When Analytics Meets Aeronautics

June 10, 2020

in Bhogle the Mind, Careers in Statistics

By Srinivas Bhogle

The data invasion in aeronautics probably began in the late 1980s when Airbus Industrie unveiled Airbus A320, the world’s first civil fly-by-wire (FBW) aircraft.

In a FBW aircraft, there is a computer introduced between the pilot and the control surface. So, if the pilot wants to yaw sharply to the left, his ‘request’ is first submitted to the computer, and it is the computer that tells the rudder to carry out the maneuver.

FBW technology makes sense because it allows the pilot to delegate many of the more routine or mundane tasks to the computer while being free to manage the more important task of safely flying the aircraft. For example, landing in poor weather or in zero visibility becomes a lot simpler.

As readers can guess, the FBW technology first originated in the design of fighter aircraft. A fighter aircraft is as different from a passenger aircraft as chalk is from cheese. A fighter aircraft is all about maneuverability, speed and control, while a passenger aircraft is really about stability, safety and comfort. When the pilot just has a few seconds to successfully complete his mission, the computer on board can provide a crucial winning advantage.

But why would Airbus want to bring in FBW technology in passenger aircraft? The decision was both a surprise and a worry. Airbus’s rival Boeing reacted in the early days by saying it wouldn’t attempt FBW technology in civil aircraft. The introduction of Airbus A320 proved to be indeed difficult. There was an early crash in France, and then the more tragic crash in India.

One happy consequence of FBW technology was that civil aircraft started churning out much more data; something that you would expect when you insert a computer onboard. This raw data of course required mediation, processing and management, but it also made it so much easier to measure flying performance, analyze accidents and design better aircraft. Today, big data is poised to change the future of aviation.

Here’s an interesting Airbus A320 story to explain how things began changing. Many years ago an impatient pilot was waiting to take off his Airbus A320 aircraft from the old airport in Hyderabad, India, but the traffic controller kept asking him to wait. The angry and agitated pilot wanted to know why.

“I see a flock of gulls at the other end of the runway, and you must wait till they fly away”, the traffic controller told him. The pilot looked as far out as he could see, but saw no gulls. So he decided to take off anyway.

What the pilot briefly forgot was that there was a slight hump in the middle of the runway that obstructed his visibility. He started his run, speeded up, attained a speed of 110 knots (after which you must take off) and then was horrified to find that there was indeed a flock of gulls.

This was big trouble, and the pilot had to make a premature take-off before reaching the prescribed take-off speed of about 140 knots. Fortunately, the plane took off safely avoiding bird hits, but its tail brushed ever so slightly with the runway in the process.

When a maintenance engineer asked why the tail was damaged, the pilot pretended that he didn’t know. But a simple plot mapping altitude to take-off speed nailed his lie: data from the onboard computer successfully established that the plane took off well before attaining the required take-off speed.

Modern aircraft are now so safe that pilots can afford to be careless, and they often are. Most passengers recognize a hard landing, but there are a dozen other ways in which pilots abuse aircraft. This abuse is not immediately noticeable but it eventually begins to show up with a higher frequency of maintenance visits. This, in turn, translates to significantly higher insurance costs.

Indeed, this used to be a major dilemma for airline managers: How do they tell their prima donna pilots who are flying their planes badly? Big data and stylish 3D visualization and animation now make this possible. Every flight path (especially during landing and take-off) can be visualized, and the pilot’s performance can be continually monitored. These visuals are so splendidly ‘textured’, and have such good refresh rates, that they are almost perfect replicas of the actual flying path.

I believe that big-data analytics will change completely our ideas and processes involved in aircraft maintenance and aircraft accident investigation. Even today, aircraft maintenance processes tend to be very structured. There are rules that say that a certain part must be checked after ‘x’ flying hours, and another after ‘y’ flying hours. Why ‘x’? Does this ‘x’ depend on the age of the aircraft, or on the terrain in which the aircraft flies? How did we determine the value of ‘x’ in the first place?

I suspect that a lot of these parametric values are coming out of ancient flying manuals, or from old models that determined a certain probability distribution for part failure. With the influx of big data we can play the game very differently. We could, for instance, determine maintenance schedules based on simulated sample flight paths and correlations that seem to recur.

Aircraft accident investigation, too, continues to happen in the traditional Sherlock Holmes style: try to put together possible hypotheses based on recorded cockpit conversations, correlate these hypotheses with the data recorded in the digital flight data recorder (sometimes called a ‘black box’ although it is actually bright orange in color), and undertake metallurgical investigation of the wreckage. Big-data analytics now offers the opportunity to move from the qualitative to the quantitative: e.g., image processing of damaged surfaces and creation of big-event databases.

There’s much more we can talk about. Oren Etzioni’s big-data analysis of aircraft ticket pricing (described in the admirable new book on Big Data by Viktor Mayer-Schoenberger and Kenneth Cukier), the emerging idea of ‘free flight’ (instead of flying only in well-defined air ‘corridors’) that will suddenly create an immense new expanse of flying space in the skies, variants of ticket-pricing models, etc.

I will end with a comment by one of India’s leading aviation entrepreneurs: “It is all rather simple. Just make sure that your planes are flying in the skies. Planes earn money when they fly, but lose money when they are on ground!”