Electric taxi specialist WheelTug expects its nose wheel drive system to enter service in late 2018.
Chief executive Isaiah Cox tells FlightGlobal that the system developer's certification programme has US Federal Aviation Administration approval to proceed.
The initial certification effort will cover the equipment's installation on Boeing 737NGs.
Cox adds that the certification process will be divided into two sections – one for the drive system and the other for its integration on a particular model – in order to facilitate the supplemental type certificate's adaptation to other aircraft beyond the 737NG.
Several Airbus A320 operators have offered WheelTug use of their aircraft for the certification of a system variant that can be used with the European narrowbody, says Cox.
The supplier wants to provide a version for the A320 family at same point, but no timeline has been set – and Cox says WheelTug might opt to develop the next version for aircraft of another type, such as the 737 Max or a regional jet, before concentrating on A320s.
Neither Boeing nor Airbus is supporting WheelTug's development. Airbus in the past endorsed the joint development by Honeywell and Safran of a main landing gear-based electric drive system. But the two manufacturers abandoned the programme in 2016.
Canadian carrier Air Transat has volunteered to provide a 737-800 for WheelTug's certification effort. Cox says the programme will cover a range of ground and flight tests – for example, to determine that the landing gear operates and retracts normally in spite of the additional weight.
He expects the electric taxi system to deliver the biggest savings for airlines through reducing the time required for tractors to push aircraft back from airport stands. Based on operational data supplied by prospective customers, Cox believes aircraft ready for push-back are often held up by the delays of the ground crew.
As a consequence, airlines allocate more time to the push-back manoeuvre in order to ensure on-schedule departures, he says. While aircraft in the USA need an average of 5.5min for the push-back procedure – before being able to taxi ahead under own power – Cox says WheelTug-equipped aircraft will able to complete that manoeuvre in about 1min.