Declaring an Emergency (Mayday)

[CMFlieger]

Having a discussion with another pilot in regards to declaring an emergency in an engine out situation.

Looking for responses from Airline Pilots both Domestic and International. If a flight experiences an engine out in an airliner with two or more engines, is the flight crew required to declare an emergency (Mayday) to ATC or is it pilots discretion depending on company rules or FAA regulations? Is a Pan Pan an acceptable alternative?

Thank you!!

[MarkerInbound]

Required, not really but why not make the call? In a two engine aircraft you're in serious or imminent danger. You're not going to continue the flight. You might even have a different departure route for an engine out that's not your clearance. If you're enroute you're not going to maintain altitude. By saying Mayday, Mayday, Mayday you open up 91.3, 135.19, 121.557 or .559, whatever rules you're operating under. They all say the PIC can do what he thinks is necessary to deal with the situation. In a three or four engine plane it isn't as critical so maybe just Pan Pan but you're still going to slow down or go down or both so you might need some priority handling.

[deltahotel]

Line 10 from 767 QRH for engine failure or shutdown

“10 Declare an emergency and plan to land at the nearest suitable airport.”

[B2N2]

Four engined airplane - Pan Pan call according to our FOM.

[Denti]

Not required by SOPs but considered good practice where i fly. I have flown only twins so far, but seen both Pan Pan and Mayday used in that situation. Pan Pan was never a failing issue, but usually a discussion topic during the debrief.

Personally i would go for mayday: it is recognized everywhere, can be downgraded and gives immediate attention and frees up your workload quite a bit.

[back to Boeing]

From a sim and distant memory of air law. The number 33% sticks in my head. I can’t remember if it’s 33% or more or more than 33% loss of power then a mayday is mandatory. 1 Donk out of 2 mandatory mayday. One Donk out of 4 pan or just continue depending (mayday is also an option, it’s always an option as I found out in China last year when they wouldn’t let us around a particularly nasty cell due to “regulation”)I can’t remember if a dc-10 md-11 or a 727 is a mandatory mayday or not. Hence the 33% or more than 33% confusion