chips presentation on bouchs aeronautical study

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Performance Based Navigation

Assessing Safety in CHIPS

Philip Church, Helios

15th October 2013

Aeronautical Study for

Buochs

Agenda

• Introductions

• Background to study

• Environment

• Approach

• The Procedure

• Hazard Assessment

• Key conclusions

Background

• Requirement for an instrument approach procedure to

Buochs airport (LSZC) driven by main airport operator

Pilatus:

• PC6, PC7MkII/PC9, PC12 and PC21

• Buochs

• a former military aerodrome

• no instrument approach procedures to the aerodrome

• In times of a closed cloud layer, aircraft approaching must:

° perform an ILS approach to the nearby Emmen (LSME) military

airfield

° aborting the approach below clouds

° continuing VFR to Buochs

However, Emmen ILS only active during military hours

Background - justification

• Variability of weather at Buochs means that without an

IAP, operations associated with test flights or the

arrival of aircraft for maintenance are restricted

• Publication will enable instrument approach procedures

to Buochs realising approximately 200 additional

movements per calendar year

• Availability would substantial improve the safety and

minimise the disruption to Pilatus’ business due to

weather

• Pilatus expecting up to 800 instrument approaches per year

• However:

• runway at Buochs not designated an instrument runway

• runway lighting not ICAO Annex 14 compliant

Environment - Existing facilities

• Buochs aerodrome (LSZC) • Visual runway - 07L/25R, 2000m x 40m

• Elevation - 449 m / 1473 ft

• Blind transmissions - 134.125 MHz (TWR OPS)

• All flights need pre-authorisation

• TWR ATC provided. ATC in approach and arrival until transfer to tower either with Emmen APP or DELTA Zurich in the region of RONIX.

• Existing instrument procedures • Only for departure

Environment - Changes introduced

• Lower minima

• Circling minima (3000 ft)

• LPV (630-940 ft)

• LNAC (860-920 ft)

• Instrument approach to fictitious runway

• Requirement for more controlled airspace to protect

aircraft on approach

• Increased ATC coordination – IFR/VFR

• AIP inclusion – new aerodrome responsibilities

• new processes

Environment - IAP Options

• Traditional – straight in approach not possible due to

terrain

• Only RNAV approach possible would be an RNP AR approach

down to RNP 0.18 or less

° no Pilatus aircraft RNP AR certified

• Alternative:

• a Point-in-Space (PinS) approach

• followed by a visual segment to Bouchs

• Missed Approach Point (MAP) over Lake Lucerne (north of LSZC)

avoiding high terrain.

• However:

• current ICAO definition of PinS approach is helicopter only

• implementation would deviate from ICAO criteria

Approach – ICAO requirements

• Under ICAO guidance, an aeronautical study should

then be performed to analyse the risk and prove the

safety of the approach procedure

• Essentially a FOSA – ATM aspects out of scope

• The aeronautical study need to specifically address:

• How the flight procedure is designed and implemented

• Whether the aircraft performance is sufficient for the

requirements of the procedure in normal and non-normal

configurations and

• Whether the flight crew procedures are adequately specified to

ensure acceptable safety both for normal and non-normal

situations.

Approach – Scope of the study

• Study SHOULD NOT undertake a complete review of the

operations

• Study SHOULD analyse :

• Differences introduced through the flight procedure

• The potential impact that these operations may have on

standard cockpit operating procedures in normal and non-

normal situations

• As such the study was a qualitative assessment of

changes to hazards arising from the new operation,

identifying risk and proposing mitigations as

appropriate

Approach – Consistency with ICAO

•A description of problems and objectives;

•Selection of procedures, methods and data sources;

Establishing the context

• Identification of undesired events;

•An analysis of causal factors, severity and likelihood;

•A description of risk;

• Identification of possible mitigating measures;

•An estimation of the effectiveness of mitigating measures;

•Choice of mitigating measures;

HAZID and risk mitigation workshop

•Presentation of results.

Documentation of aeronautical study

results

The procedure - What is PinS?

• Point-in-Space (PinS) approach procedures

• The procedure is to the DH/MAPt to allow subsequent visual flight manoeuvring for approach and landing – the THR may not be aligned with the final approach segment

• Criteria are specified in ICAO PANS-OPS (Doc 8168 Vol II Part IV) and include: • System tolerance limits for GNSS receivers

• Speed limits for final and missed approach segments

• Limits on leg lengths

• Descent gradients:

° Optimum noted as 6.5% (400 ft/NM) up to operationally justified maximum of 13.2% (800 ft/NM)

• Recommended T/Y approach configuration

The procedure -

example

Proceed “Visual”

VFR missed approach

Note speed limits

SBAS required

The procedure - VFR vs Visual

• Proceed VFR: • Requires the pilot to proceed from the

MAPt to the selected Landing area on

the approach chart with no less than

the visibility and ceiling required on

the approach chart

• For flights not terminating at the

selected landing area on the approach

chart, the pilot is required to

proceed from MAPt under the

applicable VFR for ceiling and

visibility required by the air law

• The pilot is responsible for obstacle

and terrain avoidance from MAPt to

the landing site

• A missed approach procedures is not

provided between the MAPt and the

landing site

• The landing site is not required to be

in sight from the MAPt

• Proceed Visual • Requires the pilot to acquire and

maintain visual contact with the FATO

or elements associated with the FATO

such as heliport lighting, precision

approach path indicator (PAPI) at or prior

to the MAPt

• Obstacle and terrain avoidance from the

MAPt to the FATO is the responsibility of

the pilot

• A missed approach procedures is not

provided between the MAPt and the

landing FATO

The procedure – IAP design

A view from the MAPt

The procedure – Airspace requirements

Safety Argument

Hazard Assessment

• A HAZID workshop was held on 19th January 2012 at

Pilatus training centre in Buochs

• Objectives of the HAZID workshop were to:

• Review the accuracy of the operational concept;

• Identify the hazards that existed from the operation by phase

of flight, including:

° associated with hazards;

° existing mitigations or recovery mechanisms (preventing worst

effect).

• Identify the hazard causes, including:

° existing mitigations that would prevent the hazard occurring;

° required new mitigations;

° analysis of the impact of new mitigations.

Hazard Identification

• Hazards were identified on a phase of flight basis

• Enabled a methodical approach to assessment of the

new approach procedure when compared to a standard

instrument approach and the actions that the flight

crew would be expected to make in each instance.

• Note aeronautical study required because:

• the implemented procedure requires differences to ICAO

requirements and

• the assessment is needed to determine whether these design

differences place additional mitigating requirements on flight

operations

Hazard classification

• In accordance with CS AMC 25.1309-25 risk matrix

Severity

CATASTROPHIC HAZARDOUS MAJOR MINOR

Fre

quency

PROBABLE UNACCEPTABLE UNACCEPTABLE UNACCEPTABLE TOLERABLE

REMOTE UNACCEPTABLE UNACCEPTABLE TOLERABLE NEGLIGIBLE

EXTREMELY

REMOTE UNACCEPTABLE TOLERABLE NEGLIGIBLE NEGLIGIBLE

EXTREMELY

IMPROBABLE TOLERABLE NEGLIGIBLE NEGLIGIBLE NEGLIGIBLE

Description of hazard Phase of

Flight

Operational

impact Severity Frequency

Aircraft unable to join the IF Initial Increased

pilot workload Minor Remote

Aircraft off track during the initial segment Initial CFIT Catastrophic Extremely

Improbable

Inability to continue SBAS procedure Intermediate Increased

pilot workload Minor Probable

Inability to continue LNAV procedure Intermediate Increased


Obstacle without vertical clearance Final CFIT Catastrophic Extremely

Improbable

Inability to continue SBAS procedure Final Increased


Inability to continue LNAV procedure Final Increased


Aircraft off track Final CFIT Catastrophic Extremely

Improbable

Aircraft descends below minima Final CFIT Catastrophic Extremely

Improbable

Aircraft descends below track Final Pilot workload Major Remote

Loss of pilot situational awareness during

visual transition

DH/MAPt

Visual

segment

CFIT Catastrophic Extremely

Remote

Hazards Identified

HAZARD #11 - Loss of pilot situational awareness

during visual manoeuvring

• The inability to determine the visual reference points

either from meteorological conditions or due to

familiarity with the terrain in minima conditions

• Flight crew workload in configuring aircraft and

transitioning to visual flight

• Lack of flight crew familiarisation with the environment

to be able to orientate with respect to the terrain

• Changing meteorological conditions between the

DH/MAPt and the runway

• distance to go of approximately 7NM between DH and MAPt

• Flight crew inability to determine meteorological

minima before passing the decision point

• approximately 13 seconds to identify the required VRPs at the

standard approach speed based on a 900ft ceiling

HAZAD #11 – risk mitigation

• No existing mitigations were currently available

• The probability of the CFIT whilst Extremely Remote

needed to be improved to make the hazard tolerable

• Mitigations:

• Aerodrome PPR extension

• Training

• Charting

• Meteorology

• Training deemed most important element and essential

to make hazard ‘Tolerable’

In effect - an authorisation only procedure on the basis of training

being required


• Charting:

• A visual chart should be published as part of the approach chart

would provide the flight crew with guidance for visual part of

the procedure (i.e. clear VRPs define for the decision point)

and additional VRPs for the visual segment

• Charting the approach after the DH/MAPt as a visual segment

would enable the aircraft to remain IFR in the event that the

approach had to be abandoned after the MAPt

• Perhaps different minima based on crew qualifications


• Meteorology

• An additional meteorological observation point (under the

control of Buochs aerodrome) to provide redundancy and

capability to cover more of the visual segment

• Local meteorological conditions can change quickly, and the

lowest minima on the charts should therefore only be available

to flight crew with a familiar local understanding of the

dynamic MET changes

• It was noted that this mitigation would require additional time

and cost – and possibly delay implementation

In conclusion

• Focus on those risks arising from the parts of the

procedure not aligned with ICAO Standards

• A standard aeronautical hazard assessment process,

based on assessment of risk per phase of flight and

analysis of potential causes and mitigations

• Many of the hazards identified, and their basic causes,

were common to existing LPV and LNAV procedures

• Mitigations already had examples in Switzerland:

• Visual approach chart for Sion or the circling approach at Bern

• Operational approval similar to the procedures in Sion and

Lugano

• Recommendation for initial trials with experienced,

local authorised and trained flight crew

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Philip Church

[email protected]

+44 1252 451 668

Thank you for your attention

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