Race is on among European manufacturers to become first to gain US retrofit approval after German certification

Thielert Aircraft Engines (TAE) has become the first light diesel engine manufacturer to gain approval to retrofit a light aircraft following supplemental type certification (STC) in Germany for its 100kW (135hp) Centurion 1.7, formerly the Thielert 135, for the Cessna 172 Skyhawk series.

The race is now on to become the first manufacturer to gain US approval for a jet-fuel/diesel engine retrofit, as competition intensifies among European diesel engine producers. French producer SMA, unlike TAE, has already won US certification for its larger 170kW SR305-230 diesel engine and is aiming for STCs for the Cessna 182 Skylane and EADS Socata TB20 early next year.

TAE says: "We have European certification for the 1.7 and US approval is planned for next month or early 2003. Then we will pursue validation of the STC for the Cessna 172, then the Piper PA28." Retrofit is priced at €40,000 ($40,000). The German company's main goal is to sell the engine directly to original equipment manufacturers (OEMs), particularly Cessna, Cirrus and New Piper, for installation on new aircraft types. TAE has sold the 1.7 to Diamond Aircraft to power the DA40 TDI and DA42 twin under development.

TAE is developing a 230kW jet- fuel/diesel engine, the Centurion 4.0, and will begin flight tests in the first quarter of next year. "The Centurion 4.0 is targeted at the Cessna 206, Piper Cherokee, Beech Baron and Bonanza," says TAE, adding that the Centurion 4.0 will also be used to power the five-seat, twin-engined High Performance Aircraft, under development.

SMA's 170kW engine has already been selected by Maule and Cirrus to drive their respective M-7 and SR21tdi new light aircraft. The Snecma/EADS/Renault joint venture company is also pursuing the retrofit market and in April established a joint venture called AeroNexx to secure retrofit business in Europe, North America and South America (Flight International, 16-22 April).

Like TAE, SMA is developing a 230kW diesel engine which it says is set to fly early next year on a B-N Group Islander, with certification planned "around 18 months later". SMA also expects a "significant retrofit market" but, like its European competitor, is also chasing new aircraft installations.

"There are around 180,000 aircraft in the 180-300hp [240kW-400kW] range," says the company. "New aircraft produced represent a maximum of 2,000 new aircraft a year at the moment. SMA has already taken orders from OEMs and we are negotiating with Cessna and Piper for new aircraft."

Meanwhile, UK kit aircraft diesel engine manufacturer Wilksch Airmotive has received Popular Flying Association approval for its 90kW WAM-120 engine and has secured a tranche of investment to fund production and assembly of the two-stroke engine. The company has so far clinched over 40 orders for the £10,000 ($14,500) WAM 120, more than half from owners of the Europa kitplane. Wilksch is also developing a £15,000 four-cylinder 120kW diesel engine, the WAM 160.

Source: Flight International