Oct 232015

During the course of your plane journey, your flight passes through many phases and encountered many situations, but as a common passenger, you hardly pay any attention to them, unless there are some significant events. Sometimes, you may wonder about hours of delays at the airport, aborted take-offs, turbulences in the air or a sudden climb of your plane after announcement of landing etc. Some of these events are attributed to the weather, some are due to the safety procedures initiated by The Air Traffic Controllers or by The Pilots. Some situations like Aborted Take-Offs or Go Arounds can really look life threatening, because most of the travellers are not aware of the actual reasons behind such situations. Let us see how scary are those moments and why do they occur suddenly? Knowing the exact reasons behind these events will assure you that Air Travel is very safe.

Go Air Flight

Go Air Flight

1. Why does your flight suddenly stop on the runway after take-off roll? Sometimes, you may find that your flight suddenly stop on the runway after gaining good speed during take-off roll. This event is known as abandoned take-off and may happen due to several reasons. In most of the cases, it happens due to the technical reasons, for example, when a pilot observes malfunctioning of an equipment during take-off roll or observes that a warning light is ON inside the cockpit.

Sometimes, an ATC also instructs a plane to cancel its take-off roll due to the safety reasons, especially when something come on the runway suddenly without any authorization. For example, a plane that was asked to stop before the runway has entered on the runway by mistake, a vehicle or a person entered on the runway or any other issues that may hamper the safety of the departing flight.

How safe is an abandoned take-off depends on the speed of the aircraft during take-off roll. If it aborts its take-off roll at 30-40 knots, it’s very safe, aborted take-off at 60-70 knots is still safe, aborted take-off at 100+ knots has a major risk, because an aircraft can cross the runway end before stopping or can slide into the grass area due to the hard braking and finally, no one wants to abort a take-off roll after reaching the speed of 130-140 knots. It is very-very dangerous. In this case, most of the pilots will pull up in the air, assess their situation and come back to land again.

2. Why do you feel comfortable at the altitude of 35000 feet, where Oxygen density is very rare? Have you ever imagined this? You comfortably cruise at the altitude of 35000 feet sitting in the comfy chairs, but outside atmosphere can be as cold as -50°C to -60°C, with very dry air at very low pressure. Due to some highly advance technical process inside the aircraft , we feel very comfortable inside the aircraft. This technique is known as Cabin Pressurization.

When, because of any reason, the aircraft window cracks, breaks or a leak happens, the plane fails to keep its pressurization. Then, the masks deploy and pilot starts descending to a safe altitude (6000 ft to 8000 ft) where cabin pressurization is not required. The flight crews will continue to fly at that altitude and try to land as soon as possible.

3. Why does your flight start bumping in the air? This is the most common thing occurred during a flight. You happily sip your coffee at 35000 feet and suddenly your flight starts bumping to make you nervous. This is commonly known as Turbulence or more precisely, Clea-Air Turbulence. It mainly happens when a flight enters into an air pocket or clouds, where air currents are flowing at differential speeds.

Normally, every modern aircraft is equipped with a weather radar on-board, but these turbulences are hard to detect, even with radar. The best way to know about these turbulences is by the reports from other flights flying ahead of you at that particular height. Although the vast majority of cases of turbulence are harmless, in rare extreme cases cabin crew and passengers on aircraft have been injured, when tossed around inside an aircraft cabin during extreme turbulence. The best way to encounter a turbulence is to fasten your seat-belt during these conditions.

4. What are the diversions? Sometimes, you don’t able to land at your destination and flight lands at any other nearby airport. This is known as flight diversion.

It happens mainly because of the bad weather at the destination airport or en-route. Sometimes, heavy congestion at destination airport also leads to the flight diversions. Suppose, a flight is coming to Delhi from Mumbai and when it reaches near Delhi, the flight crews find that visibility is very poor in Delhi, or wind is not favourable for landing at Delhi or they find any other problem at Delhi. In such cases, they circle over Delhi for few minutes to wait for weather improvement and if it becomes suitable, they land in Delhi.

If weather doesn’t improve in Delhi for a significant time, and the flight burns out its holding fuel, then, it is supposed to divert to any nearby airport, where they have suitable landing conditions. After landing at another airport, it waits for the weather improvement at the original destination airport and once it improves, it flies down to the destination.

5. Why does your plane start climbing again, after making the landing announcement: This is the most interesting and most scary incident for a normal passenger. When a plane doesn’t land on the runway and starts climbing again, that situation is known Go Around or Missed Approach. Since, every body thinks that they are going to touch the runway very soon, this sudden climb prompt some type of fears in their mind. However, a Go Around is a completely safe procedure for a pilot or for an Air Traffic Controller.

Probable reasons behind a Go Around procedure are:

i). Pilot is unable to maintain the descend profile of the aircraft: Every aircraft is suppose to follow the landing procedures precisely, so that it can touch smoothly on the runway. Sometimes, the aircraft don’t able to maintain their descend profile, so they Go Round to attempt another landing.

ii). Pilot gets warning light in the cockpit: A red button ( I mean an Alarm) can activate anytime during a flight. Sometimes, a pilot may initiate a missed approach, if he gets some sort of warning in the cockpit.

iii). Runway is not clear: Sometimes, Runway gets obstructed due to some unavoidable reasons. In that case, ATC doesn’t issue landing clearance and advises arriving aircraft to carry out missed approach procedure. Probable situations are:
a). A plane enters on the runway by mistake,
b). A vehicle or a person enters on the runway,
c). Bird strike occurs with previous landing/departing aircraft and ATC wants to carry out runway inspection,
d). A preceding departure is not able to depart in time, and runway is not vacant for the arriving aircraft,
e). A previous landing aircraft slows down on the runway and unable to vacate it in time.

iv). Bad Weather: Weather conditions also play a crucial role during landing, especially the wind and the visibility. If the flight crews don’t sight runway/runway lights upto a certain point or some sort of wind shear unstabilized the flight during final approach, they execute missed approach procedure.

So, How scary are the missed approaches? Not at all. They are executed in the interest of safety. It is just like pulling the aircraft again in the air and come back for another landing attempt.

6. How bad are the emergencies? It depends on the nature of emergencies. There are different established procedures to deal with these emergencies like Bomb in a flight, hijack of a flight, engine failure of a flight, hydraulic failure, fuel shortage etc. They need immediate attention, have own associated risks and everybody deals them with utmost attention.

An emergency is always an emergency for Air Traffic Control units, Flight Crews, Fire staffs etc. Everybody has a significant role during these situations. Some emergency situations like a sick passenger in a flight, minor equipment failure etc don’t need the highest priority and flight can safely land in that situations. Sometimes, emergency procedures are activated only as a precautionary measure and flight doesn’t encounter any problem at all.

7. Do you always fly under radar surveillance and ATC communication? Not necessarily. It’s a misconception that flight is always in constant touch with Air Traffic Controllers or constantly watched on radar. Air Traffic Controllers have limited radar coverage, and there are some places (e.g., high sea areas), where they are not able to track your flight in real-time, neither on the voice communication channels nor on the radars. They use High-Frequency channels/Satellite Data Links to communicate with the flight over high seas, but there can be a radio silence of few minutes, because flying at the cruise level is typically uneventful.

8. Is Mid-Air collision possible in the air? Probably not in India. In India, every aircraft has to be equipped with an airborne collision avoidance system ( ACAS). In extreme cases, some aircraft may fly without it, but it happens very rarely. So, when, due to some error caused by ATC or Pilot, two flights come closer to each other in the air, this system generates an alarm to alert the flight crews. If pilot or controller doesn’t able to rectify the problem , and flights come more closer, the ACAS system of both flights automatically communicate with each other and generate another alert to the flight crews. The flight crews respond immediately on this alert without the intervention of an ATC.

These are some common situations, that you can encounter anytime during a flight journey. Some of these situations may make you nervous, but, I hope, you are now able to understand the reasons behind them. These situations are not always as much complicated as they appear, and many times, they occur only because of the normal procedures followed by the pilot and the ATC in their routine job. Air Travel is still the safest mode of transportation. Next time, while facing such situations, just Keep Calm and Trust them. They will handle all situations to keep you safe in the flight. 🙂

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