CARE-ASAS Activity 3: ASM
Autonomous Aircraft OHA
CARE/ASAS Activity 3: ASM workshop
Brétigny, 19 December 2001
Autonomous Aircraft OHA
page 1
Objectives and tasks
 Objectives:

Qualitative assessment of operational hazards related to
Autonomous Aircraft (AA) operations

Identification of “safety-influencing factors”

R&D work, not definitive results
 Tasks:

High-level description of operational procedures and
CNS/ASAS functions based on AA-OSED

Analysis of operational failure scenarios

Consolidation of risk mitigation measures
CARE/ASAS Activity 3: ASM workshop
Brétigny, 19 December 2001
Autonomous Aircraft OHA
page 2
Customised OHA method

Customised OHA method to facilitate identification of factors that
may directly or indirectly impact the Airborne Separation Minima
CARE/ASAS Activity 3: ASM workshop
Brétigny, 19 December 2001
Autonomous Aircraft OHA
page 3
ASAS operations description
Phase
Phase
Title
Conflict status
P0
Traffic surveillance and monitoring
No conflict
P1
Priority determination
P2
Conflict resolution
P3
Conflict monitoring
P4
Conflict resolution negotiation
P5
Abnormal conflict monitoring
P6
Abnormal conflict resolution
Next
phase
P1
Abnormal conflict
Condition
Title
Functions
(air-air) CNS, CD, ASAS
display
C0
Surrounding traffic surveillance and
monitoring
Conflict detected
P0
P0
Conflict
CARE/ASAS Activity 3: ASM workshop
Brétigny, 19 December 2001
Autonomous Aircraft OHA
page 4
Operational failure scenarios
 Failure
conditions related to system functional
characteristics and operational procedures:

Various failure modes either related to system functions or
human operations:

Detected/undetected loss, incorrect/misleading (erroneous
detected/ undetected) function (or information)

Lack of (or inability), incorrect/misleading operation (or human
action)
 Operational
failure scenarios assessment:

Effects on operations, detection and correction means (with
associated (ASS, SR, REC)

Resulting operational consequences (OHs)
CARE/ASAS Activity 3: ASM workshop
Brétigny, 19 December 2001
Autonomous Aircraft OHA
page 5
Operational hazard description
Title of the OH 4 Aircraft not provided with information about surrounding traffic in FFAS
hazard
Hazard
Severity
Description of the operational effects
4
During evolution in FFAS, the aircraft is not
provided with
influencing
information about surrounding traffic (due to loss of ADS-B
reception, ASAS surveillance or traffic displayfactors
capability):
Effects on
flight deck,
air traffic
control and
operations
Safety
1. The flight crew is unable to monitor the surrounding traffic
on CDTI, and thus to continue autonomous operations in
FFAS. If a conflict occurs prior to the failure detection, the
flight crew is not provided with the appropriate information
about conflicting aircraft (Cf. OH 7).
Related
Requirements
P0-F22-1
P0-F4-1
P0,1-F61-1
ASS/ENV 1
The aircraft in emergency situation has to follow the system
failure emergency procedure, and descent in the MAS below
FFAS (Cf. OH 16).
CARE/ASAS Activity 3: ASM workshop
Brétigny, 19 December 2001
P0-F61-2
REC/OPS 1
SR/SYS 6
2. N/A
3. As far as the aircraft is still sending ADS-B reports,
surrounding traffic are able to maintain self-separation from
this aircraft. Therefore, minor impact stands concerning the
safety of the operations in FFAS. Slight increase of workload
may arise for surrounding traffic that have to ensure
separation and give right of way to aircraft in emergency
situation while in FFAS.
Related
Scenarios
SR/SYS 1
Possible cause
with
environmental
factors
ASS/OPS 11
ASS/OPS 9
Autonomous Aircraft OHA
page 6
Identified operational hazards
 During

normal evolution in FFAS:
Aircraft flying in FFAS without or with degraded CNS
capabilities (OH 1 to OH 6)
 During
normal CD&R in FFAS:

Missing, delayed or incorrect CD&R by aircraft that has (or
does not have) priority during conflict in FFAS (OH 7 to OH 12)

Induced conflict by aircraft manoeuvring in FFAS (OH 13,14)
 During

abnormal operations in FFAS:
Multiple OHs in FFAS (OH 15) or during abnormal exit of FFAS
(OH 16,17)
CARE/ASAS Activity 3: ASM workshop
Brétigny, 19 December 2001
Autonomous Aircraft OHA
page 7
Main OSED mitigations (1/2)
 Aircraft
flying in FFAS without RNAV/ASAS
capability:


Segregated FFAS airspace with only suitably equipped aircraft
with qualified flight crew (ASS/ENV 1 )

Including 4D RNAV, ADS-B transmitter/receiver, ASAS based
on ADS-B only, and CDTI equipment

Including priorities rules defining which aircraft in conflict has to
manoeuvre (ASS/OPS 1 )
Emergency procedure in case of an ADS-B/ASAS, or
navigation, system failure (ASS/OPS 9, ASS/OPS 10 )
 Aircraft in emergency situation has right of way over interfering
traffic in FFAS (ASS/OPS 11)
CARE/ASAS Activity 3: ASM workshop
Brétigny, 19 December 2001
Autonomous Aircraft OHA
page 8
Main OSED mitigations (2/2)
 Aircraft
co-operation during CD&R process in
FFAS:


Flight crews’ monitoring of conflict resolution (ASS/OPS 7 ):

Assisted by both aural and visual alarms at TLow minutes before
potential loss of separation (ASS/SYS 1 )

Increasing alarm levels (respectively at TMedium and THigh
minutes) before potential loss of separation (ASS/SYS 2 )
Flight crews’ agreement on a common resolution strategy:

In case of incompatible aircraft priorities during a conflict
(ASS/OPS 3)

If the conflict is not solved TMedium minutes before loss of
separation(ASS/OPS 5 )
CARE/ASAS Activity 3: ASM workshop
Brétigny, 19 December 2001
Autonomous Aircraft OHA
page 9
Additional OHA mitigations (1/3)
 Aircraft
flying in FFAS with degraded ASAS
capability:
Independent ADS-B emission and reception capabilities
(SR/SYS 1)
 To allow the “see or being seen” principle even in case of one
aircraft failure
 Alerting mechanism in case of ASAS system failure (SR/SYS 6)


Additional recommendations even in conflict-free situations:
 Flight crews’ monitoring of surrounding traffic (REC/OPS 1 )
 ASAS alerting when an aircraft in proximity is suddenly no
more detected (REC/SYS 4 )
CARE/ASAS Activity 3: ASM workshop
Brétigny, 19 December 2001
Autonomous Aircraft OHA
page 10
Additional OHA mitigations (2/3)
 Aircraft
flying in FFAS with degraded navigation
capability:

Different separation minima depending on Actual Navigation
Performances (ANP) of the aircraft (SR/ENV 2)

Emergency procedure applied in case of inappropriate ANP
within FFAS (SR/OPS 3)

Alerting mechanism in case of 4D RNAV navigation system
failure (SR/SYS 5)

Display of uncertainty associated with ADS-B traffic position on
CDTI (REC/SYS 5 )
CARE/ASAS Activity 3: ASM workshop
Brétigny, 19 December 2001
Autonomous Aircraft OHA
page 11
Additional OHA mitigations (3/3)
 Potential


loss of separation in FFAS:
At that THigh minutes before potential loss of separation:

Additional rules of flight applicable within FFAS (SR/ENV 1)

Flight crews manoeuvring of their aircraft independently from
their assigned priority using applicable rules of flight in FFAS
(SR/OPS 8)
Based on independent surveillance:
 Alerting mechanism in case of any (imminent) loss of
separation (SR/SYS 7)
 Conflict information to the flight crew in case of (imminent) loss
of separation (SR/SYS 8)
CARE/ASAS Activity 3: ASM workshop
Brétigny, 19 December 2001
Autonomous Aircraft OHA
page 12
Main OHA results
o Mainly related to “airborne
self-separation” inside FFAS
OHs (17) with severity
assignment
&
Safety influencing factors
including
OPS (27), SYS (22), ENV (6)
with
ASS (28), SR (20), REC (7)
o More in-depth analysis of aircraft
system failure scenarios than
human-related errors
CARE/ASAS Activity 3: ASM workshop
Brétigny, 19 December 2001
Autonomous Aircraft OHA
page 13