Plane crash
French and Pakistan investigation team members after completing investigation on the PIA plane crash site in Karachi.

Dubai: It’s been 11 days since Pakistan International Airlines (PIA) Flight PK-8303 crashed in Karachi. But there are questions galore that still remain unanswered. For instance, why did the plane that crashed into a residential area in Karachi on May 22 have an unusual approach on its first landing attempt? What really went wrong with the landing gear and how did both the engines fail?

These are some of the overwhelming questions, which no one has been able to answer so far. Initial investigation hinted at pilot error and at the same time raised questions about the ‘health’ of the aircraft and the ability of the air traffic control (ATC) tower to handle an exigency. 
Here Gulf News looks at some of the key areas and issues related to the crash.

The French team

We hope to get answers once the French investigation team decodes the black box of the plane. The French team flew back on May 31 with the black box components and is expected to start work on it today. The team has already completed its preliminary investigation at the crash site.

An aviation expert associated with the inquiry told Gulf News that human error, coupled with ‘faulty equipment’, might have caused the crash. “There are a few errors that are beyond comprehension to most of us and we hope the French team will be able to arrive at a logical conclusion,” he added on condition of anonymity.

Bewildering questions

There are several bewildering questions around the crash: Why did the pilot approach the landing strip from an unusual altitude and at a more-than-normal speed? Secondly, why did he try to land without having opened the landing gear? And most importantly, why didn’t he declare an emergency and alert the ATC that the landing gear had malfunctioned? Did he forget to deploy the landing gear while he was busy trying to bring the aircraft down to a lower altitude, following a warning from the control tower? Answers are still awaited.

SOPs violated

Initial investigation has revealed that multiple standard operating procedures (SOPs) were violated both, by the cockpit crew of the ill-fated Airbus A320 and the ATC. Apparently, warning signals and alarms in the cockpit of the Airbus A320 were ignored, which eventually led to the disaster.

The aircraft was flying way beyond the standard safe landing speed and altitude while it was as close as just four nautical miles from the landing strip of Karachi Airport and the Aerodrome Controller failed to check and raise an alarm over the non-deployment of the landing gear, which led to a near-disastrous first attempt to land, experts said.

As a result, both the engines of the plane scraped the surface of the runway thrice, which led to the failure of both the engines and eventually the crash. This was reported by Pakistani media as well.

A detailed inquiry based on the decoding of the black boxes, including the Digital Flight Data Recorder (DFDR) and the Cockpit Voice Recorder (CVR), will help determine if the pilot had ignored the warning from the Electronic Ground Proximity Warning System (EGPWS) and the Electronic Centralised Aircraft Monitoring System (ECAM) about problems with the landing gear, if any. Alternatively, the pilot could have simply forgotten to deploy the landing gear!

Landing procedure

As part of landing SOPs, when a plane is within 25 nautical miles from the landing strip, the Civil Aviation Authority (CAA) Approach Radar Control takes over and guides the aircraft along its designated landing path. The pilot lowers the landing gear at five nautical miles and then the Aerodrome Controller asks cockpit crew to confirm if the landing gear is down and locked, as the landing gear must be deployed at this stage.

Control tower warnings

As Flight PK-8303 from Lahore approached Karachi’s Jinnah International Airport on May 22, air-traffic controllers were concerned that it was not descending along the proper path, according to reports in Pakistani media. A controller had cautioned the pilot that the aircraft was still flying too “high” and urged him to adjust the altitude. The pilot, however, ignored the warning. Instead, he told the controller: “We are comfortable. We can make it.” This conversation can be heard according to a recording posted by Karachi’s air-traffic radio on the website.

In the case of PK-8303, the pilot had overruled the warning from the ATC upon landing approach and actually overshot the runway at a more-than-normal speed. The pilot had aligned the aircraft with the Instruments Landing System (ILS) path for landing, though the landing gear was still not open. ILS is a precision runway approach aid based on two radio beams, which together provide pilots with both vertical and horizontal guidance during an approach to landing.

What went wrong

“Did the pilot forget to deploy the landing gear in an intense adjustment of a sharp descent from 15,000 feet at 15 nautical miles, to 1,500 feet at 4 nautical miles,” experts questioned. Only a detailed probe will reveal the exact nature of the problem with the landing gear — whether it was a maintenance issue or simply a human error in deployment of the landing gear. Typically, pilots opt for a ‘go around’ and use other options to overcome problems with landing gear deployment and in worst circumstances they go for belly landing.

Above the normal speed

The jetliner was well above the normal speed as it approached the runway, said Jeffrey Guzzetti, former chief accident investigator for the United States Federal Aviation Administration. The plane was travelling at roughly 250 miles an hour (402kmph), around 1,000 feet above the ground, according to tracking website Flightradar24. That is more than 50mph faster than what is typical for jets like A320, Guzzetti said. “They have too much energy for a normal landing,” he said.

While it is possible that in the chaos and confusion the cockpit crew could have forgotten to lower the landing gear, it is still puzzling, according to Guzzetti and John Cox, an aviation safety consultant who had previously flown the A320 as a US airline pilot.

“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 gear extended,” said Cox.

Why the engines failed

According to sources in the CAA, the plane’s engines first made contact with the ground at the 4,500-feet marker, followed by a second contact at the 5,500-feet marker and a third attempt at the 7,000-feet marker. However, though the engines touched the ground, the aircraft’s belly at no point made contact with the runway.

The pilot decided to lift off the plan after the third contact with the runway. Once the plane lifted off for a ‘go around’, its left engine started emitting smoke and later the right engine too stopped working in the ensuing seven-minute period between the first attempt to land and the crash.

Due to the grazing of engines against the surface of the runway at a very high speed — around 337kmph — hydraulic fluid and oil started leaking out from the pipes of the engines that had scraped the ground.

This resulted in a hydraulic failure as all the hydraulic fluid had leaked out from the ruptured hydraulic pipes at the bottom of the engines. This led to other complications. Both the engines had shut down without oil and the plane went into a glider mode with no thrust. Since both the engines had stopped working, the plane rapidly lost altitude during the second attempt to land and plunged into the residential area of Model Colony barely minutes away from the runway, killing 97 out of the 99 passengers and crew members onboard. Two passengers miraculously survived the crash.

Ram Air Turbine

Just before the crash, the Ram Air Turbine, or the manual gear drop, was deployed to solve the landing gear issue, which are visible in pictures of the ill-fated plane, that also show the damaged engines, reports revealed.

According to initial investigations, the pilot made a decision on his own to take a ‘go around’ after he failed to land the first time. It was only during the ‘go around’ that ATC was informed that landing gear did not deploy.

Second attempt at landing

The pilot was then directed by the ATC to take the aircraft to 3,000 feet, but he managed to reach only 1,800. The ATC again reminded the pilot to climb to 3,000 feet, when the first officer responded, saying: “We are trying”. Experts said this failure to achieve the right altitude indicates that the engines were not responding.

While approaching runway 25 L for the second time, the pilots also took a short distance of 1.5 nautical miles instead of the mandatory seven nautical miles as defined for such a large-sized plane.

The aircraft’s failure to approach the landing path from the stipulated altitude and distance again suggests that the engines did not provide enough thrust and speed for both the functions. The aircraft thereafter tilted and crashed suddenly.

“Sir, we have lost engines,” the pilot is heard saying. Then, 30 seconds later, he said: “Mayday. Mayday. Mayday.” All contacts between the control tower and the cockpit was thereafter lost and the plane crashed.

Key points:

• The plane made a steep descent during the first approach to land.

• The landing gear was not lowered during the first approach.

• The plane’s engines made contact with the runway.

• Pilots decided to lift off and ‘go around’ for a second landing attempt.

• Upon trying to lift off, the aircraft could not attain the right altitude.

• Failure of both the engines upon the second attempt to land.

• The plane plunged on to a residential area well short of the runway.

• No emergency was declared during the first failed landing attempt.

ATC conversation during the first attempt to land:

• Pilot to ATC: Sir, we are comfortable now and we are out of 3,500 for 3,000, established ILS 25L.

• ATC to Pilot: Roger. Turn left heading 180.

• Pilot to ATC: Sir, we are established in ILS 25L.

• ATC to Pilot: You are five miles off?

• Pilot to ATC: Roger.

• ATC to Pilot: Pakistan 8303, cleared to land 25L.

Last conversation before the crash:

Pilot: PK-8303 to approach.

ATC: Ji Sir (yes sir).

Pilot: We are to be turning left?

ATC: Confirmed.

Pilot: We are proceeding direct, we have lost both the engines.

ATC: Confirm you are carrying out a belly landing?

ATC: Runway available to land on 2-5.

Pilot: Roger.

Pilot: Sir, Mayday, Mayday, Mayday.

ATC: Pakistan 8303, Roger Sir, both runways are available to land

Audio cuts off.