weather changes unexpectedly (below landing minima) at both the destination and the alternate, and we now have to fly to an other airfield which will result in landing with less then minimum fuel.

So having multiple aircraft from the same company, declare MAYDAY during diversion, for any other reason then unexpected worsening weather, at both destination and alternate, just sound to me like pure planning or inadequate rules/regulation/procedures. Reminds me of a situation with a carrier that had multiple diversions with MAYDAY and low fuel, during a very short duration of time, in Spain some years ago...

Or is there just a big difference between our two worlds of aviation?

No difference. If you expect to land below Final Reserve Fuel (30 mins at 1500’) it’s black and white in the CAP. Mayday. If any further delay could lead to you landing below reserve fuel, it’s Minimum fuel.

big difference in civilian aviation I suppose is you can commit to destination once certain requirements are met. Never did that in the military, done it a few times as a civvie.

[Denti]

Especially if a busy airport like LGW has some issue affecting the landing rate, you will get a lot of diversions fast and those diversion airports and their ATC will become saturated equally fast as well. There is no doubt that ATC in the south of the UK is absolutely top notch, but even they are human beings and a lot of diversions do require a lot of extra work.

Considering the airline in question has something like 65 to 70 aircraft based in LGW, even a short problem will invariably involve quite a few aircraft. If it was not anything you can plan for, they probably did not take extra fuel to account for something like that.

According to the rules there is basically two levels of low fuel warning from an aircraft to ATC: after having committed to land at a certain airport you may end up with less than final reserve fuel in case of any change to routing or clearance, it is "low fuel", that is not an emergency and the aircraft in question will not get preferential treatment. Well, it might, but there is automatism there. The next level is, if it is certain that you will land with less than final reserve fuel, it will go directly to "MAYDAY Fuel". The difference between low fuel and mayday fuel is surprisingly small.

Standard fuel planning does not account for any holding at the destination, or delay vectors while ATC sorts out a diversion and so on. It is departure to destination including approach and missed approach, diversion to alternate, and then 30 minutes of holding (final reserve). On top there is of course fuel for taxi out and contingency, but that can be as low as 5 minutes and can be used at any time after off blocks for any reason, so it might not be available at the destination.

I had it myself, waiting 15+ minutes until ATC had sorted out a diversion, it can happen. And the fuel used during that time does not have to be planned for, so it can dip into final reserve very fast indeed.

[VinRouge]

Originally Posted by F-16GUY

Why would you have to divert for fuel? Fuel leak? Underflown Bingo fuel? That sounds to me like a different and unplanned situation obviously requiring some kind of urgency. The question is regarding planned events.

bingo is a military term. The regulator has strict rules regards minimum fuel. So how many minutes flying is that in an F16?

if you had committed, or were planning to land close to reserve, and something changed (drone alert is my biggest thought here or short term runway blockage, you may end up in a mayday fuel whilst enroute to diversion. The drone thing has influenced how I plan - I will always have another piece of tarmac up my sleeve just in case.

London is well served anyway, with Stansted, Gatwick, Heathrow, Bournemouth and Birmingham in close proximity. All are good for a wide body.

[VinRouge]

Originally Posted by TheEdge

I dont know about the EZY flights in subject, but sometimes we do fly with a RCF (Reduced Contingency Fuel) approved Flight Plan and a declared Decision Point (DP) where we do check our fuel levels and decide whether to divert to the agreed ALT or not based on the Flight Plan, thats a normal procedure that doesnt require any MAYDAY or PAN.

most airlines fly off stat contingency these days. Enroute alternate is something we only seem to do when building the stats on a new route.

[Check Airman]

Unless the definition of emergency has changed, why would a diversion ever fall into this category?

[IRRenewal]

Originally Posted by Check Airman

Unless the definition of emergency has changed, why would a diversion ever fall into this category?

Quote from a training handout:

"The “MAYDAY” declaration is used when all opportunities to protect final reserve fuel have been exploited and in the judgment of the Commander the flight will now land with less than final reserve fuel remaining in the tanks."

The diversion itself is no reason to declare a MAYDAY, it's down to how much fuel you have left.

[Too Few Stripes]

EASA OPS CAT.OP.MOA.280 (b)(3)
The commander shall declare an emergency when the calculated usable fuel on landing, at the nearest adequate aerodrome where a safe landing can be performed, is less than final reserve fuel.

[jmmoric]

Challenge is when more aircraft does it simultaniously, declare emergency.

One aircraft declaring emergency is relatively easy to handle, but if several aircraft follow, due to a "he did it, then I can do it"-mindset, it may spark a lot of problems, especially for those who are in the most dire situation, since they may end up behind someone who could have been in holding for an additional 5-10 minutes.

Not saying the mindset is something that is likely to happen, it's may still be a danger.

Like LookingForAJob said.