of airport runway structures matter so much?
dangerous airline accidents can occur during any phase of flight, no doubt
about that but as per the available facts majority of them have taken place during
two phases only, either - the arrival phase or the departure phase. Reason
being, during these phases, aircrafts are close to the ground and are in a more
vulnerable configuration in comparison to the other flight phases. Therefore, frangibility
is a great concern for airports specifically when it comes to considering
various aids –visual and non-visual that are located near taxiways, aprons and
Which airport structures live on
frangibility the most?
For a range of
different mast heights, it is essential to verify the stability and
frangibility of an approach lighting system to ensure that it will perform as
expected in an airport environment. Apart from this, the frangibility and
stability of tall support structures also matter as it has strict allowed deflection
tolerances for lighting, navigational aids and meteorological equipment. Even
though the lighting tower should be strong enough to resist strong wind speeds,
it must be frangible too as most of the frangible structures cannot remain
stable if they are taller and would require non-frangible bases in order to
remain stable. So, frangibility plays an essential role along with stability in
the airport structures.
How frangibility gets ensured in these
Scientifically, a frangible structure should
be designed in such a way that it is able to withstand wind – static and
operational along with jet blast loads with a good factor of safety. However, a
condition that ensures that it should break, distort or yield when subjected to
the sudden collision forces imposed by a 3000-kg aircraft airborne while moving
on the ground at 140 km/h (75 kt) should be fulfilled. There are some more
specific requirements mentioned by the aforesaid bodies while considering
frangibility of airport structures which are as follows –
• Force of the support structure on the
colliding aircraft should not be greater than 45 Kn.
• At the collision, the maximum energy
required to break the mast should not exceed 55 kJ.
• The failure mode of the support structure
should be windowing, bending or fracture so that it can allow the aircraft to
• The impacted structure should offer passage
of the aircraft in such a way that it is able to achieve a less dangerous and successful
missed approach, take-off or landing.
• Designer should ensure the points of disconnection
so that segmentation is not hindered. So, for that the supporting structure and
the light fitting should be considered for establishing frangibility of the
system as a whole along with a consideration to cabling.
• The support structure may fragment into
several components upon impact with a consideration that the mass of these
components should be kept as low as possible with an assurance that their
manner of release should not cause a secondary hazard to the aircraft.
Frangible Airport Solutions by SGS Frangible
Having provided frangible solutions to renowned
airports, SGS Frangible Towers has been at the forefront of meeting ICAO
and FAA requirements. As flying has been one of the safest methods of
transport, it demands a constant vigilance in order to maintain high safety