Here, the pilot of the flight IGO202 performed what is called a “Go-Around” or a Missed Approach procedure.
As you may be able to understand by the name, a Go-Around procedure is where an arrival aircraft coming for landing on a runway with an intention to land, is not able to OR decides not to, land on that runway in that attempt.
Pilots of an aircraft, usually perform this procedure for the following reasons:
- The pilot is not able to sight the runway clearly enough. This could be due to bad weather, like heavy rain, heavy rain combined with mist, and of course due to fog. In some rare cases I’ve seen Pilots initiating a Go-Around because they were not able to sight the runway properly as they were momentarily blinded due to the rising or setting Sun at the horizon directly in front of the cockpit’s windscreen, thereby causing the pilot to lose focus long enough to create a doubt in their mind whether he/she’ll be able to land the aircraft safely. In a such a situation, as per their training, the Pilots always chose the safer option, i.e. To initiate a Go-Around.
- Another possibility is when they are able to sight the runway, but the runway centre-line is not visible for more than a few 100 metres on the ground level (with or without the centre line lighting). This is called RVR (Runway Visual Range) and every Aircraft has a certified minimum RVR operation permission given by the Aviation Regulatory body. In India, the DGCA (Directorate General of Civil Aviation) grants this permission after inspecting the on-board instruments and visual and navigation aids for each aircraft and testing the pilot’s expertise also. So while coming for the final stage of landing the aircraft, if the RVR suddenly falls below the aircraft’s declared “minima” (Aviation term used for the certified minimum safe RVR for that flight), the Pilots choose to go around and hold/circle at a pre-decided distance and altitude awaiting visibility improvement.
- Even when visibility is fine there are several other factors which may force a flight coming for landing, to Go-Around. One of the major factors here is the Cross-Wind Component (To know more about what is Cross-Wind, CLICK HERE!). In short, if the cross-wind component is too high the pilot would have a very hard time keeping the aircraft aligned with the runway centre-line to ensure a safe landing, because the cross wind will be hitting the whole aircraft’s body (called the Fuselage) from one of the sides and pushing it outwards. This may even cause an unstabilized approach, which may subsequently cause the whole aircraft to skid off the runway altogether.
- Apart from Cross Wind, there’s another troublesome wind related factor that can cause an unstabilized approach. It’s called Wind Shear. Wind Shear or Wind gradient, is a difference in wind speed or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical or horizontal wind shear. (To know more about Wind-Shear CLICK HERE!). Now if this phenomena occurs directly in the descent path of the landing aircraft, then it will be enough to de-stabalize it’s alignment with the runway centre-line, moreover it may also cause the aircraft to suddenly lose a few feet of altitude, as well as suddenly lose or gain speed, much faster than required, thereby causing a “Hard Landing” (To know more about Hard Landing CLICK HERE!)The following is a link to a report on a domestic incidence in Bengaluru back in August 2010, when a Jet Airways flight was safely able to Go-Around even after a hard landing: Jet Airways performs go-around after Hard Landing at Bangalore.Unlike the incidence mentioned above, Hard Landings don’t always end with everything safe and intact. Most of such times, things turn ugly pretty fast and that’s exactly what happened in the Crash of an Antonov AN-12 in Mbuji-Mayi in the Democratic Republic of Congo, Africa back in January, 2006.Following are pics during and after the incidence:The following is the link to the article reporting the details of the incidence in brief: Crash of an Antonov AN-12 in Mbuji-Mayi, Democratic Republic of Congo
- Another reason due to which, an arriving flight may perform a Go-Around, could be when the Runway is not clear, i.e. there is some kind of obstruction in the landing path of the flight on the runway. In this case to avoid collision with such an obstruction, the pilot would obviously chose to go around and await re-clearance by the ATC after they’ve ensured that the runway is clear again and safe for that flight to land. When I say obstruction, it could be of various types:
- A ground vehicle like A Crash Fire Tender or some Operational Vehicle like a Jeep or a Toe-Truck crossing the runway at a wrong time or it’s crossing it mistakenly, thinking it’s just crossing one of the taxiways, while in reality it is crossing the runway itself from one side to the other. This kind of occurrences are not rare at big Airports with all their complex taxiway and service-road networks.
- Even an Aircraft taxiing on the ground can also mistakenly enter the runway or try to cross it, due to getting confused because of the complex taxiway and service-road networks at big Airports. It’s rare but quite possible with pilots coming with their aircraft to such an airport for the first time, or a driver who is new on the job at such an airport.
- Sometimes when the previous landed aircraft has not OR could not vacate the runway well in time, then also the Runway is deemed not clear and the next incoming arrival aircraft is instructed to Go-Around. This reminds me of a funny but unfortunate incident from April, this year where a landing aircraft at East Midlands Airport in Derby, United Kingdom; had its Landing gear fall off moments after it touches down, sending it skidding 380ft along the runway. Thankfully there was no loss of life, but the aircraft got significantly damaged. The following is the news report that covers the details of the incidence:Airplane at East Midlands Airport at Derby, UK; had it’s Landing gear fall off moments after it’s touch down.
- Wild or Stray animals can also suddenly appear on the runway. Yes! You read that right! It’s not uncommon for animals like Foxes, Jackals or Dogs to have a permanent dwelling on airfields, since these places have greenery, nice foliage, birds… and therefore food and sustenance opportunities. At airports having frequent sightings of such animals, the ATC Tower Controller purposefully keeps scanning the Runway during every landing and take-off, till the approaching flight lands safely. Since he/she has a good vantage point and if such animal movement is observed on or very near to the runway, the ATC Tower Controller immediately instructs the pilot to initiate a Go-Around to ensure the flight’s safety. You might be thinking that the animals would run away the moment they see such a big, loud, flying machine fast approaching. But No, in some cases it has been observed that the animal was so dumbstruck by the incoming aircraft that it froze at it’s place and just couldn’t move a step.
- Even a case of “Suspected” Dead Bird on the Runway surface requires a Go-Around to be initiated by the pilot after being informed by the ATC Tower Controller. Since in this case, if the pilot still decides to land, the landing gears, while passing over the dead bird’s carcass, would most certainly lose traction on the runway surface for a few moments, since the aircraft would be coming in with great speed (Upon landing, the aircraft still have a ground speed of about 180-200 Knots i.e. roughly 330-370 km/hr). This sudden loss of traction then may cause the whole aircraft to skid off the Runway. But you may ask, how would the ATC be able to sight a dead bird on such a long runway from such a distance, while sitting up there in the ATC Tower? The answer is Maybe Yes, but mostly not possible, they can’t always spot that! Then how would the ATC Tower Controller know for sure that a dead bird might there be on the Runway? This can be possible when the earlier departing flight which just took off from the same runway few moments before, had reported that while taking off they had (or might have had) a bird strike. So now since the bird strike supposedly happened during the take off, there’s a high possibility the dead bird’s carcass could have fallen on the runway. Based on this possibility it’s deemed safer that the ATC Tower Controller instruct the Pilot of the arriving flight to initiate a Go-Around.
- The last major reason that comes to my mind is – LASER Lights shone towards an airplane’s cockpit, when it’s low enough during it’s final landing stages. Believe me! It’s the most scariest and disorienting thing for the pilots. And it is potentially as much dangerous for the flight as any of the other factors described above. The following picture shows the effect of LASER Light being shone directly towards a flying Aircraft’s cockpit:The pilots always get badly disturbed by this activity done by people at the ground, who are unaware of the consequences. As soon as pilots face such a problem, they may decide to initiate a go-around and while doing that they’d inform the ATC Tower Controller. Here the ATC Tower Controller has been given a clear directive which is mandatory to be followed by order of Ministry of Civil Aviation. He/She has to immediately call local police control room. The police surprisingly gets to action pretty quick to investigate matters of this nature, and just in case if the culprit is caught, it’s a jail-time worthy offence to attempt to obstruct operations of a Civil Aviation flight.
All in all these are the major factors that may cause an arriving flight to Go-Around. There are various other smaller factors that may cause it, but the answer is already too long. I hope this answer also covers the actual reason why the Indigo flight 202 had to perform a Go-Around.
Anyway, the next time you’re in one of such flights where you witness a Go-Around situation, don’t panic. It’s safer that way!