Switzwerland's Pilatus and Frances' Daher-Socata, both manufacturers of business turboprop singles, seem to be having trouble defining time frames for producing larger, twin-engine airplanes, respectively dubbed the PC-24 and the NTX. Both designs are still being worked out on but few details have emerged to date.

The PC-24 was to be unveiled in 2012, according to a Pilatus annual report released earlier this year. This has changed, the company told AIN on Tuesday at the EBACE 2012 in Geneva, Switzerland, and now an announcement is to be made at the EBACE 2013 show–in a year.

In any case, the PC-24 is the only civil project Pilatus design engineers currently have on the drawing boards. It is understood to be a twin-engine design but the company would not say whether it is a jet or a turboprop. If financial numbers are any indication of the project’s status, the Swiss firm’s research-and-development spending that jumped from CHF49 million ($52 million) in 2010 to CHF67 million ($72 million) last year, a 37-percent increase, could indicate significant activity.

Meanwhile, Daher-Socata engineers have worked hard to evaluate the defunct Grob SPn business-jet program as a possible basis for a Socata product. The three prototypes are at the airframer’s Tarbes headquarters in France. The first has flown with Socata test pilots, while the second has been used for system tests on the ground. The third, in a disassembled form, has served a production assessment.

Apparently one sticking point has been estimating the cost of certification for a new derivative development. The company’s engineers have performed the bulk of the work, a source close to the project told AIN, while a Daher spokesman said his company is “actively working on the project to meet the economic, market and technical conditions for a program launch.” Therefore, he told AIN, no time frame has been set.

Other options, including a clean-sheet development, remain on the table. This could still be a twin-turboprop. However, according to previous statements, Daher would rather find partners than going it alone.