Owners have long argued that single engine turboprops (SET) have proven sufficiently reliable and safe for IMC operations, but current regulation still does not allow this without a specific derogation. The potential for lower cost, yet still speedy business transport is obvious, so how close is a change in the rules? EBAN asked EASA for the latest status, and took the opinions of the aircraft owners themselves:

Word from EASA

The current applicable regulation is EU-OPS (Regulation (EC) No 1899/2006 of the European Parliament and of the Council of 12 December 2006 amending Council Regulation (EEC) No 3922/91 on the harmonisation of technical requirements and administrative procedures in the field of civil aviation), which does not allow Single Engine under Instrument Meteorological Conditions (SE-IMC) in Commercial Air Transport (CAT). In the meantime, EU Operators may submit a derogation under article 8.3 of EU-OPS for the purpose of being authorised under SE-IMC. Such derogations must be approved by the National Authority and by the Commission.

With the Agency's extension of responsibilities to rule making in the areas of flight crew licensing and air operations, EASA has recently published a Notice of Proposed Amendment (draft rules) for OPS (NPA 2009-02). These draft rules do not yet cover any such provisions either. However, the Agency will launch a rule making task in 2011 (MDM.031) in order to allow SE-IMC operations.

EASA has published on its web site a study about the risk assessment for SE-IMC operations: http://www.easa.europa.eu/ws_prod/r/r_research.php. This study supports SE-IMC operations and recommends a series of risk mitigating measures. The study can be currently used in support of the above derogation requests, and will be used as a basis for the rule making task MDM.031.

The operators' viewpoint

Bruno Budim of Caravan operator BenAir is impatient that most civil aviation authorities and EASA still hesitate to allow commercial operations in IMC and at night although statistical evidence demonstrates higher safety than comparable twin aircraft.

"We are thankful that the Nordic civil aviation authorities in particular for decades have had a pragmatic approach to the subject allowing us to mature and develop operations that are safer and more efficient than with comparable light-twins," he says.

"At a time when general aviation is pressured by economic and environmental constraints unseen before, SET aircraft offer a unique platform to meet tomorrow's challenges: the safety case is very strong and has been made in Europe as well as in the US, Canada and Australia, the economics have proven reliable and viable on many routes where light twins cannot offer a financially-sustainable alternative, and finally the environmental case is by design and by far an unmatched first-in-class."

Should SET operations be successfully integrated into EU-OPS, BenAir believes it will be ideally placed to initiate and develop new projects in areas where it is already active and to support other fellow operators in areas where it is not - be it operationally or geographically.

Says David Fuller, pilot for UK-based Glass Eels Limited: "The CAA's desire to stop SE-IFR is crazy. These aircraft have a wonderful safety record which is only tainted by icing accidents. The fact they have one engine plays no part in the accident statistics."

John Doman, Cessna's vice president of propeller sales is not confident that progress will be made in the short term. "There are solid, statistically proven arguments for the improved safety of a single engine turbine over (for example) older piston twins, but to this stage we (Cessna and other OEM manufacturers of single engine turbine aircraft - Pilatus, Piper, Socata) have not been successful in having EASA take positive action on this issue," he told EBAN. "We formerly had a very proactive and energetic effort from SETA (Single Engine Turbine Alliance) which was composed of the OEMs above, in which we attempted for over 10 years to get this accomplished. It hasn't happened yet and I can't predict when or if it will happen."

But we'll give the final word to Lubomir Cornak of Piper OK as: "If anybody asked me about my Christmas wish regarding the business, I would ask for European regulators to approve the single-engine turbines for IFR commercial operations. This may open new horizons to the whole aviation community and I believe, it would transfer our general aviation from obsolete and underpowered piston twins to modern age of reliable turbine aircraft. Myself being a flight instructor and examiner, I always prefer the single-turbine over two sets of pistons. I am frequently asked if I am not concerned about safety, but the answer is: Safety is the very reason."