MUMBAI: In a bid to make
landing at Mumbai airport more accurate, Mumbai International Airport
Pvt Ltd (MIAL) and Airports Authority of India (AAI) are changing the
glides path angle. The glide angle at the main runway (27) is 3.3
degrees now. It will be changed to 3 degrees.
On Tuesday, the
main runway was unavailable for landing and the other end (09) was in
use. Officials said that while work is under way, the glide scope on the
main runway (27) will not be available for the coming two months. This
means, that if visibility drops, all flights would land on the secondary
runway or on the 09 end of the main runway. This may mean a delay of
10-15 minutes.
Airport officials say the glide angle on the main
runway was steeper than globally recommended standards. This means
aircraft descend at a steep angle and at a higher speed. This is now
being changed so that aircraft can land more accurately and at the right
speed. Glide path is an equipment that gives vertical guidance to a
landing aircraft. The aircraft locks the signal and descent angle from
the glide path and starts descending. Its function is to bring the
aircraft to a proper spot or touchdown zone on the runway. Three degrees
is considered optimum.
Though flights at Mumbai airport can land
easily on runway 09, there are no rapid exit taxiways (RET). Hence,
aircraft take 30-50 seconds extra to vacate the runway. Also, low
visibility during winters can hamper flight operations. Officials said
that without the glide path, main runway 27 will be used only when
visibility is at least 2,800 meters. Else, runway 09 or the secondary
runway will have to be used. These two face heavy tail wind conditions
making it tough for big aircraft to land.
"With the glide path,
the minimum required visibility on the main runway is 550m. Without it,
it goes up to 2,800m. During winters, such high visibility is scarcely
possible and landing will have to be moved to the other end of the
runway where tail winds are heavy," said an airport official. "This
means that certain airlines operating long haul flights on bigger
aircraft will have to cut load and fly into Mumbai," he added. Officials
also said that in case visibility drops below 1,800m (the required
minimum for the 09 end and the secondary runway, the airport will have
to be shut. "This, however, is an extreme case scenario," said an
airport official.
An MIAL spokesperson said, "A higher glide
angle has inherent operational disadvantages such as its unsuitability
for Cat-II and Cat-III ILS approaches. MIAL is working jointly with AAI,
Airlines and DGCA on this. Trials of the new flight procedures if
successful will further enhance CSIA's operational efficiency and safety
standards. Also taking all the historical weather pattern into
consideration, the trial period is chosen at the best time of the year
for getting desired results."
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