The European Union has begun the rulemaking process that could lead to approval of single-engine commercial air transport operations in instrument
meteorological conditions or at night (SE-IMC/night). However, approval is not expected to take effect until the middle of the next decade.

SE-IMC/night is equivalent to operations under U.S. single-engine instrument flight rules. Formal consideration of SE-IMC is a component of the 2009-12 European Aviation Safety Agency (EASA) work program.

EASA says that development of implementing rules (IR) for airworthiness and operational approval for SE-IMC flying is scheduled to begin in early 2011 (assuming budget and resources are available) and should lead to an EASA “opinion” on proposals three years later. Six months after that, guidance materials should appear to support a formal recommendation to the European Commission (EC), although EASA warns that by 2012 priorities may change. (In European legislation, opinions are draft rules sent to the Commission for further process before enactment. New laws are proposed as amendments to the IRs covering a basic regulation; in this case, that covering commercial air transport.)

Under derogation principles that permit member countries to deviate from European Union regulations, several states–including Finland, France, Greece, Norway and Spain–have allowed domestic commercial SE-IMC cargo-only flights by air operator certificate holders under specific conditions. More broadly, the International Civil Aviation Organization also has produced relevant operating standards, but EASA’s predecessor–the Joint Aviation Authorities (JAA)–failed to achieve a consensus among European national aviation authorities during several years of consideration.

Commercial SE-IMC/night flights might have been possible beginning next year had EASA accepted JAA safety data, but the agency’s position was that information included in data from outside Europe did not represent the region’s conditions and circumstances. Last year it said that SE-IMC/night work would require separate rulemaking after its “opinion” on the EASA operations IR next year. A general consensus last year was that SE-IMC/night could be included with other changes in an expected first amendment to EASA operations legislation in 2010 or 2011.

Over the years, various European national aviation authorities have taken contrasting views of commercial SE-IMC/night safety. Some have applied conditions while allowing flights, while others have resisted permitting fare-paying passengers to be exposed to a possible total power loss. In 2007, EASA established an independent assessment “to identify the risks and possible mitigating factors [to assure] that SE-IMC operations do not involve more risks than multi-engine IMC operations.”

Study Defines Risks
The study concluded that fatal SE-IMC/night accident rates from all causes should be “more remote than 4 x 10-6/flight hours”–slightly better than twin-engine safety in comparable categories. Also, fatal SE-IMC/night engine-failure rates should be less than 1.3 x 10-6/flight hours. Recommendations cover aircraft certification testing, training and the need for a copilot.

It also offered a theoretical risk assessment depending on realistic assumptions being made, concluding it was hypothetically possible to show that the target engine-failure/fatal-accident rate was achievable. Permitted operations would have to be subject to “appropriate limitations on cloud ceiling and visibility, [operations] from and to suitable airfields [and on] duration of risk periods when no landing site is within gliding range.”

The EASA rulemaking move is welcomed by Danish operator BenAir Group, whose Norwegian subsidiary operates Cessna Caravan I SE-IMC cargo flights, which is not permitted in Denmark. With Europe’s largest Caravan I fleet, BenAir believes the business, environmental and safety cases for commercial SE-IMC/night operations with single-engine turboprop aircraft have been established.

BenAir sales and business development director Bruno Budim told NBAA Convention News that operators want to serve remote European regions–not metropolitan cities–and that today’s single turbines are much greener and safer than “40-year-old piston twins.”