As a Delta pilot, I know all the hidden signs there's a serious problem. Passengers would never board if they knew how close catastrophe lurks...

They don’t teach you how to fly an airplane with your knees in flight school - for obvious reasons.

Yet this is exactly what I found myself doing shortly after take-off from Tulsa, Oklahoma, one morning in 2002.

Moments earlier, the function that reduces the force of the plane’s nose as it pitches upwards had failed without warning — just as we lifted off with a planeload of passengers on board.

Usually a mechanism called the Stab/Mach Trim would have kicked in and allowed me to fly the plane with the lightest of touch.

But on this day, I flicked the switch and…nothing.

I held onto the control column as long as possible with locked arms, wrestling to keep it pushed down, but as the fatigue in my arms became excessive I placed my knees on it to help.

If we couldn’t turn this plane around immediately and land there was only one outcome; we would stall mid-air, maybe even flip, and fall out of the sky like a rock.

I’ve been a licensed pilot for more than three decades. For 10 of those years, I flew as a commercial pilot for Delta Connection as a first officer and then as captain. I’m also a qualified accident investigator.

Over the past few months, the news has been peppered with alarming stories of air crashes and near misses. It started with the horror of the DC crash in Washington’s Reagan Airport late January. Sixty-seven people died when a passenger jetliner collided with a Black Hawk helicopter on a training flight.

Two days later a small medical airplane crashed over Philadelphia killing all six on board and one on the ground.

The following month a regional airline craft crashed in Nome, Alaska killing 10. Two near misses followed – one when a Delta flight’s cabin filled with a haze that forced it to make an emergency landing in Atlanta and the second when one crash landed and flipped at Toronto’s Pearson International Airport.

So, the assertion that air travel remains the safest mode of transport we have, might ring hollow - trust me it is.

But it’s also true to say that, for the most part, the people in the back of the plane have no idea what we’re doing up front and often for very good reason.

Any pilot will tell you we have seen our share of near misses, cataclysmic weather systems and technical failures – but in most cases the passengers remain blissfully unaware.

On that day flying out of Tulsa all I could think about was Alaska Flight 261 – as an accident investigator I have a mental archive that may not be comforting but can be invaluable.

Alaska 261 crashed off the West Coast killing all 88 on board back in 2000. I knew it had the same tail design as our craft and had suffered a fractured jack screw. I was also horribly aware it was one of the potential explanations for what we were experiencing. All I could think was, ‘Oh crap I hope it’s not that.’

I was first officer at the time. The captain and I ran through our standard troubleshooting check list. When that didn’t work, we told Air Traffic Control we’d declared a state of emergency and were circling back.

We asked for fire trucks, a 15-mile final approach – the standard is five – and told them to keep us away from the city. I had to learn how to fly this plane in real time and I didn’t want casualties on the ground if we crashed.

You don’t want to tell passengers, ‘The airplane is having significant flight control problems,’ so we simply said we were returning to Tulsa and not to be alarmed by the fire trucks that would be waiting for us on the ground.

In the end we had a good outcome and the passengers never knew how close we had come to disaster.

There was nothing heroic in what we did that day. It’s a pilot’s job to keep their head and when something goes wrong you rely on your training and work with what you’re dealt.

Sometimes that means using your experience and going against what Air Traffic Control tells you. I was once forced to do just that on a flight from Cincinnati to New York’s JFK.

That’s a busy airspace and the frequency is very, very jammed so it can be hard to talk to the controller. We were flying at over 500 miles an hour and I could see we were about 20 miles from a very large thunderstorm – that distance was disappearing fast.

We were at 30,000 feet and I could see that this weather system was stretching above us, up to 60,000 feet or so and it was full of hail which is incredibly dangerous. Clearly, I’m not going to fly through that, so I told the controller I needed an adjustment to my flight path.

We request changes in degrees, so I asked for 20 to the right and was denied, then I asked for the left and was told they were unable to accommodate that which took my first officer and I by surprise.

We looked at each other and realized, ‘Well this isn’t going to work.’ I knew that if I flew into that system, apart from horrendous turbulence, my windshield would likely fracture, and I could lose both engines due to hail damage.

That’s happened before to aircraft that have accidentally flown into a hail shaft and resulted in them having to do off airport crash landings in fields.

I told the controller, ‘I’m giving you a choice of which direction you want us to go – left or right. And if you’re not going to choose, I’m going to declare an emergency and make that choice for you.’

I wasn’t scared in that moment. I knew I had clear skies to the left and to the right – I had two escape routes and as a pilot I could use my authority to take one.

I also had my Traffic Alert Collision Avoidance System (TCAS) on board, so I knew that by deviating from my path I wasn’t going to accidentally fly into the path of another aircraft without warning.

That is a very valuable system to any pilot because mistakes are made, airspaces can be crowded, and I would bet that pretty much every working pilot has relied on it at some point.

I remember on one occasion I was mid-flight over Cleveland, and it alerted, ‘Traffic! Traffic! Traffic!’ The box started screaming, ‘Climb! Climb! Climb!’

A controller had made a mistake and put us too close to another airplane. In that moment the TCAS system communicates with the other plane’s box and while it tells us to climb it will be telling the other plane to descend.

I will never forget looking out of the cockpit window, trying to spot where the other craft was and seeing a pilot looking up at me from a jet directly below us. That was pretty cool – and it was pretty close.

But, when you’re in a busy airspace and everyone is stacked really tight, you’re not just watching for the plane below you as you ascend, you’re watching that you’re not climbing into someone else’s flight path.

That does happen – it’s called the domino effect - where one plane avoiding another triggers a whole stack of flights to climb or descend out of each other’s airspace.

Again, it’s something passengers are very unlikely to register. They may notice a slightly more aggressive climb than they’re used to but the TCAS never instructs pilots to do violent adjustments.

Similarly go-rounds are very common - when you’re coming in to land and see another aircraft ahead of you moving too slowly on the runway for example, and you pull up and go around again.

These incidents may sound dramatic but this is what we train thousands of hours for and it’s why we keep training and testing rigorously throughout our careers. I don’t know a single pilot who has reached a point in his career where he’s stopped learning.

Airplanes are complicated machines. We train for all the standard stuff but it’s the strange stuff you have to be on guard for – like a Stab/Mach Trim that fails as you’re coming off the runway.

Normally we work as a team but, every once in a while, time is short and you have to step up and make the decision. As captain of a plane, you are responsible for the people on board and your authority supersedes that of the controller or anyone else on the ground or in the air.

That’s why when you’re a pilot you always have a back-up plan…if not two.

Shawn Pruchnicki is an Assistant Professor at The Ohio State University in the College of Engineering. He was a Delta connection pilot for 10 years and trained in accident investigation at the NTSB Academy. He has testified to the US Senate on the current Boeing safety culture and manufacturing problems and his research into aviation safety has been published worldwide including by NASA and the FAA.