OSO 18 – Automatic protection of the flight envelope from Human Errors
AMC1 Article 11 Annex E. Operational Safety Objective 18
CAA ORS9 Decision No. 46
OSO 18 – Automatic protection of the flight envelope from Human Error
Level of integrity
| Criterion | Low (SAIL 3) | Medium (SAIL 4) | High (SAIL 5, 6) |
|---|---|---|---|
| Criterion | OSO18.L.I |
OSO18.M.I |
OSO18.M.I |
Level of assurance
| Criterion | Low (SAIL 3) | Medium (SAIL 4) | High (SAIL 5, 6) |
|---|---|---|---|
| Criterion | OSO18.L.A |
OSO18.M.A |
OSO18.M.A OSO18.H.A |
Low level of robustness (SAIL 3)
OSO18.L.I
The UAS must include an automatic protection of the flight envelope function which prevents a single input from the remote pilot under normal operating conditions from:
(a) Causing the UA to exceed its flight envelope, or,
(b) Preventing the UA from recovering in a timely fashion.
OSO18.L.A
The Applicant must declare and provide evidence of compliance with the Integrity requirements. The detailed evidence of compliance may be assessed by the CAA.
AMC.OSO18.L.A
The automatic protection of the flight envelope may have been developed in-house or may be a commercial off-the-shelf equipment not designed to any specific standard.
Medium level of robustness (SAIL 4)
Lower robustness level requirements to be complied with:
• None
Additional requirements to be compiled with:
OSO18.M.I
The UAS must include an automatic protection of the flight envelope function which prevents a single or multiple inputs from the remote pilot under any operating conditions from:
(a) Causing the UA to exceed its flight envelope, or,
(b) Preventing the UA from recovering in a timely fashion.
OSO18.M.A
(a) The automatic protection of the flight envelope function must be developed to a standard or means of compliance acceptable to the CAA.
(b) The Applicant must provide evidence of compliance with the Integrity requirements, which will be assessed by the CAA.
AMC.OSO18.M.A
Annex E – AMC 1 Integrity and assurance levels for the Operational Safety Objectives (OSO) paragraph 1.5 provides further information about proposing a standard as an AMC.
High level of robustness (SAIL 5 and 6)
Lower robustness level requirements to be complied with:
• OSO18.M.A
• OSO18.M.I
Additional requirements to be compiled with:
OSO18.H.I
No additional requirements.
OSO18.H.A
The Applicant must provide evidence of compliance with the Integrity requirements, which will be assessed by the CAA. The CAA will validate continuing compliance through oversight.
GM1 Article 11 Annex E. Operational Safety Objective 18
CAA ORS9 Decision No. 46
GM.OSO18
UA are designed with a flight envelope that describes their safe performance limits with regard to minimum and maximum operating speeds and operating structural strength.
Automatic protection of the flight envelope is intended to prevent the remote pilot from operating the UA outside its flight envelope. The Applicant may demonstrate that the remote pilot is not in the loop, in which case OSO 18 is not applicable.
The automatic protection function ensures that the UA is operated within an acceptable flight envelope margin even in the case of incorrect remote-pilot control input (human error).
UAS without automatic protection function are susceptible to incorrect remote-pilot control inputs which may result in the loss of the UA if the performance limits of the aircraft are exceeded.
Failures or development errors of the flight envelope protection function are addressed in OSO 5.
GM.OSO18.L.I
An input from the remote pilot causing the UA to exceed its flight envelope or preventing the UA from recovering from a flight envelope exceedance is considered an erroneous input caused by human error.
GM.OSO18.M.I
The multiple inputs should be considered as happening simultaneously or during the time period when the UA is recovering from the first input.
“Any operating conditions” means that both normal and abnormal (including emergency) operating conditions should be considered.