Showing posts with label Glideslope. Show all posts
Showing posts with label Glideslope. Show all posts

Bengaluru International Airport performs well despite the slow down

At a recently meeting of the infrastructure committee of the Bangalore Chamber of Industry and Commerce we had the opportunity to hear from Mr. Marcel Hungerbuehler about India's second greenfield private airport Bengaluru International Airport (BIA), which opened last May.

Based on his discussions and presentation, I compiled some graphs on airport and air travel performance.

There is little doubt that BIA is suffering the effects of the slowdown. Overall passenger traffic is down 17.3% with domestic traffic crashing by 20.5%. The saving grace has been a 6.68% increase in international passenger traffic.

Click on images for a larger view

Bangalore constitutes about 10% of India's total air passenger traffic. There were some apprehensions that the distant location of the airport has contributed to the crash in regional traffic. The graph shows that Bangalore is generally following the same trends as the rest of India, but the recovery in Bangalore seems to be slightly muted when compared to all India. Compared to this, the buses and trains are running quite full, indicating a switch in travel mode by passengers.


From a peak hour load of over 33 flight movements per hour at the old HAL airport, the new airport is down to a maximum of 23 movements per hour, alleviating fears about immediate runway capacity once the recovery commences. At present BIA is around eight million passengers per year. Sources at the airport inform me that BIAL the consortium operating the airport considers the terminal capacity to be around 12 million passengers per year. Once the traffic crosses 9.6 million, they will consider construction of the second terminal to the east of the current terminal, where the current VIP terminal, staff parking and L&T project office is located.


I am sure passengers in the United States will be envious of the baggage delivery times at BIA. The first bag in on the belt five to service minutes after the aircraft arrives, with Oman Air being the most efficient. International flights take as much as 48 minutes for the last bag to be placed on the belt. The reason for this appears to be the x-ray screen by Indian customs of all international arriving baggage. The two Boeing 747 operators Lufthansa and British Airways have the longest arrival times thanks to the volume of baggage.


BIA has the dubious distinction of being on Forbes' "World's most delayed airports" list. The February data shows a significant improvement with 61% on-time flight performance, and another 21% delayed less than 15 minutes (which is considered on-time) for a total of 82%.


It is clear that the capacity constraints caused by airport infrastructure at other Indian airports and the early morning fog during the winter months of December and January are major causes for the poor performance at BIA. Addressing the infrastructure constraints at Mumbai and Delhi will take time, and out of BIAL's control, but address the early morning fog related delays is within BIAL's control.

BIA must upgrade to Cat II ILS and that will require correction of the steep glideslope by the Airports Authority of India (AAI) who are responsible for the air traffic control and navigation at the airport including the initial faulty installation of the ILS equipment. This will require each side of the runway to be shut down for 25 days.

Sources at the airport tell me that correcting the glideslope has been the top-most priority since the airport opening. The incorrect installation was done by the AAI and now a new hut is required to re-locate the ILS equipment. The sticking point is cost. Naturally BIAL will expect AAI to bear the cost. AAI while agreeing verbally is not issuing a letter to this effect, leaving the corrective actions hanging and passengers suffering.
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Steep glideslope at Bengaluru International Airport contributes to delays and safety concerns

In my previous article I highlighted the faulty glideslope at Bengaluru International Airport (BIA) being a contributor to delays, especially in times of fog. Last Sunday January 24, 2009, BIA, again, experienced significant delays due to fog.

This issue has been hanging fire at Bengaluru International Airport since opening day.

I came across an article by Capt. A. Ranganathan, an Airline Instructor Pilot on Boeing 737 with a flying experience of 20,000 hrs, which explains the situation more technically, and with the right dose of humour.
To err is human but when an error is committed repeatedly, one must credit them with complete incompetence. They have proved that they are champions in “Bending it like Beckham”!

New Greenfield airports are constructed in Bangalore and Hyderabad. The runways are located in areas free of obstacles and the builders install PAPIs (Precision Approach Path Indicators) at a perfect 3° angle. PAPIs are mandatory equipment required by ICAO for airfields where airliner jets operate. These assist pilots to complete a precise landing in the touch down zone after they transition from an instrument approach. All the four runways, two in each city, had these installed at 3° angle.

The AAI installed the ILS (Instrument Landing System) for all the four runways. And they showed why they are great fans of the footballer. They bent the glide slope angles to 3.30° and 3.40°, instead of synchronising them with the 3° PAPIs. With this master-stroke, they killed the two airports from being capable of operating flights in CAT 2 and CAT 3 ILS conditions in fog. The recent diversions from Bangalore and Hyderabad, and the resultant air traffic congestion at Mumbai could have been avoided if the ILS Glide Slope had been less than 3.25° . The airport owners should have insisted on the AAI redoing the glide slopes. Instead, they bend the PAPI angles up to synchronise with the ILS! This is progressive thinking! Airports which should have functioned ‘24 x 365’ hours in a year are restricted to operations ONLY when the visibility is more than 550 metres,

High Glide Slope angles at Hyderabad and Bangalore. Photos: Naverus and Capt. A. Ranganathan

The implications do not stop there. All aircraft have a structural limit for their landing gear. The maximum rate of descent permitted is 600 feet per minute. A glide slope up to 3.25° will ensure a controlled flare and landing within this limit. Any higher angle will require a descent rate of 800 to 900FPM. A positive flare in the correct time is required. Any delay can result in a hard landing or a late touch down. These are a major threat while landing in heavy rain conditions. If the rain condition is accompanied by changing winds, especially tail winds, it becomes a dangerous recipe.
Read the full article here.
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Erroneous glideslope at BIA

Monday June 16 2008

Monica Jha

BANGALORE: Pilots from two airlines (one domestic and one international) have reportedly complained about problems in landing using instrument landing system (ILS) at the Bengaluru International Airport.

The runway (27 orientation, which is being used presently) at the new airport has a 3.4 degree glideslope for an ILS approach while the international standard for the same is 3 degree. The 3 degree glideslope (the angle of descend with respect to horizontal plane) is an acceptable descent profile world over and, therefore, auto pilots are designed for this profile. At BIA, which has a glideslope of more than 3 degrees, auto pilots do not work and pilots need to resort to manual landing, that can cause hard landing at times.

A three-degree glideslope gives a descent of approximately 318 feet per nautical mile (NM) while for a 3.4-degree glideslope, the descent would be about 370 feet per mile which means an aircraft would descend at a higher speed than recommended.

When an aircraft on ILS follows a 3 degree glideslope, passengers do not feel any discomfort but a 3.4 degree glideslope may result in a steep landing causing discomfort to passengers. The operator of BIA, Bangalore International Airport Limited (BIAL), apparently made a mistake in assessing the elevation of glide path location.

On a continuous descent, an aircraft must maintain a height of 50 feet at the threshold of a runway. Due to errors in calculating the elevation this height at BIA was found to be less than 50 feet. So, BIA had to increase the glideslope to maintain a height of 50 feet at the threshold of runway. However, the glideslope for runway when used in 09 orientation is 3 degrees.

To ratify the problem, BIA would need to relocate its glide path antenna further up, an expert from the aviation industry told this website's newspaper. "But, changing the position of glide path antenna at a live airport and a live runway is not possible as landing without ILS for a few days that would be necessitated for calibrations, would be extremely difficult. BIAL can do it when they change from 27 to 09 runway in November," he added.

Source : The New Indian Express
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