AMC No 1 to CS 27.865  Class D (Human External Cargo) for Operations within Europe

1.       Introduction

This additional EASA AMC, used in conjunction with FAA guidance[11] on Human External Cargo (HEC), provides an acceptable means of compliance with CS 27.865 for Human External Cargo (HEC) applications requiring the use of Category A rotorcraft.

This AMC addresses the difference in operational requirements between the USA and Europe and the absence of dedicated material within the FAA AC.

2.       Basic Definition and Intended Use

CS 27.865 classifies external loads as HEC or NHEC, which are defined in AMC No 2 to CS 27.865. Operational rules may, however, require the use of Category A rotorcraft for specific applications, and this AMC clarifies the corresponding considerations for compliance with CS 27.865.

3.       Certification Considerations

For Category A, a one-engine-inoperative/out-of-ground effect (OEI/OGE) hover performance weight, altitude and temperature envelope should be provided in the flight manual. This becomes the maximum envelope that can be used for HEC applications requiring OEI/OGE hover performance.

4.       Compliance Procedures

4.1     The rotorcraft is required to meet the Category A engine isolation specifications of CS­27 Appendix C, and provide an OEI/OGE hover performance data for a jettisonable HEC weight, altitude, and temperature envelope.

(i)      In determining OEI hover performance, dynamic engine failures should be considered. Each hover verification test should begin from a stabilised hover at the maximum OEI hover weight, at the requested in­ground­effect (IGE) or OGE skid or wheel height, and with all engines operating. At this point, the critical engine should be failed and the aircraft should remain in a stabilized hover condition without exceeding any rotor limits or engine limits for the operating engine(s). As with all performance testing, engine power should be limited to minimum specification power.

(ii)     Normal pilot reaction time should be used following the engine failure to maintain the stabilised hover flight condition. When hovering OGE or IGE at maximum OEI hover weight, an engine failure should not result in an altitude loss of more than 10 per cent or 4 feet, whichever is greater, of the altitude established at the time of engine failure. In either case, a sufficient power margin should be available from the operating engine(s) to regain the altitude lost during the dynamic engine failure and to transition to forward flight.

(iii)     Consideration should also be given to the time required to recover or manoeuvre the human external cargo and to transition into forward flight. An example is the time to winch up and bring aboard personnel in hoisting operations or manoeuvre clear of power lines for fixed strop/basket operations. The time necessary to perform such actions may exceed the short duration OEI power ratings. For example, for a helicopter with a 30-second/2-minute rating structure that sustains an engine failure at a height of 40 feet, the time required to re­stabilise in a hover, recover the external load (given the hoist speed limitations), and then transition to forward flight (with minimal altitude loss) would likely exceed 30 seconds and a power reduction into the 2-minute rating would be necessary.

(iv)     The rotorcraft flight manual (RFM) should contain information that describes the expected altitude loss, any special recovery techniques, and the time increment used for recovery of the external load when establishing maximum weights and wheel or skid heights. The OEI hover chart should be placed in the performance section of the RFM or RFM supplement. Allowable altitude extrapolation for the hover data should not exceed 2 000 feet.

4.2     For helicopters that incorporate engine-driven generators, the hoist should remain operational following an engine or generator failure. A hoist should not be powered from a bus that is automatically shed following the loss of an engine or generator. Maximum two­engine generator loads should be established so that when one engine or generator fails, the remaining generator can assume the entire rotorcraft electrical load (including the maximum hoist electrical load) without exceeding approved limitations.

4.3     The external load attachment means and the complex personnel-carrying device should be shown to meet the provisions of CS 27.865(a) for the proposed operating envelope.

4.4     The rotorcraft is required to be equipped for, or otherwise allow, direct intercommunication under any operational conditions among crew members and the HEC. For HEC applications that require the use of Category A rotorcraft, two­way radios or intercoms should be employed.

[Amdt No: 27/2]

[Amdt No: 27/5]

[Amdt No: 27/6]