The Hindu Business Line : Why are we ‘slip slidin’ away’?

Instead of employing ‘ultra-high pressure water hoses’ airports are still using outdated grinding and milling equipment that also takes away some of the top surface, making the runway unsafe.

A. Ranganathan

On December 17, 1978, an Indian Airlines Boeing 737 crashed on take-off at Hyderabad. The aircraft had covered a distance of about 750 metres. A rookie pilot of the same airline commented “Aviation has progressed 500 metres in 75 years”. The date coincided with the 75th anniversary of the Wright Brothers flight, when aviation made its beginning. The first flight on December 17, 1903 had covered about 250 metres!

In one of his hits “Slip slidin’ away”, Paul Simon, of “Simon & Garfunkel” fame, sang:

“God only knows

God makes his plan

The information’s unavailable

To the mortal man

We work our jobs

Collect our pay

Believe were gliding down the highway

When in fact we’re slip slidin’ away”

Has Indian aviation made any progress? Does Indian aviation make any plans? God only knows. God makes his plans and, in India, everybody who is somebody in aviation thinks he is God. How right Paul Simon is when he says: “The information’s unavailable to the mortal man; We work our jobs; collect our pay; believe we are gliding down the runway (to modify the term for aviation)”. And we are “slip sliding away”

The winter rains have started in the north. Foggy days are forecast for Delhi. Contingency plans are in place. Tents have been erected and food-stalls are in place. As it happens every year, the usual noises are made about cancelling permission to operate flights in and out of Delhi unless the airline is CAT-III qualified. Airlines continue to remain CAT-III unqualified and they continue to operate in and out of Delhi. In fact, they are threatening to operate more flights, in spite of lack of infrastructure. God makes his plans!

Flights may land and take off from Delhi. But the poor passengers travelling to and from the less-favoured destinations in the north may have to rely on the Railways. When the rest of the world has moved on to satellite-based navigation with its amazing accuracy, and airlines have spent millions of dollars on state-of-the-art aircraft that can position itself with an accuracy of less than 20 feet, Indian aviation still believes in outdated navigation systems.

Ask the Gods and you will get no answer, or at best a vague answer. Information is unavailable to the mortal man! And we hope to travel safely by air and believe we are gliding down safe runways! This is where we trip.

Friction testing

Ms Delia Harverson and Mr Ian Beaty, two leading experts on runway friction testing, were surprised that, though the friction tester was modern, the test tyres used and what was supplied did not conform to the required standards. It came out that, not just in India, but in several other countries, the wrong test tyres were supplied.

Information available in the form of Annex 14 issued by the International Civil Aviation Organisation, has been overlooked. The standard laid down in the Annex is very specific about what type of tyre can be used. The test tyres have to be smooth and tests can be carried out only when the runway is dry. Ms Harverson gave a detailed presentation on the correct procedure.

Test tyres used in India are grooved. These were supplied by a reputed manufacturer whose recommendations are accepted as correct. Unfortunately, these tyres do not conform to the ICAO standard for maintenance testing. The bombshell that Ms Harverson dropped should make anyone concerned with safety sit up. She said that all runway friction maintenance tests done with “grooved” tyres and any test carried out by non-standard tyres are invalid! She made the statement on November 28, 2007. One hopes that measures are in place to improve the system on a war-footing.

What are the implications of this statement? Are the runways long enough for aircraft operation when the conditions are wet? Should the answer be “God only knows”? We have had several wet runway overruns in India, this year. Human error may be a factor in many of the accidents, or incidents. Should we ignore the fact that correct information on the state of the runway was not given? Should we jeopardise the safety of passengers and aircraft? Or, should we just accept that “information is unavailable to the mortal man”?

Aircraft are certified under two different systems. They are FAR (Federal Aviation Regulations) under the American System and the JAR-OPS (Joint Aviation Authority Operations) system used in Europe. Different regulatory authorities follow either of these systems.

Aircraft manufacturers give out the distances an aircraft requires for landing. These figures have a built-in safety value to cater to the skills of an average pilot, weather conditions, etc. For example, when landing, an aircraft such as the Boeing 737-800, weighing 60,000 kg, would need a stopping distance of approximately 1,000 metres.

As per the rules, an airline has to apply a factor of double this distance before dispatching a flight if the destination runway conditions are wet. Are flights ever cancelled to destinations where the runway length is less than 2,000 metres? Do the regulators insist on this requirement? Especially when we know that the friction testing done on these runways is invalid. And we believe we are gliding down a safe runway!

Runway safety

Are the runway surfaces at their optimum level? The runway is the heart and soul of the airport. But the priority seems to be on other areas. The present methods adopted for surface cleaning are not what a modern airport should be using.

Instead of using equipment such as the ‘ultra-high pressure water hose’, airports are still using outdated grinding and milling equipment that resembles a mosaic polisher! Not only does this remove the rubber deposit only partially, it also removes a certain portion of the top surface. Every time the ‘sophisticated polisher’ is used, the runway becomes smoother and weaker, making it extremely unsafe in rainy conditions.

All jet aircraft leave a fair amount of rubber on the runway surface. Every landing and take-off adds more rubber layers and this builds up in time. This surface, when wet, is not for ‘gliding away’ but for ‘sliding’. The aircraft braking conditions deteriorate from ‘Good’ to ‘Poor” rapidly when the surface is wet and slippery in heavy rain conditions. The factored landing distance of 1.92 times becomes insufficient.

In poor braking conditions on very wet runways, even a test pilot would require more than double the distance. And our cockpits are not manned by test pilots but by ‘ordinary mortals’ — average pilots.

The manufacturers specify what the minimum required distance is but leave it to the operators and the regulatory authorities to decide on what is ‘Safe’.

Will commercial interests play second-fiddle to safety interests in our country? None of the airlines will cancel a flight to a destination because the conditions are bad. Airfields with runway length less than 7,500 feet are really not safe in heavy rain conditions.

Considering that the friction-testing methods adopted are invalid, it makes it dangerous. Airlines should plan their flights based on destination weather affecting runway surface conditions. When the surface is bad, the requirement is a lot more. God only knows!

Winter rains not only bring foggy conditions, they can also make the runways wet and slippery. The monsoons may be six months away. In between, we have the pre-monsoon weather and the “Norwesters” in the Eastern region.

Procuring the correct testing equipment and adopting the latest techniques have to be done immediately. We may have multi-million dollar fire tenders in the airports. It is better to have them on standby than to use them in real situations. We should not let things ‘slip slide away’ and wait for a disaster before waking up.

(The author is an airline pilot with 19,000 hours experience, and specialises in accident-prevention studies.)

More Stories on : Airlines | Accidents | Standards & Benchmarks

Article E-Mail :: Comment :: Syndication :: Printer Friendly Page

Stories in this Section
An auction, it must be

National policy on farmers: Missing out some key issues

Why are we ‘slip slidin’ away’?

India’s dismal record on many fronts

Making Parliament accountable to people

Freedom and security

Selling smart

Wheat inflation