GM1 CAT.POL.H.420 Helicopter operations over a hostile environment located outside a congested area

• ED Decision 2014/015/R found in: Air Operations (965/2012) Part-ARO Part-ORO Part-CAT Part-SPA Part-NCC Part-NCO Part-SPO (Feb 2025)

GM1 CAT.POL.H.420 Helicopter operations over a hostile environment located outside a congested area ED Decision 2014/015/R EXAMPLE OF A SAFETY RISK ASSESSMENT (a) Introduction Where it can be substantiated that helicopter limitations, or other justifiable considerations, preclude the use of appropriate performance, the approval effectively alleviates from compliance with the requirement in [CAT.OP.MPA.137](#_DxCrossRefBm927678512), that requires the availability of surfaces that permit a safe forced landing to be executed. Circumstances where an engine failure will result in a catastrophic event are those defined for a hostile environment: (1) a lack of adequate surfaces to perform a safe landing; (2) the inability to protect the occupants of the helicopter from the elements; or (3) a lack of search and rescue services to provide rescue consistent with the expected survival time in such environment. (b) The elements of the risk assessment The risk assessment process consists of the application of three principles: — a safety target; — a helicopter reliability assessment; and — continuing airworthiness. (1) The safety target The main element of the risk assessment when exposure was initially introduced by the JAA into JAR-OPS 3 (NPA OPS-8), was the assumption that turbine engines in helicopters would have failure rates of about 1:100 000 per flying hour — which would permit (against the agreed safety target of 5 x 10-8 per event) an exposure of about 9 seconds for twin-engined helicopters and 18 seconds for single-engined helicopters during the take-off or landing event. An engine failure in the en-route phase over a hostile environment will inevitably result in a higher risk (in the order of magnitude of 1 x 10-5 per flying hour) to a catastrophic event. The approval to operate with this high risk of endangering the helicopter occupants should, therefore, only be granted against a comparative risk assessment (i.e. compared to other means of transport, the risk is demonstrated to be lower), or where there is no economic justification to replace single-engined helicopters by multi-engined helicopters. (2) The reliability assessment The purpose of the reliability assessment is to ensure that the engine reliability remains at or better than 1 x 10-5. (3) Continuing airworthiness Mitigating procedures consist of a number of elements: (i) the fulfilment of all manufacturers’ safety modifications; (ii) a comprehensive reporting system (both failures and usage data); and (iii) the implementation of a usage monitoring system (UMS). Each of these elements is to ensure that engines, once shown to be sufficiently reliable to meet the safety target, will sustain such reliability (or improve upon it). The monitoring system is felt to be particularly important as it had already been demonstrated that when such systems are in place, it inculcates a more considered approach to operations. In addition, the elimination of ‘hot starts’, prevented by the UMS, itself minimises the incidents of turbine burst failures. GM1 CAT.POL.H.420 Helicopter operations over a hostile environment located outside a congested area ED Decision 2014/015/R EXAMPLE OF A SAFETY RISK ASSESSMENT (a) Introduction Where it can be substantiated that helicopter limitations, or other justifiable considerations, preclude the use of appropriate performance, the approval effectively alleviates from compliance with the requirement in [CAT.OP.MPA.137](#_DxCrossRefBm318086132), that requires the availability of surfaces that permit a safe forced landing to be executed. Circumstances where an engine failure will result in a catastrophic event are those defined for a hostile environment: (1) a lack of adequate surfaces to perform a safe landing; (2) the inability to protect the occupants of the helicopter from the elements; or (3) a lack of search and rescue services to provide rescue consistent with the expected survival time in such environment. (b) The elements of the risk assessment The risk assessment process consists of the application of three principles: — a safety target; — a helicopter reliability assessment; and — continuing airworthiness. (1) The safety target The main element of the risk assessment when exposure was initially introduced by the JAA into JAR-OPS 3 (NPA OPS-8), was the assumption that turbine engines in helicopters would have failure rates of about 1:100 000 per flying hour — which would permit (against the agreed safety target of 5 x 10-8 per event) an exposure of about 9 seconds for twin-engined helicopters and 18 seconds for single-engined helicopters during the take-off or landing event. An engine failure in the en-route phase over a hostile environment will inevitably result in a higher risk (in the order of magnitude of 1 x 10-5 per flying hour) to a catastrophic event. The approval to operate with this high risk of endangering the helicopter occupants should, therefore, only be granted against a comparative risk assessment (i.e. compared to other means of transport, the risk is demonstrated to be lower), or where there is no economic justification to replace single-engined helicopters by multi-engined helicopters. (2) The reliability assessment The purpose of the reliability assessment is to ensure that the engine reliability remains at or better than 1 x 10-5. (3) Continuing airworthiness Mitigating procedures consist of a number of elements: (i) the fulfilment of all manufacturers’ safety modifications; (ii) a comprehensive reporting system (both failures and usage data); and (iii) the implementation of a usage monitoring system (UMS). Each of these elements is to ensure that engines, once shown to be sufficiently reliable to meet the safety target, will sustain such reliability (or improve upon it). The monitoring system is felt to be particularly important as it had already been demonstrated that when such systems are in place, it inculcates a more considered approach to operations. In addition, the elimination of ‘hot starts’, prevented by the UMS, itself minimises the incidents of turbine burst failures. ##### GM1 CAT.POL.H.420 Helicopter operations over a hostile environment located outside a congested area *ED Decision 2014/015/R* **EXAMPLE OF A SAFETY RISK ASSESSMENT** (a) Introduction Where it can be substantiated that helicopter limitations, or other justifiable considerations, preclude the use of appropriate performance, the approval effectively alleviates from compliance with the requirement in [CAT.OP.MPA.137](#_DxCrossRefBm523088067), that requires the availability of surfaces that permit a safe forced landing to be executed. Circumstances where an engine failure will result in a catastrophic event are those defined for a hostile environment: (1) a lack of adequate surfaces to perform a safe landing; (2) the inability to protect the occupants of the helicopter from the elements; or (3) a lack of search and rescue services to provide rescue consistent with the expected survival time in such environment. (b) The elements of the risk assessment The risk assessment process consists of the application of three principles: — a safety target; — a helicopter reliability assessment; and — continuing airworthiness. (1) The safety target The main element of the risk assessment when exposure was initially introduced by the JAA into JAR-OPS 3 (NPA OPS-8), was the assumption that turbine engines in helicopters would have failure rates of about 1:100 000 per flying hour — which would permit (against the agreed safety target of 5 x 10-8 per event) an exposure of about 9 seconds for twin-engined helicopters and 18 seconds for single-engined helicopters during the take-off or landing event. An engine failure in the en-route phase over a hostile environment will inevitably result in a higher risk (in the order of magnitude of 1 x 10-5 per flying hour) to a catastrophic event. The approval to operate with this high risk of endangering the helicopter occupants should, therefore, only be granted against a comparative risk assessment (i.e. compared to other means of transport, the risk is demonstrated to be lower), or where there is no economic justification to replace single-engined helicopters by multi-engined helicopters. (2) The reliability assessment The purpose of the reliability assessment is to ensure that the engine reliability remains at or better than 1 x 10-5. (3) Continuing airworthiness Mitigating procedures consist of a number of elements: (i) the fulfilment of all manufacturers’ safety modifications; (ii) a comprehensive reporting system (both failures and usage data); and (iii) the implementation of a usage monitoring system (UMS). Each of these elements is to ensure that engines, once shown to be sufficiently reliable to meet the safety target, will sustain such reliability (or improve upon it). The monitoring system is felt to be particularly important as it had already been demonstrated that when such systems are in place, it inculcates a more considered approach to operations. In addition, the elimination of ‘hot starts’, prevented by the UMS, itself minimises the incidents of turbine burst failures.