IndiGo A-320 flight from Mumbai to Male nearly landed on a closed under construction runway. The crew realised their error in identifying the wrong runway a few seconds before touchdown & abandoned their landing. In short, the crew had a mental picture of the under-construction runway to the right ,out of the two runways. While the air traffic controllers changed the landing runway direction during descent, the crew did not update their mental image or orientation.

An investigation was ordered by the Indian regulator & the final report was released soon. Read the final investigation report here. The investigator did not look into the human factor of the incident and the thus did not address the root cause. There is little learning from the incident and it can repeat as we have seen the second incident. In the first the aircraft landed on the runway.

Statistics

According to a 2007 Federal Aviation Administration report, there were 267 instances of pilots mistakenly landing on a taxiway parallel to a runway in the United States between 1962 and August 2007. These events, identified through U.S. National Transportation Safety Board and Aviation Safety Reporting System databases, occurred at 110 different airports and involved aircraft from the spectrum of operator types. There were multiple occurrences at 44 of the airports, with single occurrences at the remaining 66. It should be noted that these data included only aircraft that had landed on the taxiway.

Facts leading to bias

This was the first flight operated by either of the operating crew to MALE. The scheduled time of departure from Mumbai-Male(6E-1783) was 0750UTC. The aircraft departed from Mumbai at 0823UTCwith a delay of 33 minutes. Since the crew did not discuss the NOTAM’s at Mumbai, they checked the company Operations Manual–Part ‘C’ in cruise. Since an approach on RWY18 was expected, the First Officer informed the PIC that as per the company Operations Manual-Part ‘C’ among the two parallel runways at MALE the one on the LEFT was the under-construction runway. After establishing contact with MALE(VRMM), the crew received information that active runway at MALE was ILS RWY36and crew planned for the same. During the descent to MALE passing FL110, due to traffic congestion the aircraft was advised to join the HOLD pattern(MM004) as per published STAR. While in the hold the ATC advised that, the ILS RWY36 has become un-serviceable and 6E-1783 was advised to perform a RNAV approach for RWY36, however the crew asked for and performed a VOR36 approach instead.

There was a 15kt wind from the right as a result the aircraft nose was offset to the right, pointing towards the closed runway.

Expectation bias

The Purdue University carried out a study of accidents incidents of landing on wrong runways and wrong airports. One of the reasons for landing at the wrong surface is that flight crew have a mental picture of the airport and orientation of the runways, this is compared with what the pilot see outside. The pilots misjudge the time, speed, distance and; finally,
misidentify the landing surface through distortion of facts of the facts of reality (Antuano & Mohler, 1989). The pilots are thus, disoriented and are inadequately informed by the external visual environment. This is more so when transiting from instrument conditions to visual conditions.

Confirmation bias

Once the human has adopted an opinion either received or self-agreed, he draws all things else to support and agree with it. He then neglects or sets aside and rejects any input even though it may outweigh the current opinion. And though there be a greater number and weight of instances to be found on the other side, yet these it both neglects and despises, or
else by some distinction sets aside and rejects; in order that by this great and pernicious predetermination the authority of its former conclusions may remain inviolate Francis Bacon (1620/1939).

People tend to seek information that they consider supportive of favored hypotheses or existing beliefs and to interpret information in ways that are partial to those hypotheses or beliefs; conversely, they tend not to seek and perhaps even to avoid information that would be considered counter indicative with respect to those hypotheses or beliefs and supportive of alternative possibilities (Koriat, Lichtenstein, & Fischhoff, 1980).

mindFly analysis

The two very important biases discussed above are more commonly triggered when transitioning from an instrument approach to a visual approach and not necessarily from a non-precision approach. In my paper on Inattentional blindness , I have discussed an incident where the crew were aligned to the correct landing runway on an ILS but while transitioning to visual segment, ignored the indications and turned towards the taxiway.

In the IndiGo event, the crew had carried out a brief for an approach for runway 18, the southerly runway. The company document (OMC) which informed the crew about an under construction closed parallel runway at Male was also discussed. The crew therefore had a mental picture that when they see the runway, the landing runway will be to the RIGHT of the under construction runway.

The human mind and the bias had a big role to play. The crew therefore needed to have reprogrammed the mental image that they had planned before descent.

The approach chart, too needs to depict the caution for a closed runway for ready reference.

Whilst the investigator of the incident highlighted issued with the probable cause as the inability of the crew to positively identify the correct runway, the root cause analysis was not carried out. The report fails to provide reasons for the inability of the crew to identify the correct runway. A human factor approach to the incident and in-depth root cause analysis would have addressed the cause(s) rather than just the symptom.

Read my blog on the Haneda, japan incident, which is quite similar.