From Friday's SH Independent:
Under the name of the St Helena Government a list of Local
Traffic Regulations was recently published as a supplement
to the Aeronautical Information Publication (AIP) for St Helena
Airport. In the AIP published on 28 th April, 10 days after
Comair’s implementation flight landed, the 11 point section
headed Local Traffic Regulations included one reference to
the wind situation around the airport site; it simply stated,
‘Caution – severe turbulence may be experienced on final
approach.’ Another section of the AIP called Flight Proce-
dures drew attention to the wind shear problem in a two sen-
tence statement which reads ‘Severe turbulence and or wind
shear could be encountered by aircraft conducting Approach
on RWY 02/20, when the wind direction originates from the
south-east quadrant, and in excess of 20 knots at the sur-
face. This turbulence is generally associated with nearby to-
pography to the east of the runway threshold.’
The AIP supplement, published on 23 rd June replaces the origi-
nally published Local Traffic Regulations with a 17 point list of
warnings, procedures, rules and information specific to St
Helena Airport. Point 7 in the Local Traffic Regulations in-
cludes 10 items all of which refer to turbulence, wind shear
and tailwind and the procedures in place to maintain the stand-
ards of safety required at all airports.
Air Traffic Control will issue strong wind warnings to approach-
ing aircraft crew whenever a sustained wind speed of 20 knots
or more is recorded or when gusts reach 28 knots or more.
Wind shear warnings will be issued when the wind speed at
the runway touchdown area is 20 knots and the wind speed
exceeds 40 knots at 2000 feet above the airport or there is
gusting at 35 knots in the airport area. Warnings will also be
issued if a heavy shower is within 10 kilometres of the airport.
Flight crew are asked to pay close attention to the wind direc-
tion indicators (wind socks) located at both ends of the run-
way. It is pointed out, ‘wind shear and/or turbulence may be
experienced below 400 feet above the Runway threshold (at
the northern end). Onset is quick with maximum intensity
immediate’.
Flight crew are warned wind shear can also be present on the
southern final approach to the runway but it is classified as
weak or moderate. Flight crew are also asked to consider
approaching the runway from the south if wind conditions on
the northern approach are too severe. Service messages will
be issued whenever winds exceed 15 knots. St Helena Air
Traffic Control will also report every two minutes the wind speed
to flight crew approaching from the north. Flight crew will also
receive information on the downwind and flight crew can re-
quest ‘instantaneous wind read out, crosswind and tailwind
components’. It is recommended first time operators should
carry out an approach to assess the weather and wind shear
prior to landing.
St Helena’s AIP is published by Air Traffic Navigation Services
- who provide navigation services to South African Airports - in
collaboration with Air Safety Support International – a division
of the UK Civil Aviation Authority concerned with air safety
standards at airports in the British Overseas Territories. Every
airport has to publish an AIP and the layout and content is
Insert
More Wind Related Safety Measures at the Airport
standardised by international agreement through the Interna-
tional Civil Aviation Organisation. Supplements are issued
regularly on fixed dates based on 28 or 56 day cycles de-
pending on whether the information is operationally signifi-
cant or other supporting information. The changes recorded
in AIP supplements are in turn used to update flight manage-
ment systems. These computerised systems perform a wide
variety of in-flight tasks and reduce the workload for flight crews.
Other additional measures to reinforce safety at the airport
may include the installation of a Low Level Wind Shear Alert
System which consists of a network of wind speed measur-
ing devices at ground level positioned near the runway thresh-
old/ touchdown area and along the approach route. Addi-
tional weather radar may help and planes capable of a mak-
ing a steep-angled descent/ take-off are other options which
are probably being considered.
Reaction to the Local Traffic Regulations in the recent AIP
Supplement has been varied. ‘Quite comprehensive’ was one
and ‘the most restrictive set of conditions I have ever seen’
was another. A further comment was comparing these regu-
lations with London City Airport or Madeira and then they don’t
look too bad. The London City Airport regulations include the
runway will be closed when it is wet. Another regulation men-
tions that a missed approach due to wind shear should be
reported to Air Traffic Control. Another comment mentioned
the Avro RJ-85 as a plane which is capable of making a steep
angled decent and thereby avoiding the wind shear without
losing too much runway length. This plane is a regular at
London City Airport. Vince Thompson
Can anyone explain what all this means.