BAE Systems has won European Aviation Safety Authority (EASA) approval for a significant increase in payload/range for its BAe 146-100/200 regional jet operating from an unpaved runway in Australia.

This approval is now to be sought for other variants of the BAe 146/Avro RJ operating to other unpaved runways in Australia.

The approval follows an innovative two-year project carried out by BAE Systems’ technical specialists working with leading Australian operator Cobham Aviation Services.

The increase could be as much as four tonnes in payload (or up to 40 passengers or extra freight), an additional 700 nautical miles range, or a mix of the two.

The project aim was to increase the number of passengers that can be carried on Cobham routes from Perth in Western Australia using as a trial the unpaved runway at Kambalda, Western Australia and the BAe 146-100.

These routes from Perth are operated to serve the important mining operations across the vast state and so it is vital to carry as many mineworkers as possible into and out of all destinations at any one time.

Ryan Both, Vice President and General Manager Regional Services at Cobham stated: “This approval is great news for Cobham and as a result we’re seeking to carry out further tests at other unpaved runways across Australia using a combination of our BAe 146-100/200s and our newer Avro RJ85 aircraft.

“Being able to operate will full payloads from a range of unpaved runways for our mining resource clients would increase our competitive advantage in a market where we offer something that other operators do not.”

Most variants of the BAe 146/Avro RJ have been certificated for use on unpaved runways and can be supplied with a BAE Systems unpaved runway protection kit that protects the aircraft from potential fuselage damage from runway debris.

But as Stephen Morrison, Head of Flight Operations Support at BAE Systems Regional Aircraft at Prestwick explained, up until now such unpaved runway operations have been payload and range-restricted due to the imposition of a Maximum Take-off Weight (MTOW reduction.
He said: “This reduction was because of an increased structural ‘bump factor’ which was applied to maintain the same factored ground loads as for paved runway loads. Historically in the BAe 146/Avro RJ programme there had only been limited flight testing of operations from unpaved runways with fully instrumented aircraft as market demand had been limited at the time.

“Now with Cobham seeking to fly into and out of more and more unpaved runways, the technical challenge we faced was how to remove this restriction without a dedicated flight test instrumented aircraft. The innovative solution we adopted came from an idea spotted at a BAE Systems Chairman’s Award ceremony where accelerometers had been used to monitor the shipping of missiles.

“We adapted this to place accelerometers at three locations in the airframe of the Cobham BAe 146 flying between Perth and Kambalda to collect data on ‘g’ accelerations at both the paved and unpaved runways. A databank of measurements was collected and a statistical comparison performed for both Perth and Kambalda and this showed no significant difference in paved and unpaved runway operations, so supporting the removal of the ‘bump factor.

“Methodology and substantiation reports had to be prepared for and then verified by an EASA structures specialist and we received approval for this major change in mid-January. Now we have the principles and methodology established, we can work with our operators to get approvals for their unpaved runway operations on a case by case basis.”

The up to four tonnes extra take-off weight now available from unpaved runways means that Cobham can bid for mining flight contracts further afield from Perth; the previous take-off weight penalty meant a fuel stop on the way back to Perth, which is unacceptable to the mining companies. This means greater flexibility in terms of either flying full aircraft non-stop, or a mix of some more passengers and some more fuel to increase range with significantly further afield unpaved runway destinations from Perth now able to be served economically.

There is growing demand for operations from unpaved runways. Older generation jets that have historically been used for these operations are nearing the end of their service lives and the BAe 146/Avro RJ is seen as a right-sized replacement that is fully capable of performing these demanding operations.