External Sling Load (HESLO)
Sling load flying is one of the most fascinating and technically advanced specialisations in the helicopter world.
This rating enables the pilot to transport suspended external loads and is an essential requirement for those wishing to work as a cargo transport pilot with a helicopter operator.

Air-Evolution Ltd. offers this course with instructors of proven sector experience, conveying the necessary theoretical and practical competencies with professionalism and rigour.
The path to the HESLO rating
Entry requirements
To enrol on the HESLO course, the applicant must hold a completed PPL(H) licence and a valid Type Rating on the helicopter used during training. No additional minimum flight experience beyond that already logged for licence issue is required.
Medical certificate
For this rating, a valid EASA-FCL Medical Certificate is required: Class 2 for PPL(H) holders and Class 1 for CPL(H) holders, issued by an authorised Aeromedical Examiner (AME).
Theoretical training
The 3-hour theoretical programme covers all fundamental aspects of sling load operations: operating limitations, mass and balance calculation with external load, hover out of ground effect (HOGE) performance, vertical reference technique, and use of specialist equipment. A rigorous theoretical preparation is the starting point for safely undertaking the flight sessions.
Vertical reference sessions
The first part of the practical training is dedicated to the vertical reference technique: the pilot learns to manoeuvre the helicopter looking downward through a side window or open door, maintaining precise control of position and attitude. This technique is the foundation of all cargo hook operations and requires high levels of concentration and coordination.
HESLO flight sessions
The second part of the training involves HESLO flight sessions with a load actually attached to the cargo hook. The candidate is trained to manage the take-off, transfer, and placement of the load in various operational configurations, always under the direct supervision of an experienced sling load instructor. The course is conducted on a transport-suitable helicopter, selected according to the specific needs of the candidate.
Final assessment
Upon completion of the 5 hours of practical training, the candidate is assessed by the instructor on the acquisition of the competencies required for safe cargo hook operations. Once obtained, this rating opens the door to professional employment in helicopter cargo transport, one of the most sought-after sectors in the Swiss and international helicopter market.