Safety Issue
Airservices Australia's instrument approach charts did not
depict the terrain contours on the plan-view. They also did not
depict the terrain profile on the profile-view, although the
segment minimum safe altitudes were depicted.
Safety Recommendation
The Australian Transport Safety Bureau recommends that
Airservices Australia address this safety issue.
We [Airservices Australia] are concerned that depicting terrain
contours on the plan and profile of instrument approach charts may
unintentionally create situations that adversely affect flight
safety. One concern we have is that the inclusion of this
information on the plan of the charts will create chart clutter,
making the retrieval of flight critical data from these charts more
difficult, with a possible degradation of flight safety. We are
also concerned that providing pilots with more information than is
required for them to fly the procedure profile could result in
inappropriate use of the information. Instrument approach charts
are designed to be used for instrument approach to the runway. If
pilots fly the procedure profile and adhere to the published
minimum safe altitudes for the various segments of the approach,
aircraft will be protected from the underlying obstacles and
terrain. Deviations below the profile are discouraged by the chart
format with minimum altitude blocks shown below the profile. By
also depicting the terrain contours on the chart profile, we would
not like to create in pilot's minds the false impression that there
is room to descend below the published minimum safe altitudes and
still be protected from terrain. The Australian position in
relation to the depiction of terrain contours on the plan and
profile of instrument approach charts was developed in consultation
with CASA. As the concerns we have in relation to operational
flying and pilot behaviour are not wholly within our competency,
Airservices will consult with CASA to determine the most effective
safety outcome.
Airservices Australia plans to be ICAO complaint with the
terrain requirements for Instrument and Approach Landing (IAL)
charts, by the end of2009. To comply with the ICAO standards, only
six aerodromes have been identified as requiring the inclusion of
terrain. It should be noted that Lockhart River is not included.
Airservices remains committed to partnering with the regulator,
CASA, to further research human factors matters associated with IAL
design and depiction of terrain; as aspects of pilot interpretation
primarily rests with the intent of the regulatory standards that
govern Procedures Design. Airservices is awaiting CASA's direction
in this endeavour.
In relation to recommendation R20070011, the ATSB recognises
Airservices Australia's intention to comply with ICAO Annex 4 as
meeting the intention of the recommendation. However, the ATSB
would appreciate it if you could clarify the reasoning behind the
statement in the Airservices response 'To comply with the ICAO
standards, only six aerodromes have been identified as requiring
the inclusion of terrain. It should be noted that Lockhart River is
not included.' With respect to Lockhart River in particular, this
conclusion appears to be inconsistent with the material presented
on page 154 of the ATSB investigation report into the fatal
accident near Lockhart River (200501977). That stated: The ICAO
Annex 4 Aeronautical Charts stated: 11.7.2 Relief shall be shown in
a manner best suited to the particular elevation characteristics of
the area. In areas where relief exceeds 1 200 m (4 000 ft) above
the aerodrome elevation within the coverage of the chart or 600 m
(2 000 ft) within 11 km (6 NM) of the aerodrome reference point or
when final approach or missed approach procedure gradient is
steeper than optimal due to terrain, all relief exceeding 150 m
(500 ft) above the aerodrome elevation shall be shown by smoothed
contour lines, contour values and layer tints printed in brown.
Appropriate spot elevations, including the highest elevation within
each top contour line, shall also be shown printed in black. ......
The Lockhart River Runway 12 RNAV (GNSS) approach had a final
approach gradient greater than the optimum of 3 degrees, and the
height of both North Pap (1,614 ft) and South Pap (1,453 ft) had
relief higher than 500 ft above the Lockhart River aerodrome which
had an elevation of 77 ft. Before we finalise and close this
recommendation, it would be appreciated if you could confirm which
six aerodromes were identified as requiring the inclusion of
terrain and clarify the rationale for the conclusion that the
Lockhart River RNAV (GNSS) approach to runway 12 does not meet the
intention of Annex 4 as described above.
The ATSB recognises that Airservices Australia has now
redesigned the Lockhart River runway 12 RNAV (GNSS) approach, and
that the new approach chart, to be published in the Aeronautical
Information Publication amendment on 19 November 2009, also
included coloured terrain contour lines on the plan-view diagram
(rather than spot heights only). The ATSB accepts that Airservices
Australia has now met the intention of the safety recommendation
and has closed this safety recommendation - action taken.
As expected and requested, Lockhart River RWY 12 RNAV GNSS
procedure was the first aerodrome to have terrain included onto the
aerodrome plate. This came into effect on 19 November 2009.
Airservices Australia has now completed the remainder of the
Lockhart River approaches, and those for Amberley, Flinders and
Lord Howe Islands. These procedures will be published with an
effective date of 11 March 2010.
Initial progress has been slower than anticipated due to some
cartography technical issues that we have now resolved. As advised
last year, Airservices Australia will continue to work through the
remaining locations on an ongoing basis, and can provide further
updates to the ATSB if requested.
