Proponents awaiting European approval for commercial single-engine operations at night or under instrumental meteorological conditions (SE-IMC) should not hold their collective breath. It could be another three years before formal clearance for such
operations–roughly equivalent to U.S. commercial single-engine instrument flight rules–are approved by the European Aviation Safety Agency (EASA).

The issue has proved to be a safety hot potato and was handed over last year by the European Joint Aviation Authorities (JAA), which over several years of discussion and argument had failed to agree on approval before suspending SE-IMC activity with the prospect of responsibility being transferred to EASA.

The safety agency, however, has not automatically accepted data used by the JAA regarding similar operations elsewhere. The International Civil Aviation Organization (ICAO) had already produced commercial SE-IMC operating standards in 2005.

Several individual states–including Australia, Canada, the U.S. and European Union countries such as Denmark, Finland and Norway–have adopted rules that permit commercial SE-IMC operations under specified conditions.

SE-IMC lobbyists had hoped to persuade the JAA to support commercial operations with so-called “risk periods,” of up to a cumulative 15 minutes in any flight.

If accepted by safety officials, the move would have permitted paying customers to be exposed to possible loss of engine thrust while outside the still-air gliding range of undefined alternative landing areas.

The UK Civil Aviation Authority (CAA) was particularly opposed to such a concept, saying it did “not accept the concept of an in-flight ‘risk period.’” Challenged by one SE-IMC advocate about the improvements needed for single-engine safety to be acceptable, the CAA reportedly said it was not tied to “any particular fatal-accident rate” as being a tolerable minimum for operational approval.

Now, EASA has commissioned an independent safety study before proceeding with its own possible proposals for commercial SE-IMC. At best, approval could be granted by early 2010. The study will take into account “all the risks” and is being conducted by UK research contractor Qinetiq, which expects to finish the work by October–possibly opening the way for development of new operating rules to begin later this year or next.

Individual national aviation authorities (NAAs) that until now have dissented from agreement may be consoled by EASA’s rejection of many earlier industry arguments offered in support of commercial SE-IMC clearance. Proponents (including aircraft and engine manufacturers) argued that experience with single-engine operations in other geographical regions provided sufficient data to assure European authorities of SE-IMC safety. SE-IMC advocates included former FAA Administrator Langhorne Bond and Ron Ashford, former director of UK civil-aviation safety regulation and the first JAA secretary-general.

Under JAA procedures, member-country NAAs were free to adopt non-mandatory JAA regulations or apply their own rules to operations with locally registered aircraft in their own airspace. However, when SE-IMC was considered for approval, the innate conservatism of safety officials in states such as Germany, Italy and the UK stymied industry proposals that would have permitted cross-border flights.

Evaluation Under Way

EASA documents inviting tenders for the new safety study pointed out that successive JAA working groups had been involved in preparing draft joint regulations to replace national rules. Myriad proposals were circulated for member states’ comment, but consensus on a draft final rule could not be achieved.

Initially, EASA officials expected to adopt a prospective JAA draft final rule as the basis for the new agency’s own proposal, but lack of consensus and arguments against both a draft final rule and a supporting regulatory impact assessment (RIA) prompted the new research. EASA cites several arguments against SE-IMC and reasons for its review:

•    the concept of “risk periods” on departure and during cruise where there is no available “landing site” provides insufficient safety;

•    specifications for a “landing site” and requirements for its availability and physical inspections are insufficient and do not provide enough safety;

•    operations over densely populated regions might be unacceptable;

•    reliability data on accidents/incidents involving SE-IMC operations are based on non-European (that is, U.S.) data, are considered unbalanced and incomplete, and reflect a prevailing percentage of operations with a single airplane type (Cessna 208 Caravan I) not representative of potential European operations;

•    U.S. data does not reflect specific European conditions, such as population density and lack of suitable landing sites in certain European regions; and
•    composition of the JAA working groups preparing the commercial SE-IMC Notice of Proposed Amendment (NPA) did not balance supporters and opponents.

The safety agency concluded that “at least some” objections–particularly those against the RIA–“might be valid” and suspended planned rulemaking. Instead, EASA will review proposals, based on a “full and objective” risk assessment for each phase of commercial SE-IMC operations: “It is necessary to identify all the risks and possible mitigating factors ensuring that SE-IMC operations do not involve more risks than multi-engine IMC operations.”

In its research, Qinetiq is specifically required to review existing reliability data (using the results of previous JAA work) and particularly to verify that data is “statistically valid, balanced, applicable to the airplanes expected to be used in [European] SE-IMC operations [and] reflects the specifics of the European region.”

Where data does not meet these criteria, EASA permits Qinetiq to identify additional sources to complement and/or update existing information with new data. The contractor also must consider reliability of modern engines, including risk periods and their impact on safety, and the new ICAO requirements adopted into the Annex 6.

If EASA accepts Qinetiq’s conclusions about any inherent risks in commercial SE-IMC operations, the agency then would consult industry through an NPA to its implementing rules on operations. In turn, that could lead to submission of an “opinion” to the European Commission by the end of 2009. Opinions are draft legislation sent to the European Commission for further process by the Commission–or the Council of Ministers and the European Parliament–before enactment. Any new legislation would be an amendment to the EASA Basic Regulation and its implementing rules.