The U.K. Royal Air Force now looks unlikely to receive all four of the Airbus A400M airlifters it had planned on by the end of year.

A series of technical issues and a longer than expected acceptance process for the first of the new transport aircraft, delivered to the main operating base at Brize Norton on Nov. 17 means that delivery of the fourth aircraft, and possibly the third, may now take place early in the new year.

The delivery of the first aircraft MSN15, marked by a ceremony including a visit by Prime Minister David Cameron on Nov. 27 is a major milestone in the introduction of the aircraft into British service.

Since the U.K. swapped a number of production slots with the French government at the beginning of this year, all 22 of the U.K.’s A400Ms will now be delivered by 2018, with officials hoping to establish initial operating capability in 2015 with seven aircraft.

Commanders have a phased plan of introducing new capabilities and missions to the aircraft progressively with tactical capabilities not being introduced until late 2017/18, while full operational capabilities, including flying for Special Forces personnel will be brought in around early 2022 when the C-130J Hercules is currently expected to retire.

All crews will be trained to fly tactical missions down to a height of 250ft., dropping a mix of aerial loads or paratroopers, carry out aerial refueling as well as operating from austere landing strips. An unusual requirement for operations in the Falkland Islands is that crews need to be trained to carry out maritime reconnaissance missions.

A smaller cadre of crews will be trained for specialist flying to support the Special Forces, with high-altitude parachute insertion, the dropping of inflatable boats as well as the conducting of ground-refueling of helicopters and low-flying down to 150ft.

Officers say they are confident that this process will not be hindered by delays experienced by Airbus Defense and Space in delivering tactical capabilities to the aircraft, an issue which has triggered a contract cancellation clause in early November when it went unmet by the company and has proved a sticking point in the negotiations with France, Turkey and Germany. Turkey still has not taken delivery of its second aircraft.

The delays are understood to have added around six months to the introduction of new Standard Operating Clearances. The U.K. aircraft have been delivered with SOC 1, while SOC 1.5, initially expected in the fall of this year, has pushed back into 2015.

“We are progressively building up the capabilities,” explained Air Cdre Stephen Wilcock, the officer heading up the U.K. A400M program. “Our build up is in line with that of the major capability milestones.”

However, the U.K.’s need is not as pressing as other nations, the U.K. can fall back on its still relatively young C-130J and the C-17 fleets, while France, Germany and Turkey continued to struggle on and operating the aging C-160 Transall and older model Hercules.

The arrival of the first British aircraft has not been without issues. Since its arrival in the U.K. on Nov. 17, the aircraft managed to fly one training sortie, before technical problems meant resulted in the aircraft remaining firmly on the ground ever since.

However, crews were hopeful of getting the aircraft back in the air on Nov. 28. Officials said they used the time the aircraft was on the ground to carry out maintenance and other ground training.

The second British aircraft, MSN16 has been delivered to Airbus Defense and Space in Madrid where it is being fitted with its defensive aids suite. The U.K. has gone for a Northrop Grumman-produced directional infra-red countermeasure system common to that already used on the A330 Voyager, the C-17 and the C-130J. A first flight date for the third U.K. aircraft is currently being decided.

On the ground at Brize Norton, a new schoolhouse run by a joint Airbus and Thales consortium called A400M Training Services, features a single full-flight simulator and a flight training device and classrooms with computer-based training aids, is already up and running and is currently teaching a group of instructors as part of Course -1, with Course 0 training the first operational flight crews beginning in January. A second full-flight simulator will follow in 16 along with a high-fidelity cargo hold trainer.

Pilots new to the A400M are being sourced from the C-130J and C-17 communities initially although some ab-initio pilots will follow later downstream. Conversion to type is likely to take around five months, with a mix of ground school, simulator and flying work.

A section of Brize Norton’s main maintenance hangar has been rebuilt and modernized ready for the A400M work, however this is a temporary measure, with new hangarage and maintenance facilities being built on the station ready for when the first A400Ms need depot-level maintenance, around 30 months into the program.

The U.K. is spending £2.8 billion ($4.4 billion) on the introduction of the A400M, which will be known as Atlas in service.