M2 – Effects of UA impact dynamics are reduced
AMC1 Article 11 Annex B. M2 Effects of UA impact dynamics are reduced
CAA ORS9 Decision No. 46
M2 Effects of UA impact dynamics are reduced – Level of integrity
| Criterion | Low | Medium | High |
|---|---|---|---|
| Criterion 1 (Technical Design) |
Not applicable |
M2.C1.M.I |
M2.C1.M.I M2.C1.H.I |
| Criterion 2 (Procedures) |
Not applicable |
M2.C2.M.I | M2.C2.M.I |
| Criterion 3 (Training) | Not applicable | M2.C3.M.I | M2.C3.M.I |
M2 Effects of UA impact dynamics are reduced – Level of assurance
| Criterion | Low | Medium | High |
|---|---|---|---|
| Criterion 1 (Technical Design) |
Not applicable |
M2.C1.M.A | M2.C1.H.A |
| Criterion 2 (Procedures) |
Not applicable |
M2.C2.M.A |
M2.C2.M.A M2.C2.H.A |
| Criterion 3 (Training) | Not applicable | M2.C3.M.A | M2.C3.M.A |
Medium level of robustness
M2.C1.M.I
Criterion 1 – Technical design
(a) Effects of impact dynamics and immediate post-impact hazards, critical area, or the combination thereof, must be reduced such that the risk to uninvolved people is reduced by an approximate 1 order of magnitude (90%).
(b) In case of a failure that may lead to a crash, the UAS must contain all elements required for the activation of the mitigation.
(c) Any failure of the mitigation itself must not adversely affect the safety of the operation.
M2.C2.M.I
Criterion 2 – Procedures
Any equipment used to reduce the effect of the UA impact dynamics must be installed and maintained in accordance with the Designer’s instructions.
M2.C3.M.I
Criterion 3 – Training
(a) When use of the mitigation requires action from the remote crew, then appropriate training must be provided for the remote crew by the operator.
(b) The operator must ensure that the personnel responsible (internal or external) for the installation and maintenance of the mitigation measures are qualified for the task.
M2.C1.M.A
Criterion 1 – Technical design
(a) The Applicant must provide evidence of compliance with the Integrity requirements.
(b) If compliance evidence is provided through simulation, the validity of the target environment used in the simulation must be justified.
M2.C2.M.A
Criterion 2 – Procedures
(a) The installation and maintenance procedures must be developed to a standard or means of compliance acceptable to the CAA.
(b) The adequacy of the procedures must be demonstrated through either of the following methods:
(1) Dedicated flight test.
(2) Simulation, provided that the representativeness of the simulation is proven valid for the intended purpose with positive results.
(c) If (a), (b) and Integrity requirements are complied with through a SAIL mark certificate, the applicant must demonstrate that the procedures developed by the Designer in (a) are followed by the operator.
(d) The Applicant must provide evidence of compliance with the Integrity requirements.
M2.C3.M.A
Criterion 3 – Training
(a) The applicant must have developed a training syllabus which must be competency based.
(b) The operator must provide competency-based, theoretical, and practical training for the remote crew.
(c) Personnel responsible for installation and maintenance of the mitigation measures must have completed relevant training.
(d) The Applicant must provide evidence of compliance with the Integrity requirements.
AMC.M2.C1.M.A
Criterion 1 – Technical design
(a) A UAS with an MTOM less than or equal to 900g and a maximum speed of 19m/s may provide automatic compliance with the requirement.
AMC.M2.C2.M.A
Criterion 2 – Procedures
(b) The following standard may be used to demonstrate compliance with the requirement:
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
Lower robustness level requirements to be complied with:
• M2.C1.M.I
• M2.C2.M.I
• M2.C2.M.A
• M2.C3.M.I
• M2.C3.M.A
Additional requirements to be compiled with:
M2.C1.H.I
Criterion 1 – Technical design
(a) Effects of impact dynamics and immediate post-impact hazards, critical area, or the combination thereof, must be reduced such that the risk to uninvolved people is reduced by an approximate 2 orders of magnitude (99%).
(b) The activation of the mitigation must be automated.
M2.C2.H.I
Criterion 2 – Procedures
No additional requirements.
M2.C3.H.I
Criterion 3 – Training
No additional requirements.
M2.C1.H.A
Criterion 1 – Technical design
The Integrity requirements must be complied with to a standard or means of compliance acceptable to the CAA.
M2.C2.H.A
Criterion 2 – Procedures
(a) The flight tests performed to validate the procedures must cover the entire flight envelope or be demonstrated to be conservative.
(b) If (a) and Integrity requirements are complied with through a SAIL mark certificate, the Applicant must demonstrate that the flight envelope of the intended operation is the same as or contained within the flight envelope considered by the Designer.
M2.C3.H.A
Criterion 3 – Training
No additional requirement.
AMC.M2.C1.H.A
Criterion 1 – Technical design
The following standard may be used to demonstrate compliance with the requirement:
[Standard will be added later]
GM1 Article 11 Annex B. M2 Effects of UA impact dynamics are reduced
CAA ORS9 Decision No. 46
GM.M2
(a) M2 mitigation reduces the effect of ground impact after the control of the operation has been lost. This is achieved either through:
(1) Reducing the probability of lethality of the UA’s impact, e.g. energy, impulse, energy transfer dynamics, etc., and/or,
(2) Reducing the size of the expected critical area as shown in the table below, e.g. with the use of parachutes, autorotation, frangibility, stalling the UA to slow the descent and increase the impact angle, etc.
The applicant should demonstrate a required total amount of reduction in either or both factors.
(b) The base assumption in SORA for UAS impact lethality before M2 mitigation is applied is that most impacts are lethal, with the following exceptions:
(1) Impacts from a glide of the UA with a characteristic dimension less than or equal to 1 m.
(2) Impacts from a slide of the UA with a total kinetic energy less than 290 Joules.
The critical area of impact is as defined in the table below, based on the maximum characteristic of the UA. Depending on whether the mitigation is passive, manually activated or automatically activated, the Applicant should provide correspondingly adequate evidence and procedures for a given level of robustness. Reduction of the inherent critical area of a UA by way of analysis is conducted as part of Step 2 of the SORA process and is not part of the M2 mitigation process.
(c) Critical area for each characteristic dimension:
| Maximum characteristic dimension (m) | 1 | 3 | 8 | 20 | 40 |
|---|---|---|---|---|---|
| Critical area (m2) | 6.5s | 65 | 650 | 6500 | 65,000 |
(d) Applicants demonstrating M2 mitigation by reduction of the critical area should use the above values as a baseline for comparison in their proposed mitigation. The Applicant may show a corrected critical area and matching population density, in which case the custom critical area value should be used as the baseline against which the mitigation is assessed, and the custom population density value should be used as a limitation in the operation.
GM.M2.C1.M.I
Criterion 1 – Technical design
(a) Examples of immediate post-impact hazards include fire or release of high energy parts.
The reduction in risk detailed here is equivalent to a “System Risk Ratio” which requires that the combination of functional performance (i.e. the reduction in risk when the mitigation functions as intended) and reliability (i.e. the probability that the mitigation functions as intended) meets the requirement.
Latest research on UAS impacts estimates injuries using the Abbreviated Injury Scale (AIS) developed for automotive impact tests and test dummies. An impact that has a 30% chance of causing an injury of AIS level 3 or greater is estimated to have a 10% probability of death.
The SORA methodology only considers fatalities and does not provide guidance on the injury levels or thresholds beyond which an injury should be considered as a fatality. Further Guidance on how to evaluate impact severity measurement may be found in the following documents:
-
DOI 10.1007/s10439-017-1921-6 Ranges of Injury risk associated with impact from UAS.
-
ASSURE A4 UAS Ground Collision Severity Evaluation
-
ASSURE A14 UAS Ground Collision Severity Evaluation
(b) This excludes failures of the mitigation.
If the mitigation is the frangibility of the UAS structure, all elements required for the activation of it are inherently contained within the UAS.
No single failure should lead simultaneously to the loss of control of the operation and loss of the effectiveness of the M2 mitigation.
(c) This includes inadvertent activation of the mitigation.
GM.M2.C1.M.A
Criterion 1 – Technical design
(a) Compliance evidence is typically provided through testing, analysis, simulation, inspection, design review or through operational experience.
Although not required to achieve a medium level of robustness, the use of industry standards is encouraged when developing mitigations used to reduce the effect of ground impact, e.g. CEN prEN 4709-001, ASTM F3389/F3389M, ASTM F3322-18.
GM.M2.C2.M.A
Criterion 2 – Procedures
(a) Designer data is found on the SAIL mark certificate.
GM.M2.C1.H.I
Criterion 1 – Technical design
(a) No single failure should lead simultaneously to the loss of control of the operation and loss of the effectiveness of the M2 mitigation.
The applicant may still implement a manual activation function, additional to the automated function.