THREAD
My qualifications: an aeronautical engineering degree from CAE NUST, PAF Academy Risalpur
First of all, let me say that obviously the independent and very capable Safety Investigation Board (SIB)

#PIACrash #PIA #Karachi #Planecrash #PakistanPlaneCrash #PIAPlaneCrash

will conduct a thorough investigation of what actually went wrong, it’s technical aspects, which exact organisation is to blame and what reforms and policy changes are need, whereas I myself will just dabble with the facts and present them to you as I see them.

We, are just going to look at the basics of what happened, what the pictorial evidence shows us and what went wrong in flight PK8303.
First of all, let me say, I don’t really believe the reports that the plane had:

1. Engine problems at takeoff as well

2. The engineering/maintenance department had issues with this plane or the department itself was incompetent?

Why don’t I believe this?
Well, we know that the aircraft had a pretty normal and standard flight before the first landing attempt (my guess is the first time

the pilots had the idea of some sort of problem was when the landing gear wouldn’t deploy). PK83030 took off fine, it rose to its cruise altitude with no problems at all (if there were engine problems they would have registered when the engines were at full
power/capacity

and the plane was climbing).

Also, if there was a problem in the plane’s engine at takeoff then the pilot would’ve known about it because there are systems in place that monitor the engine’s health, performance and status and relay that information to the pilot and then

there are a computer programs as well that monitor engine health and the pilot would have aborted takeoff or aborted the flight and returned has there been an engine problem at take off and would have easily landed back.

As for the second theory, let me say this that

first of all PIA is not a dummy airline. It has stringent and strict and international standard safety protocols and check ups are mandatory (as required by international law).

The A320 itself is an (And I can’t stress this enough) excellent aircraft, it’s a small

to medium sized airliner but it has an excellent safety record, it has been in PIA’s fleet for several years, PIA has 12 of these A320s and (13 before the crash) and obviously PIA has an excellent range of aerospace engineers working for them from CAE and IST as well.

The aircraft had gone through an A-check (a major flight operations and maintenance check) less than two months ago and everything was fine.
The pilot (as every pilot does) must have reviewed the plane’s maintenance checks in pre-flight, then there are the flight engineers

and ground engineers as well.

Basically we have 20-30 highly qualified and experienced people governed by strict international standard protocols neither of which had any issues in letting the plane fly, plus the plane’s normal performance during the first 99% of the flight.

Now. Let’s look at what happened in those last few fateful minutes, and this is where from an engineering point if view it gets interesting.

See, this is what actually happened deduced from the CCTV footage, runway assessment and ATC radio recordings:

The airplane flew as expected and then begun landing procedures.
It set itself into a proper approach and glide path, aligned itself via the ILS system to the runway.
The pilot initiated the dropping of the landing gear but an alarm sound went off indicating a problem with

the hydraulic system that operates the landing gear and sensor lights lit up indicating the landing gear are not engaged (may have dropped down but not fully lock)
At this point the pilot could have done three things, pulled the lever back and through again, starting the process

again (this takes around 20-30 seconds), he could overshoot the runway and try again through a go-around or he could perform a belly landing (landing without gears) (bery risky as fuel in the wings might ignite so generally pilots dump fuel before attempting a belly land but

there was no time for that)
At this point we don’t know if the pilot was aware if the landing gear was fully locked or not, only that it had a problem and the pilot decided to attemp landing.

At this point the pilot communicated to the ATC that there is a problem with the landing gear.
Here arises a conundrum and twi main theories:
1. Plane didn’t touch runway and completely aborted landing, went around for another attempt, in which the engine died and the plane

crashed.

2. Only the planes engines touched runway and then aborted, engines were fine but failed during the go around (more likely in my opinion)

Some believe the pilots had no idea of the landing gear failure and attempted to land. The gear, having not fully locked, buckled and the engines hit the ground and thus we see “skid marks” under the engines. Then the pilots, realising what had happened, throttled up

again and flew away.

Some people believe the blackening under the engine is due to engine flame out/in flight engine fire. Usually the engines blades would be bent and severely damaged and engine would fail so taking off would be a risk but apparently the engines struck the

runway minimally and were fine when the attempt was aborted and the plane started gaining altitude again.

I personally believe the engines did strike the ground but barely before the pilot decided to abort the landing.

The other theory that:
An aborted landing and a go around is what the pilot decided to do, because there was not enough distance (downrange) left between the runway and the plane that the landing gear could be engaged again.

This is where it gets interesting.
Forget about what happened before because in BOTH scenarios, at this point both the engines were working fine despite striking the runway (or the plane would not have gained altitude and gone for a go around)

Now, either the engines died when the runway strike happened or when the pilot was throttling the engine up (increasing engine power after aborting take off: A320 is at 130-140 Knots at landing so to gain altitude and stay in flight for the go around engine will have to be

throttled up) the engines flamed out.

Now, let’s stop here and understand how exactly this happens.
If the engines struck the runway, they obviously would have broken some sort of fuel or oil leading to an engine flame out this would have been a dual engine failure

with the aircraft rising from the runway but this scenario is unlikely as I don’t think engine failure immediately after the runway strike would have left the plane with enough speed to again rise and ho around. So we have to assume that the engines were fine while the aircraft

was climbing from the runway after having both engines struck the runway.
So how did the engines die?

I’m not going to bore you with the specific schematic of a turbojet engine, but basically an in flight engine fire is a major emergency in which the internal or external

part of the engine catches fire because of a bird strike, broken fuel line, broken oil pipe, electrical sparks etcetera.

Now we do know that the not one but both engines flamed out as can be seen in the photograph in which the fire’s black soot effect/skid marks

can be seen underneath both engines. Also, the RAT (Ram air turbine, a small turbine which powers essential electrical and life support systems onboard the aircraft after engine failure)

And this happened between the landing attempt and the go around.

Now let’s look at the possibilities WHY the engine might have failed during the go around:

1. Bird Strike
In my opinion, slightly plausible, but still possible. Why you ask? Well because almost 70% of bird strikes happen in one engine, not both. A stray bird flies/is sucked into

the engine, breaks the internal structure or breaks a turbine or compressor blade and a fuel/oil line is broken and fire starts and the engine flames out. This on the other hand was a two engine flame out. But they still do happen when bird density in the area is high

(Karachi airport is known to have low to moderate bird density). Also when a bird strike happens, engine blades are broken off from the impact. Look at the picture. Left is a bird hit engine and right is the engine from PK8303.

So a bird hit on both engines is unlikely and most likely the engines were damaged upon scraping the runway but survived and then finally stopped working DURING the turn of the go around.
But still we shall look at the other possibilities:

2. Oil or fuel pipe/line damaged or burst
Yes this may cause fire in the engines but then again both at the same time is unlikely but can happen.

3. Electrical spark causes fire of some sort in the combustion chamber or compressor.

Also, engine fires was suppressed. As no fire can be seen in the photo. An engine fire is normally detected and contained satisfactorily by the aircraft fire detection and suppression systems.

Nevertheless whatever happened, both engines at this time had failed.
Now is that a fatal situation? Potentially, of course BUT it can be saved.
Here let me tell you some BASICS of modern winged flight.

How an airplane flies (extremely dumbed down version):
The engine underneath the wing sucks in air and makes air go slow underneath the wing, as compared to the air which is flowing faster over the wing. This difference of air speeds translates into a

difference in air pressure (basic Bernoulli’s Principle) (lower pressure above the wing and higher pressure underneath) which gives LIFT and go UP.

Secondly, the escaping air at high speed gives thrust/push to fly forward (same principle as a rocket or a burst balloon)
Now. When the engines die out, there is loss of thrust to get the plane forward and as a consequence there is also a loss of air speed

(which gives the lift factor) flowing on the wing.
So the airplane starts to fall. Sufficient altitude and speed, aircraft can fly quite a long distance slowly coming down and swiftly gliding but obviously if you’re barely 2000 feet above the ground then you have a big problem.

My salutations to the pilot because as we can see in the ATC recording he is completely calm whereas I would be FREAKING OUT if I was piloting a 70 ton aluminium tube with no engines 2000 feet above Karachi.

He tried his best to somehow get the aircraft to the runway but sadly physics and aerodynamics came in the way. He had no lift, no thrust, a lot of drag, and the runway was too far away and tall residential buildings (which btw shouldn’t have been there) came in the way

From the final moments’ CCTV coverage we can see that the plane was in a stall position and in a stall trap (there was a loss in lift so the plane could not stay level and the nose was turning upwards which caused a further stall due to high angle of attack)

The aircraft struck the ground and broke up. Fuel caused a huge fire. 97 people died of the 99 onboard and 2 miraculously and thankfully survived. 11 people died on the ground being struck by the crashing airplane.

This is also one of the few instances where COVID-19 actually saved lives as PIA was following social distancing protocols and the flight had only 91 passengers onboard onboard while A320 can carry 170
Passengers

My conclusion:
The pilot couldn’t have done anything more to save the plane, the aircraft was fully maintained and finely engineered. It was a technical fault that no one could have predicted and was a matter of chance (as the hydraulics must have been checked preflight)

Suggestions:
1. Give more emphasis in emergency scenario training to PIA pilots. If the pilot attempted a belly landing in the first attempt, the abundant fuel might have ignited hence fuel dumping was required but beforehand.

2. Invest in modern aircraft, which have computers that monitor systems continuously and would have alerted the pilot wayy before that there had been a problem with the hydraulics of the landing gear and the pilot could have dumped fuel and attempted belly landing without

attempting the the fatal go around.

3. Some death could have been prevented if there was less civilian residential building near the airport, the aircraft might have even been saved.

Ultimately the final report will actually tell us what happened and I could be wrong.
Thank You.