“Mayday, Mayday, Mayday! Fuel! We need an airport to land sir immediately”

The desperate radio call crackles through monsoon-darkened skies over northern India. Through heavy rain and threatening thunderstorms, a passenger jet carrying 162 souls is running dangerously low on fuel.

After a failed landing attempt in Delhi, then another at Lucknow, the pilots find themselves trapped. Every route they consider is blocked by towering storms. Their fuel levels are dropping fast. Can they find a safe path to land before they completely run out of fuel?

This is the story of Vistara Flight 944.

It’s 15 July 2019. At Mumbai International Airport, the crew of an Airbus A320neo prepares for a routine domestic flight to Delhi. In the left seat sits a 29-year-old captain with over 8,500 flight hours, the vast majority gained in the A320 family. The captain will be ‘pilot flying’ today.

Over in the right seat sits the 28-year-old first officer with 1,600 hours total experience, including nearly 400 hours in the A320. For this trip, the first officer will be ‘pilot monitoring’.

Their one-year-old Airbus A320-251N, one of several models in the A320neo family, is equipped with CFM International LEAP-1A engines. The “neo” stands for “New Engine Option”, marking an upgrade from the original A320 series with more fuel-efficient engines. As we shall soon see, they’ll desperately need every last drop of that fuel efficiency.

On board are 155 passengers and 7 crew members, including both pilots. Normally, this flight from Mumbai to Delhi takes just over 2 hours. It’s mid-July – peak monsoon season in Northern India – when flight crews regularly demonstrate their expertise in managing challenging weather conditions. But today, let’s just say, this crew’s decision-making would be tested like never before.

Even before takeoff, the seeds of what’s to come are buried in the paperwork. The transit briefing sheet lists Ahmedabad as their primary alternate airport and Lucknow as their secondary. However, the operational flight plan shows something different – Lucknow as primary and Jaipur as secondary. It’s a small detail, easy to overlook in the routine of pre-flight preparations. The captain accepts the plan. These two documents serve different purposes – one guides the crew’s planning while the other determines fuel calculations. But this discrepancy between both documents, seemingly minor at the time, will soon play a big role.

At 3:18 PM local time, Flight 944 has a normal takeoff from Mumbai. As the plane climbs, the passengers and crew settle in for what should be a regular flight north to Delhi. They took off with 8,274 kilograms of fuel – enough for the trip to Delhi plus the mandatory reserves that allow them to reach alternate airports if needed, and an additional buffer of 1,001 kilograms.

But high above the Indian subcontinent, monsoon storms are building. Weather reports already indicate concerning developments ahead.

As they continue their journey, the pilots don’t check the weather at the airports they’re passing – information that could prove valuable if their plans need to change. Ahmedabad slips past below, then Udaipur, then Jaipur – each one a potential safe harbour should things go wrong. Instead, the crew’s attention is focused ahead on Delhi.

The first officer begins the descent. They receive an update from their airline’s operations centre: Delhi’s weather is deteriorating rapidly. Winds of 20 knots gusting to 30 and Runway Visual Range is down to 1,300 metres on runway two eight, 1,000 metres on runway two nine, with thunderstorms and rain showers at the airport. Then comes the first warning from Air Traffic Control – expect delays on arrival at Delhi.

“I think we have to divert,” the captain says, more than twenty minutes before they attempt to land. “I do not think we will be landing in next at least 25 minutes.” The crew now faces their first major decision point. They have additional fuel of 1,001 kilograms on board – enough to hold over Delhi, hoping the weather improves. But using this fuel for holding means burning through what they’ve reserved for reaching their primary alternate airport, Ahmedabad.

Despite this risk, the captain makes a choice – they’ll enter the holding pattern and wait for the weather to improve. With each passing minute circling above the storms, their fuel reserves continue to shrink. Their Minimum Diversion Fuel (MDF) was 2,914 kilograms. Critically, they’re burning through the extra fuel that would have allowed them to reach Ahmedabad – their original primary alternate airport.

The decision to hold has effectively locked them into choosing either Delhi or Lucknow as their only viable options. “Will be very close,” the captain observes. “One Go Around and we will have very less fuel to divert.” A go-around – where pilots must abort a landing attempt and climb back up for another try – burns significant fuel.

Air traffic control begins working to fit them into the landing sequence. When the controller asks if a position 40 miles from touchdown is acceptable, the captain initially calculates this means about 15 minutes to landing. “Anyway,” he goes on, “we will just continue what he is making us do right now and let us see how it goes but I am not landing at less than 3.5 tons over here.” The captain’s determination to stick with the original plan, despite deteriorating conditions, was beginning to show signs of decision-making that the investigation would later scrutinise.

Delhi Tower clears them for approach to runway two nine, reporting winds zero six zero degrees at ten knots. But as they descend through the rain, conditions rapidly deteriorate. “We can expect strong tailwinds at touchdown also,” the captain warns. “At anytime strong tailwinds then we will go around” He notes that the “runway looks really wet and probably contaminated as well because of the weather.” At just a couple of hundred feet above the ground, they encounter strong tailwinds. With the runway wet from heavy rain, they make the prudent decision to go around.

When the radar controller asks for their go around reason, they report “strong tailwinds at 200 feet.” They have limited options. They set course for Lucknow – despite it being farther than other alternatives. The path ahead is riddled with storms, forcing them to deviate significantly south of their planned route. And each deviation burns precious fuel.

Then comes a suggestion from Delhi Air Traffic Control that will later prove significant: “Vistara nine four four, any interest for Jaipur, Sir Jaipur is vacant.” The first officer’s response is quick and definitive: “Negative Sir, Lucknow is our alternate, Vistara nine four four.” This response reveals a complex reality of airline operations. Lucknow was what’s known as a “suitable alternate” – an airport where Vistara had ground crews and arrangements in place to handle diverted flights. Jaipur was only an “acceptable alternate” – technically available for landing but without the airline’s ground support infrastructure. Though closer and available, diverting to Jaipur would mean significant delays and logistical challenges for both crew and passengers.

Meanwhile, in the cabin, 155 passengers likely sat unaware of these mounting complexities, perhaps only noting the occasional bump of turbulence as their aircraft deviated around the storms.

This distinction between suitable and acceptable alternates, seemingly minor during flight planning, was now influencing the flight crew’s decision making. The aircraft climbs away from Delhi but immediately encounters the first signs of trouble. The storms force them to turn further and further south – eventually deviating 40 miles from their planned route. Each turn away from their destination burns even more of their dwindling fuel.

After they finally get clear of the weather and program the approach into Lucknow, their Flight Management Computer predicts they’ll land with about 1,600 kilograms of fuel – less than planned, but still above minimums. That calculation, however, assumes they’ll be able to fly directly to their destination. The towering monsoon clouds ahead of them, unfortunately, suggest otherwise.

“Any delay expected? Vistara nine four four,” the first officer radios as they approach their diversion airport. ATC responds with “no delay as of now” and clears them for vectors to Runway 27’s ILS approach from the south. The weather, however, has other plans. As they draw closer to Lucknow, conditions deteriorate rapidly. A troubling sign appears – the aircraft ahead of them discontinues their approach due to the weather.

At 17 miles from touchdown, they receive worrying news – the runway visual range has dropped to just 475 meters in heavy rain, well below their required minimums. Moments later, it deteriorates further to 275 meters. Through the windscreen, there’s nothing but gray.

“Roger, discontinuing approach,” the first officer informs Lucknow Tower. But instead of immediately climbing away, the crew makes another critical decision. They delay their climb, hoping the weather will improve quickly enough for another attempt.

Five precious minutes pass before they finally request a climb. Air Traffic Control can only clear them to 4,000 feet to avoid conflict with other traffic at higher altitudes. Trapped at this relatively low altitude, they’re burning more fuel than they would at a higher cruising level.

The situation intensifies. The crew declares “Minimum Fuel” to ATC when their estimated fuel on board drops to 1.1 tonnes. This tells controllers they’ve committed to landing at Lucknow, and any change to their clearance might result in landing with less than their required final reserve fuel – in this case, 1,150 kilograms, calculated to provide 30 minutes of flying time in holding conditions. But the weather continues its relentless deterioration. The runway visual range drops further to 225 metres. With fuel warnings now illuminated in the cockpit, the captain makes this distress call: “Sir, Vistara nine four four. May Day May Day May Day Fuel. We need an airport to land sir immediately, Vistara nine four four”

In what seems like a final attempt to find clear weather, they request clearance to divert to Kanpur. But there’s severe weather along that route. They then consider Prayagraj (formerly Allahabad), which appears to have a clearer path.

To make matters worse, neither airport is in their navigation database and they don’t have approach charts for either one. With fuel now showing just 500 kilograms remaining, they face a super-critical choice: continue towards an unfamiliar airport, or return to Lucknow. Next comes an important update from the controller: “Vistara nine four four, radar, visibility has now improved at Lucknow, visibility is 600 metres.” Seconds later: “Visibility is 800-1,000 metres now. And if you wish, you may turn back for Lucknow.”

The crew must decide. At this moment, they’re 58 miles from Prayagraj but only 37 miles from Lucknow. With their remaining fuel so critically low, every mile counts. The captain makes the decision – they’ll return to Lucknow.

“Lucknow, Mayday Vistara nine four four, we are turning back to Lucknow,” the first officer transmits. There’s literally no fuel margin left for another diversion if Lucknow’s weather deteriorates yet again. Lucknow controllers clear them for the shortest possible vectors to the ILS approach to Runway 27. As they’re now essentially ‘running on fumes’, so to speak, their only real option is a successful approach and landing on their first attempt-can they do it?

Through the rain, the runway at Lucknow finally comes into view. It must have been a sight to behold for the captain and first officer. Behind them in the cabin, 155 passengers remain blissfully unaware of the critical fuel situation. This was the moment of truth.

At 6:48 PM local time, Flight 944’s wheels finally touch down safely on the rain-soaked runway at Lucknow. The final fuel reading shows just 348 kilograms remaining – far below legal minimums and dangerously close to total fuel exhaustion. To put that 348 kilograms of fuel into perspective, they really only had mere minutes to spare. Probably barely enough to taxi from the runway to the terminal building! Had they continued to either Kanpur or Prayagraj, investigators would later conclude, they would have completely run out of fuel midair!

The passengers disembark, most likely still completely unaware of just how close they came to possible disaster. Thankfully, nobody was injured and there was no damage to the aircraft.

An investigation was carried out by India’s Aircraft Accident Investigation Bureau. It found the main reason Flight 944 ended up in such a dangerous situation was the pilots’ growing fixation on landing at Lucknow, even as weather deteriorated and fuel ran low. The first officer’s failure to assertively challenge the captain’s decisions allowed increasingly risky choices to compound.

The airline contributed to the situation through unclear policies about alternate airports and by failing to provide adequate guidance about safer alternatives during the flight, despite having comprehensive weather data available. It wasn’t about one person making a mistake, but rather a system of procedures and communication that made it difficult for the pilots to make the safest choice.

Every incident like this becomes a learning opportunity that makes commercial flying even safer.

📄 SOURCES Final report: https://finalreports.net/2019/VT_TNH_AT_LUCKNOW.pdf