* Sydney-London flights require maximum duty time of 23 hours
* Fatigue, pilot experience are issues to discuss - union
* Flights could start in 2022 if business case stacks up
By Jamie Freed
SINGAPORE, May 1 (Reuters) - Qantas Airways Ltd, which hopes to buy planes this year for record-breaking 21-hour flights between Sydney and London has two hurdles left to overcome: getting pilots and Australia's aviation regulator to agree to unprecedented duty times.
Airlines around the world are planning longer flights to compete with one-stop rivals and collect a fare premium of about 20 percent on non-stop routes, which are especially popular with corporate travellers.
Airbus SE and Boeing Co say their aircraft are ready, with only details like seat configuration left to hammer out, Qantas chief executive Alan Joyce said.
But there is a human cost to flying from Sydney to London or New York that must be resolved before tickets are sold, Joyce added.
"We don't have the ability to do that length of duty today so you do need to negotiate that and get the regulator comfortable with it," Joyce told Reuters in a phone interview. "If the business case works ... (we can) put an order in by the end of this year and have aircraft arriving in 2022."
Qantas pilots say the unprecedented length of the new flights means the airline needs do more research, consider more training, use more experienced pilots and change what they say is a flawed fatigue-reporting system.
The maximum pilot duty time on the Sydney-London flights is expected to be around 23 hours, more than the current limit of 20 hours. "Duty" includes time on the ground before and after flights during which the flight crew is working.
Qantas already has 17-hour non-stop journeys between Perth and London with four pilots onboard.
Australia's Civil Aviation Safety Authority (CASA) will evaluate the proposed longer duty time based partly on a study of pilot fatigue on the Perth-London route, agency spokesman Peter Gibson said.
It could approve longer hours, reject the proposal, approve a shorter duty time or require new measures like a more experienced crew or extended rest periods.
"The technological change is obviously there but the human physiological side hasn't changed since the Wright brothers flew," said Mark Sedgwick, the head of the Qantas pilots union, The Australian and International Pilots Association (AIPA). "We really need to understand the effects on human performance on the flight deck of these ultra-long range flights."
The Australian Transport Safety Bureau in January released a study on pilot fatigue that found 60 percent of long-haul pilots had experienced moderate to severe fatigue on their most recent flight.
One issue: take-off times that work best for passengers on long flights are not ideal for easing pilot fatigue.
"From a passenger's point of view, a night flight at the end of the day makes it easier to adjust to the time," former Qantas head of safety Ron Bartsch said. "Obviously being up the front end, (the pilots) are doing some work."
Managing fatigue is a serious issue for airlines globally, and CASA is overseeing a new data-driven fatigue risk-management system at Qantas. The agency says the new system, which also takes into account fatigue reports from pilots, will create a flexible framework for duty times rather than prescriptive rules.
CASA and AIPA are also sponsoring a detailed fatigue study by Monash University that monitors sleep patterns of pilots on the Perth-London route.
Measures to fight fatigue could include putting more flight crew onboard; adding crew beds; requiring more rest before and after flights; providing transport home; and reducing subsequent duty periods, Gibson said.
According to Qantas, pilots who feel too fatigued must complete a report.
The time off is then treated as sick leave, the airline said, but Brad Hodson, a Qantas captain and union official who has flown from Perth to London, said the policy could lead to under-reporting.
"It is easier just to go sick because you don't have to fill in reports," he said.
How pilots are paid when they take time off because of fatigue is an "industrial issue" outside CASA's jurisdiction, Gibson said.
Qantas and AIPA are negotiating a new union contract for long-haul pilots. Joyce said he hoped for an agreement this year.
"AIPA is supportive of the commercial benefits that may flow to Qantas in being able to operate these long premium routes with minimal competition," Sedgwick said. "We want to make sure the safety and fatigue management issues are adequately addressed in the process of enabling these flights."
Crew experience on long-haul flights also will be part of contract negotiations, Sedgwick said.
The world's longest flight is Singapore Airlines Ltd's almost 19-hour journey from Singapore to New York.
Singapore's aviation regulator said in a statement that it requires the airline to have two captains and two first officers on shifts of more than 18 hours, including time before and after takeoff, to "optimise their alertness throughout the flight."
Qantas, which has a maximum duty period of around 20 hours on its Perth-London flights, also has four pilots. Crew can rest in bunks.
But the Australian airline uses one captain, one first officer and two second officers. Second officers are paid less, can fly only at cruising altitudes and cannot take off or land.
Hodson said Qantas did not necessarily need to put two captains and two first officers on each flight. More training for second officers or adding a first officer in place of one second officer were options, he added.
"I think having another qualified pilot who could sit in the seat for take-off and landing would ameliorate a lot of the issues there," Hodson said. "But Qantas won't like that because it costs money."
Joyce said the final crew mix and training had not been decided.
"We will need to work through the safety case and our requirements and then talk to pilots and regulators," he said.
Reporting by Jamie Freed; Editing by Gerry Doyle