Without having a mechanic out on the wing to figure out what the failure is, it's a helluva lot less safe than a fully operational 777.
Unexpectedly losing an engine from an unknown failure which may be ticking seconds to a further systemic collapse is not the same as simply starting off the day without starting an engine.
You seem smart enough to know this...why make such a silly point?
So why is it more safe to fly circles over the Pacific for two hours with the added risk of dumping your full fuel load than it is to fly for two hours overland towards your destination? After the then two hours of completely normal operation, why not press on? The FAA regs allow it. The CAA regs allow it. The Boeing 744 flight manual allows recommends it. Any additional problems would have manifested itself by the third hour. Indeed, if any additional problems developed, they were never in an ETOPS 120-minute situation. They were never more than 60 miles away from a divert airfield on that particular flight route.
Let's be a little practical about this and imagine we are on the flight and in real time.I am assuming several items to describe my thoughts but I have flown across the Atlantic many times to-wards the UK when I also worked for BA (not BAA which stands for British Airports Authority a different company).
Planning: You have a company produced fuel calculation and decide as Captain (or Pilot Flying) to load minimum legal fuel as no adverse conditions expected.
Event: You have an engine surge at a reasonable time after take-off. You have safe altitude and you have no control problems or any items requiring immediate action after recall items of thrust close and autothrottle disengaged. First conscious thought is: We have ample time to consider this. Maintain present altitude is probably decided intuitively.
Decision Process: Here we move into what most pilots have all done intuitively to high degrees but now British Airways and most UK operators are specifically trying to use a decision process that suits the circumstances. In this case with time available almost certainly the Captain and crew would be working to-gether discussing and using available resources.
The NOTECHS behaviour marker system validated under the JARTEL project uses the following for decision-making, as used by BA.
Problem definition and diagnosis:
Hyperthetically: We have an engine surge and the parameters indicate no damage or adverse effects to the aircraft. Discuss with crew members and even draw in relief crew for discussion. Call up maintenance for advice of possibility of any ongoing problems or not. Confirmation and agreement reached that one option is : flight can remain airborne for time being and also well within safe range of many suitable airfields. Suggestion and confirm engine should be shut down rather than increase any risk of damage.
Option generation:
Options: Circle further to consider and ponder, continue en-route for time being, return to nearest suitable airfield such as departure airport, continue to destination. Anything else?
Risk Assessment and Option generation:
Aircraft and passengers and crew are not at risk. All above options safe at present. Which is best ? Which is acceptable? Can fly all of USA over land within safe range of airfields so why not continue en-route for time being and at same time consider options further. Do we have enough fuel for destination if that becomes a viable option? Is it legal and is it acceptable for our company? Etc etc.
Option decided after such deliberations: Continue en-route and buy time in the direction we wish to go and possibly see if destination is achievable, acceptable and viable. Time taken to do this perhaps 20-30 minutes of fuel burn at very heavy weight. Internal thought of Captain
" Is this critical ? I will not know until later in flight but need to carefully watch and consider this." Tell other crew of this thought.
Outcome Review:
Travel a thousand miles and have no adverse problems and all options still available. Fuel burn computer and manual calculations indicates can reach London with legal minimums although have used some contingency fuel. Can contingency fuel be used for such a situation thinks Captain? Yes it can is the agreement of the crew members, and then checked in the ops manual for confirmation as time allows this.
So we now are approaching the Atlantic. Can we proceed legally? Yes
Do company requirement allow us to do this? Yes
Do we have enough anticipated fuel? Yes
Is it completely safe within our acceptable parameters? Yes
Is this an acceptable option to all crew concerned? Yes
Conclusion. Continue to destination London knowing that in any event Shannon in Ireland, ( 90minutes prior to London) Prestwick in Scotland (50 minutes prior to London) Manchester (30 minutes prior to London) and en-route alternatives are still going to be available crossing and approaching landfall the other side of the Atlantic.
En-Route: Fuel monitoring starts to show a poor picture. Poor flight level achieved and cannot improve and cruise fuel burn worse than expected due headwind.
Start the decision process over again:
Problem Definition and diagnosis/ Option generation/ Risk Assessment and Option selection/ Outcome review?
New option selection after the process. We are going to be tight on fuel for London. We may need to select an alternate. Let's go as far as we can which will in any event be well past Ireland before making a final decision but our bottom line is that we shall not go below legal minumum to reach London.
Approaching Scotland realise cannot reach London. Manchester is a likely new destination as we have BA staff coverage at this place. During descent fuel indicates will land with fuel marginally below final reserve fuel. Company requirement is that we must declare a fuel emergency so make a Pan Pan call. ( UK requirements no longer allow crew to request fuel priority descent and landing it's either an emergency or it's not !!!)
Because Pan Pan emergency call made the fire trucks and emergency services have to be in attendance on landing. The media love to report and see this.
Final Outcome Review again:
Was it a safe landing? Yes
Was a decision process used throughout with review? Yes
Were risk factors understood and acted upon ? Yes.
Did the crew exercise Co-operation? Yes
Did the Captain and crew exercise leadership and managerial skills? Yes
Was the captain and crew Situationally Aware in noticing, understanding and projecting ahead changing circumstances? Yes
Did outside influences of wind and altitude allocation affect Captains ongoing decisions? Yes
Did the crew communicate plans and contingencies and bottom lines ahead of events? Yes.