Originally Posted by
AceAirspeed
I was on UA69 ARN-EWR on Dec 8th. I was fully expecting a fuel stop as the flight plan time was showing 9:20 when I checked FlightAware. Was surprised that no one mentioned the possibility at check in or when boarding - although I still expected a last minute diversion based on the headwinds and projected flight time. But it didn't happen. Guess I got lucky as it looks like day before and day after diverted.
The flight was not that full - probably about 1/2 full in Economy as far as I could tell, so maybe they were able to load more fuel??
What most people here don't realize is the vast majority of diversions on the B752 are not done solely because of strong headwinds but rather a function of the forecast weather at the destination being below a threshold requiring an alternate airport.
Take your 9:20 flight time for example; the B752 can handle that. It is on the upper end endurance-wise but definitely doable without stopping. However, if the weather at EWR requires an alternate....you're screwed and stopping for gas somewhere. If it is known that an alternate is required before takeoff, you are notified by the crew before leaving. If the weather deteriorates mid flight, then you're forced to stop en route somewhere.
Simply put, the required fuel over destination (planned landing fuel) has to be artificially increased when an alternate airport is required. For example, let's say on a normal, good weather day we plan to land in EWR with 9.5 (9500 lbs of fuel). Unfortunately, the forecasted ceiling is below 2,000' or visibility less than 3SM, so we need an alternate...let's say ALB. The flight from EWR to ALB takes 2.0 (2000 lbs of fuel). Our new minimum fuel requirement at destination is now 9.5+2.0=11.5 (11,500 lbs of fuel), roughly a 20% increase.
Strong headwinds obviously are the fundamental cause for this to be an issue because of the increased flight times. However, if you actually investigate things further, the forecasted ceiling at the destination is usually the technical reason for the vast number of diversions.
For those that care , hope this helps!