Firefighters spray water on the wreckage of the Pakistan International Airlines aircraft after it crashed on a residential area in Karachi. Image Credit: AFP

Dubai: While Pakistani politicians are busy hurling abuses at one another for poor response to the Pakistan International Airlines (PIA) plane crash on May 22, investigators are curious to seek answers to the pilot’s bizarre attempt to land the Airbus A320 on its belly, defying all standard safety norms.

Initial investigations revealed that both the engines of the ill-fated PIA plane were damaged as they touched the runway during the pilot’s first attempt to land the aircraft as the landing gear did not open. PIA Flight PK8303 later crashed on to a residential area of Model Colony in Karachi, just short of the runway during its second attempt to land. Ninety-seven of the 99 people on board, including cabin crew members, were killed in the crash on May 22.

What went wrong

A lot of theories and possibilities leading to the crash have emerged. Some say it was the pilot’s mistake, while others raised questions about the poor maintenance of the aircraft. Nevertheless, one thing is sure: The Airbus A320 tried to land without opening the landing gear and its engines had grazed the runway at a speed of 327kmph. A specialised team is investigating the cause of the crash.

Experts have raised questions on how the cockpit crew could try to touch down even though the landing gear had not opened, when the sophisticated jetliner was equipped with technology and equipment to prevent the pilot from doing just that!

Abrupt descent

After an abrupt descent by the aircraft that had unnerved air traffic controllers, the pilots of the PIA jet briefly put the aircraft on the runway without the landing gear, thereby causing the two engines of the plane to graze the ground at a speed of around 327kmph, according to preliminary data cited by Bloomberg.

The pilot aborted the first landing attempt and tried to climb back into the sky. However, shortly thereafter, the engines lost power. The Airbus A320 apparently glided into a dense neighbourhood, even as the pilot was attempting to return to the runway. The plane eventually crashed, killing 97 of the 99 people on board.

“It is unbelievable to me that an airline crew on a jet like an Airbus, with all the warning systems, would attempt to land the plane without the [landing] gear extended,” said John Cox, an aviation safety consultant who formerly flew the A320 as a pilot in the United States.

Safety checklist

In addition to checklists designed to make sure pilots don’t attempt to touch down without the landing gear, the jetliner had multiple warning systems designed to alert crew in case if they forgot to open the landing gear or in case of a malfunction.

It’s not yet clear why the two jet engines stopped functioning for about two minutes to lift the plane about 3,000 feet above the runway. Losing both the engines at the same time is possible only if there is a common factor at work, such as damage from hitting the runway or a problem with the fuel supply.

Bizarre landing attempt

The bizarre landing attempt — which was carried out initially without any indication from the crew that they had met with an emergency — either triggered the accident or was a catalyst that worsened the situation, according to Cox and others who have studied crashes.

A PIA spokesperson declined to comment, citing “incomplete information”.

As Flight 8303 from Lahore approached Karachi’s Jinnah International Airport last Friday afternoon, air traffic controllers were concerned that it wasn’t descending on the proper path, according to reports in Pakistani media. A controller had cautioned the pilot that the aircraft was too “high” and urged him to adjust the altitude. The pilot, however, ignored the warning. “We are comfortable. We can make it,” the pilot could be heard telling the controller, according to a recording of Karachi’s air-traffic radio posted on the LiveATC.net website.

Control Tower warnings

Twice as the plane approached the runway, a controller told the pilot to turn back and break off the approach, according to the report. But the pilot declined to follow the instruction, instead saying he was “comfortable” and was prepared to land on runway 25-Left.

At no point did the cockpit crew say they had a problem with the landing gear or any other type of emergency, according to the radio calls.

Approaching a runway with such a rapid descent, which often leads to higher-than-recommended speeds, is a harbinger of danger, according to decades of warnings from investigative agencies such as the US National Transportation Safety Board and the non-profit Flight Safety Foundation.

After the controllers finally cleared the plane to land — despite their earlier warnings — the pilot replied, “Roger", even as the sound of a cockpit warning chime could be heard in the background.

Above the speed limit

The jetliner was well above the normal speed limit as it neared the runway, said Jeffrey Guzzetti, the former chief accident investigator for the US Federal Aviation Administration. The plane was travelling at roughly 400kmph about 1,000 feet above the ground, according to aircraft tracking website Flightradar24. That is more than 80kmph faster than what is typical for jets like the A320, Guzzetti said. “They had too much energy for a normal landing,” he said.

This more-than-normal speed just before landing not only increases chances of the plane skidding off the runway, but also puts additional pressure on the pilots to slow down the big jet and this can lead to several other things going wrong.

Flightradar24’s data suggest that the jet was travelling at 375kmph when it reached the runway and slowed to about 327kmph as it aborted landing and tried to lifted off. Investigators are yet to validate this data.

According to both Guzzetti and Cox, while it is possible that in the ensuing chaos and confusion the cockpit crew might have forgotten to activate the landing gear, it is still puzzling.

If the landing gear is not out properly as a plane nears the ground, an A320’s on-board computer system issues a warning sound as well as a flashing light to draw the attention of the cockpit crew to a text message. A separate safety system that is designed to prevent the aircraft from inadvertently striking the ground can also sense whether or not the landing gear has been deployed properly before landing. Its pre-recorded voice message issues a warning, repeatedly saying “Too low gear” if the problem persists. A checklist that has to be followed before landing also requires the crew to verify that the plane’s instruments show that the gear is locked into place.

“It’s very unusual in modern transport category aircraft to have a no-gear landing, just because of the checklist and the warnings that go off,” Guzzetti said.

Slammed onto the runway

Around 2.34pm (local time) on May 22, the plane slammed onto the runway. Its engines left a series of black smudge marks, starting at 4,500 feet from the start of the landing strip, according to video footage of the runway broadcast by news outlets. It shows three separate patches, as if the plane had skipped into the air between impacts.

“Going around,” the pilot on the jet told controllers, the term for aborting a landing and lifting off. The plane then climbed to about 3,000 feet, but could not hold its altitude, according to the radio transmission and flight data.

“Sir, we have lost engines,” the pilot said. Thirty seconds later, he said: “Mayday. Mayday. Mayday.”

Removing wreckage

Meanwhile, the process of removing the wreckage of the ill-fated PIA plane has started with the permission of the Airbus investigation team that had arrived in Karachi on Tuesday. The experts have collected crucial evidence from the crash site as well.

PIA posted on its official Twitter account: "Cockpit Voice Recorder (CVR)  has been found from the debris and handed over to AAIB team. This will be a key component in the Air Crash Investigation. PIA Teams were searching extensively for CVR aided by Airbus Team."

Both FDR (Flight Data Recorder) and CVR are key components of the ‘black box’ of an aircraft. In the present case, the CVR is of greater importance as it records all the sounds, including conversations, in the cockpit.