Commercial Flight Diversion - Loss of Navigational Capabilities?

Yesterday my son-in-law and his family were returning from a trip to England. The flight was American Airlines 87, and we were tracking the first leg on FlightAware, which was London to Chicago. Mid-flight, the plane turned and began a descent into Keflavik, Iceland:



They’re still stuck there, of course missing their connecting flight from Chicago to Knoxville. Just found out their next scheduled departure from Keflavik was cancelled. “Time to spare…”

The pilots said the reason for the diversion was the plane “lost its navigational capabilities”. That seems odd to me - wouldn’t planes on transatlantic flights have multiple redundant means of navigation? I only half joked they should have offered the pilots their iPhones to navigate with.

Of course, something may have been lost in translation, but how does this explanation sound to the airline types here?

 

But they were able to navigate directly to Keflavik, Iceland? Does seem odd.

 

The pilot probably simplified his PA for the pax. You need to have almost everything working when crossing the Atlantic.

 

My thought was that conditions permitting, they could have done that visually.

 

Agreed. Their SOP’s might require a certain level of redundancy, which had been compromised. Or 2 systems were giving conflicting information.

Any American Airlines pilots here who might check out this incident?

 

Speculation or info on this particular flight?

 

Does the sister live in Keflavik?

 

I was on a Pan Am flight back from a World Cup in Rio in the 80’s when a couple of hours into the flight-still somewhere over the trackless Amazon, hours after sunset-the pilot announced that we were going back. They had lost their navigation system (no elaboration). He followed up by saying we needn’t worry, they would fly east to the coast and when they saw the lights of the coastal fishing villages they would follow them back to Rio.

I figured that was fine if they actually spotted coastal lights, otherwise we were headed to Africa.

 

For those who haven't flown transports, most of the avionics are DC powered so when you lose a DC Standby Bus you have lost redundancy. Wouldn't lose the ability to navigate, but you'd lose the backups so you aren't going to continue.

 

FB ??

 

I’m actually the one who is stuck in Iceland right now. It’s been a crazy day and a half. A little back story. My wife son and I were flying from London Heathrow to Chicago ORD airport. During the flight my wife noticed that we couldn’t see where our plane was over the ocean on the screen in the back of the chair ahead of her. After she brought that up we felt and saw the plane turn sharply and then start to gain elevation quickly. We heard nothing from the cockpit so I didn’t think anything about it. Around about an hour later someone from the cockpit came in the overhead speaker and said “don’t be alarmed but the navigation system is not working and our radio is out so we can’t communicate with you from here. I had to leave the cockpit and use the flight attendant one. We have had to turn around and are now landing in Iceland.” My wife son and I were alarmed but had confidence in the pilots. We flew at a pretty high elevation for about another hour and then started to descending. I thought that was normal and we were just descending to land. Land we did not….. For the next 45 minutes to an hour we flew below the cloud line with the flaps up on the plane. It was at that point that I started to get a little scared. Eventually my son saw land and pointed it out to us. A few minutes later the same person from the cockpit came on the overhead and said we are about to land and for us not be be alarmed but there would be emergency vehicles at the landing site.
That’s about it. Sorry if it’s confusing at all. I’m super sleep deprived and typing on my iPhone.

 

From the horse’s mouth! Good luck going forward.

 

Not normal but not terribly surprising either. In the plane I fly the FMS is probably the most flakey piece of equipment.

 

Scud running until they could find Iceland

 

Burning fuel to get to landing weight?

 

They can dump.

I have a picture of fuel dumping from 777. Madagascar to Paris, had to divert to Athens for a medical emergency.

 

Not all airliners can. When I flew the 767 we could but it was about 1000# per hour which is nothing. It’s about the same dump rate as the F-15 but the 767 carries about 10x the gas. The airbus I fly now has no dump capability.

 

Yea. SOP now is to not even dump fuel and to just land overweight. We had a minor emergency a few months ago and we had to air return to JFK and landed about 20,000 pounds overweight

 

"Electronics Toggle Or People Swim"?

 

Whew! Seems like they’re finally on their way home!



Fingers crossed.

 

Yeah, but they’re now facing the most dangerous part of their journey. Chicago.

 

Enjoying Iceland on their nickel. Great! Everything has to work with very close tolerances on the" tracks". Sometimes the airspace is so crowded you can't even get Random routes.
And if you did you would not have the ability to accept them. For example, not enough fuel to complete the flight. The track system, especially across the Atlantic is pretty complicated and has stringent requirements.

 

The instance I mentioned was not a US carrier.

 

With the cost of fuel, it’s probably a lot cheaper to do an overweight landing inspection and repairs than dump fuel.

 

Most manufactures have gone to have the airplane inspected versus fuel dumping. Doesn’t really have anything to do with the price of fuel.

 

All transport category aircraft now have to be certified to land at max takeoff weight. The reason for a lower normal landing weight is repetition without the constant need for inspections.

 

Update: one out of 3 just made it home to Knoxville. The other 2 are still stuck in Chicago but will hopefully be able to catch a flight home tomorrow.

 

Think you might be missing a couple digits. Dump rate on the 767 is 2600#/MINUTE. Not 1000#/HOUR.

 

Almost. About 1300 pounds/minute. It uses both center pumps to jettison fuel but it’s 1300 total. Not 1300 per each pump

 

Sorry, I mis-remembered. 1000# a min was what I was thinking; ok so it's 1300. Either way it's not even REMOTELY close enough to make a difference when you are talking about the fuel loads of a widebody.

(Eagle is also ~1k#/min - actually 990 but I was trying to demonstrate a point)

 

How much fuel did you carry?

In the case of the 777 I was on, we started dumping at altitude, so figure 30 minutes. So 30,000 - 39,000 pounds. And in this case, about 8 hours into the flight.

 

Doesn’t that depend on the result of the inspection?

-Skip

 

Shouldn't be an issue unless the overweight landing was a particularly hard landing.

Certification standards are that the airplane must withstand touchdowns up to 600fpm when at, or below, the max landing weight. When above max landing weight, but at or below the max takeoff weight, that is reduced to 360fpm. A 360fpm touchdown is a pretty hard landing.

 

Jettison rate on the 777 is about 5400 pounds per minute with fuel in the center tank. 8 hours into the flight, the center would probably be empty, so rate would be down to 3100 pounds per minute.

 

If you were 8 hours into a flight, the airplane is likely below max landing weight anyway. Not enough info to know for sure without seeing the WDR.

 

Maybe, but you can clearly see the fuel being dumped.

Maybe fuel was enough cheaper in Madagascar to tanker to Paris for the next flight. Dunno.

 

Depends on where we are going, how much cargo/pax we have and what the weather forecast says (just like every other airline flight).

I've never flown the 777 but a quick search turned up this page: https://www.liquisearch.com/boeing_777/specifications

The biggest difference (that I saw) between max T/O and max landing weight was for the 777-200LR which I think was only flown by Delta (before we retired them) in the US. At any rate, that's about 274k# difference if it was max'd out. Another search gave me about 14k#/hr in cruise. We're burning about 28k#/hr in the 330 on takeoff so the 777 must be at least that. Ballpark you'd burn 130k# ish in 8 hours. So you could be overweight by a good bit and need to dump if you were in the worst case configuration and type of 777. Maybe it's worth it to be 30k# lighter? Unless we know more about the specifics it's all a guessing game. They probably had a good reason to dump - and maybe their company says they need to. Could be as simple as that.