Just as I was finishing my lunch on February 14, 1990 — in my National Aeronautical Laboratory (NAL) office on Bangalore’s old Airport Road — I heard a commotion. Everyone seemed to be running up to the terrace of our building.
“We just saw a plane flying very low and it appears this plane has crashed and is on fire.”
“Was it a MiG-21?”, I asked.
“No it is some Indian Airlines passenger plane.”
I too rushed up with the crowd to the terrace. I didn’t see the actual aircraft wreckage but I saw big black smoke billowing out. We would later learn that this was the IC 605 Airbus A320 flight coming in from Mumbai. About 90 out of the 145 passengers and crew aboard perished.
The cause of the air crash was a mystery. Since everything apparently happened very suddenly, crash investigators were hoping to find a lot of clues from the aircraft’s cockpit voice recorder (CVR).
A few weeks after the crash I heard rumours that the CVR of the ill-fated aircraft had been sent to NAL for analysis. I promptly dropped by to have a chat with the investigating scientists. “This is top secret”, they told me. “Don’t tell me your findings, just tell me what are the problems you are investigating”, I implored.
It turned out that the Court of Enquiry wanted answers to two questions: One, at a critical moment before the crash, the CVR records one of the pilots saying: “Hey, we’re going down!” Who said this? Was it the check pilot (CP) Capt S S Gopujkar, or the pilot flying (PF) Capt C A Fernandez? Two, what could be the origin of a metallic click sound heard in the cockpit: Was it the throttle lever movement or the sound of the cockpit door shutting?
NAL provided both the answers using cepstrum analysis: Yes, it was Capt Fernandez’s voice, and the metallic click sound was indeed because of the throttle lever movement.
I have always been curious to figure out how NAL’s investigations fitted into the overall jigsaw puzzle, but, till recently, all the facts relating to the crash were not in the public domain. We had conjectures, but nobody had the true story.
Looking back, 22 years later, it would indeed be correct to say that the plane crashed because the pilots were not sufficiently familiar with A320 procedures and displays. Compared to other planes flying those days the A320 was a very different flying machine.
The essential difference was that the A320 used the fly-by-wire (FBW) technology. In a conventional aircraft the pilot was in direct contact with the actuator; so if he opened the throttle more, the actuator immediately gave him more power. But in the A320 the pilot’s command was first directed to an on-board computer — and the actuator responded only when the computer determined that it is okay to do so.
The big idea was that the computer would take over many of the routine tasks and leave the pilot free to manage the more critical flying manoeuvres.But there was also a big concern: how would pilots adapt to these vastly changed flying conditions? What would happen if the pilot and the computer failed to communicate correctly?
Alas, that’s exactly what happened that fateful afternoon on February 14, 1990. As the plane came down to land the pilots expected the plane to behave in a certain way. But, failing to get the right instruction, the plane continued to ‘misbehave’ … till it was too late. What makes things even more poignant is that the pilots had several opportunities in the dying minutes to correct the situation … but they didn’t.
I will now attempt to put together the story of the last few minutes of IC 605’s flight. This has been done before: for example, read through this long discussion on the Tech Ops forum of Airliners.net, this vivid 2-page reconstruction in Flight International or this long description in a Flight Safety newsletter. A brief accident description appears on Aviation Safety Network, and on India’s DGCA website. The CVR transcript of the last few minutes makes a chilling read, and there is also a curious hypothesis to explain Capt Gopujkar’s responses in Michel Asseline’s book: Le Pilote: Est-il Coupable?
I have to confess that my narrative has holes; if a real pilot reads it he will chuckle at my ignorance and remark on my stupidity. But I do hope the lay reader will have a better idea of an air crash that should never have happened.
February 14, 1990. 12.59 pm. It is another bright and gorgeous day over Bangalore with hardly a cloud in the blue sky. Indian Airlines’ flight IC 605 from Mumbai — 8km away and cleared to descend to 4600 ft above sea level — is preparing to land.
The 139 passengers aboard had fastened their seat belts. The swanky new Airbus A320 aircraft seemed so much more comfortable than the ageing Airbus A300 and Boeing 737 aircraft that Indian Airlines used to fly before.
It had been a cheerful and uneventful flight so far. The senior pilot, Capt S S Gopujkar, was the check pilot (CP) occupying the right seat in the cockpit. His junior, Capt C A Fernandez, sitting on the left, was actually flying the aircraft (PF). Playbacks of the cockpit voice recorder (CVR) confirmed this feeling of bonhomie. As the air hostess briefly entered the cockpit to serve the pilots tea she was singing Doris Day’s famous song: que sera sera, whatever will be will be … She would then leave the cockpit making sure that its door clicked as she shut it.
Now approaching the ground, the plane was still flying in the ‘open descent’ mode. In this mode, the aircraft engines are at idle throttle; a frequent A320 flier will recall those last few minutes before landing when the plane engines seem to turn silent, and the plane appears to be sinking bit by bit. … rather like a ship being tossed around gently by tiny waves.
At 1.00:42 pm the Bangalore runway came into sight. The pilots disengaged the autopilot and established contact with the control tower. At 1.01:40 pm, the aircraft display indicated that the plane’s altitude was just under 5000 ft and its approach path was 600 ft higher than the normal glide path.
This wasn’t alarming. The first reaction of the pilot flying, Capt Fernandez, was to request a ‘go-around’ — he would climb to 6000 ft, do another chakkar and come back better aligned to the normal glide path. The check pilot, Capt Gopujkar, responded to this request by asking: “Go round you want? Or you want vertical speed?”. As the commander of the flight, was he gently recommending the second alternative?
If the pilots would have proceeded with the go-around, the emergency that was to follow could have been averted.
When offered the alternative, Capt Fernandez, at 1.01:54 pm, chose the vertical speed option. Since the plane was a little higher than the normal glide path, Capt Fernandez asked for a higher descent rate of 1000ft / min, instead of the normal rate of 700 ft / min. This faster descent increased the aircraft speed to 275 km / hr — higher than the recommended speed of 240 km / hr — but it helped the aircraft regain the normal glide path. The aircraft was also now in the vertical speed mode — the correct mode for landing.
So at this stage, all was well. At 1.02:17 pm, the air traffic controller cleared IC 605 for landing. At 1.02:23 Capt Gopujkar completed the landing checks. At 1.02:34 he asked the crew to be “at your stations for landing”.
Realizing that the aircraft has regained its normal glide path, Capt Fernandez reported at 1.02:42 that he had now selected a “700 ft rate of descent”. But how did he do this? Which knob did he really select? Did he select a vertical speed of 700 ft / min or an altitude of 700 ft? (these two knobs are next to each other on the display panel).
Tragically, it appears that Capt Fernandez selected the wrong knob; and, even more tragically, this selection sent the plane back into the open descent mode with idle throttle. With no power to arrest the descent, the aircraft started rapidly losing speed and height. The plane was now in deep trouble.
The pilots had to take immediate action; precious seconds were ticking away as the plane kept losing speed and height. But, strangely, the pilots seemed unaware of the impending emergency! Or did they believe that the plane’s computer was configured to guarantee speed protection … and this would ensure a safe landing?
At 1.02:49 pm, the plane’s radio altimeter called out “400 ft”. This probably alerted Capt Gopujkar in some way because at 1.02:53 pm he suddenly observed: “You are descending on idle open descend ha, all this time!”. And as the altimeter called out “300 ft” at 1.02:56, Capt Gopujkar asked: “You want flight directors off now?”
Capt Fernandez confirmed at 1.02:57 pm that his flight director had been put off, but, at 1.03:00, Capt Gopujkar tells him: “But you didn’t put off mine”. Why didn’t Capt Gopujkar put off his flight director himself?
If both the flight directors had been put off at that point, the plane would have gone to the speed mode, and enough engine power could have been generated for a possible recovery even at that late stage.
The plane continued to hurtle downwards and at 1.03:10 pm, when the plane was less than 200 ft from ground, Capt Fernandez suddenly realized the gravity of the situation and exclaimed: “Hey, we’re going down!”. Capt Gopujkar, himself stunned now, could only respond with “Oh, shit!” Those were his last recorded words.
Now desperate, Capt Fernandez pulled the stick back fully in what would be his last throw of the dice. He was telling his plane: “I want you to take-off and go-around (TOGA) …Now!” At this point he was a mere 135 ft from ground.
To attempt TOGA, the act of pulling the stick back fully has to be accompanied by the act of pushing the thrust levers forward. Unfortunately, there was a delay of 2 seconds between the two actions. And remember that the Airbus A320 was a FBW aircraft! So that wretched on-board computer might itself have needed a second or more to clear the attempted take-off.
The plane eventually made a soft landing on the golf course 2300 ft away from the runway. After rolling for some 80 ft, the plane did briefly lift off again as TOGA started getting activated. But it failed to clear a 12 ft embankment in the way! This impact sheared off the engines and the gear, and the plane crashed again this time with twice the ferocity. Soon it was enveloped in a deathly blaze.
If the lever throttle had been pushed and the stick fully pulled back even 9 seconds before the first impact, the plane could perhaps have still taken off to safety. Here is a clip of how an Airbus A320 can take off even at the last moment.
While everyone involved in investigating this crash conveniently blamed the pilots (remember that two Airbus A320 aircraft crashed in quick succession around that time, and Airbus Industrie was desperate to protect its brand new plane), we must ask if the pilots were really completely to blame?
Why should forgetting to put off a flight director lead to such terrible consequences? Why should displays be so confusing? Why should an incorrect altitude selection change the flying mode without any warning to the pilots?When the plane was losing speed why didn’t the pilots receive alerts, e.g., with a shaking of their seats?
I want to end off by commenting on the curious demeanour of Capt Gopujkar. If you read the CVR transcripts you don’t find a single sign of panic or a single expression of despair from him (except at the very end). Why? Remember that Capt Gopujkar was still in command and Capt Fernandez was still his student; indeed the the guru-talking-to-chela feeling is palpably visible as your read the transcripts. My best guess (and this was articulated by a French pilot with whom he co-trained at Toulouse) is that Capt Gopujkar was privately certain that the speed would be protected; so even as the plane ran into trouble he perhaps only saw this as an opportunity for a stern examination of this pupil. Even he couldn’t have imagined that this was going to be a fatal failure.
— The two queries posed to NAL only sought to identify the identity of the pilot flying (a voice analysis showed that Fernandez and Gopujkar had very different peaks, so identification was easy), and verify if Capt Fernandez did push the throttle lever in the dying seconds (the contrary view was that Fernandez never pushed the lever and the click sound might have been of the cockpit door shutting; the sound of the cockpit door shutting as the air hostess sang que sera sera was used as the sample in the comparison).