United Airlines had a bad few weeks — should air travelers be worried?  

United Airlines has suffered a recent spate of flight incidents.  

They range from a tire falling off an airplane on takeoff from San Francisco International, an engine fire on a flight from Houston InterContinental to Fort Myers, an airplane sliding off the runway at Houston Intercontinental and a hydraulic system failure on a flight from San Francisco International to Mexico City. To throw even more gasoline on the fire, this weekend an external panel mysteriously disappeared off a United flight. In all incidences, there were no fatalities or injuries. 

Having a single incident over a short time horizon is not that unusual. Having several seemingly unrelated events may seem worrisome. This begs the question: Is there an issue with United or with the airplane manufacturers, or did other factors cause these events? 

To understand these events and uncover what it may mean for United air travelers — and perhaps all air travelers — one must look at the data. 

On an average day in the United States, commercial airlines operate more than 25,000 flights, carrying around 2.5 million passengers, based on the Transportation Security Administration (TSA) screening throughput at airports. 

Air travel in the United States has been remarkably safe for many years. The last reported commercial airplane crash occurred on July 6, 2013, when Asiana 214 crashed as it approached San Francisco International Airport for landing. Pilot error was determined to be the cause of the crash. 

Among U.S. carriers, the last crash was on Feb. 12, 2009, when Colgan 3407 crashed on its approach to Buffalo-Niagara International Airport. This crash led to sweeping changes for pilot certification and rest rules, which most likely has led to safer air traveler over the past 15 years. 

In contrast, over 40,000 people were killed on highways in 2022. By any reasonable measure, boarding an airplane for a two-hour flight is significantly safer than driving the same route for 12 hours. 

Ensuring that every flight is as safe as possible demands intricate coordination between the airlines, the airplane manufacturers, the Federal Aviation Administration (FAA) and airport authorities. These partnerships are designed to facilitate safe and efficient air travel. 

So what happened with so many United flight incidents in such a short period of time? 

Let’s look at them, based solely on public information available. 

The tire falling off the flight out of San Francisco International is quite rare. Airplane tires are replaced on a regular schedule and are routinely checked for wear and tear to ensure that they can handle the takeoffs and landings that every plane must go through several times per day. In this case, when a tire unexpectedly falls off, something went awry during the safety checks and routine maintenance, and most likely, the last time the tire had been replaced.  

The good news is that large commercial airplanes have several tires, so the risk to passengers was minimal. The greatest risk was to the area where the tire settled after dislodging from the airplane. 

The second incident, the engine fire on the flight out of Houston Intercontinental, was caused by bubble wrap being ingested into the engine. Though such an incident is highly unusual, jet engines are large and can suck in debris (or birds). In most cases, nothing occurs. In this case, a fire erupted. For safety purposes, fuel is cut off to the affected engine, so the fire does not spread, with the remaining engines used to propel the airplane to a safe landing at the nearest airport. 

The third incident, an airplane skidding off the runway upon landing at Houston Intercontinental, is also highly unusual. The weather conditions were unfavorable at the time, creating a level of uncertainty following landing. However, airplanes land in inclement weather every day. Information as to what caused the incident is still under investigation, though some error (either pilot or air traffic control) is a plausible explanation. 

The fourth incident, a hydraulic system failure, falls within the realm of highly unusual as well. Airbus planes are designed with a redundant hydraulic system, so when one fails, two others are available. The risk to passengers during this incident was minimal. 

The same can be said about the missing external panel. 

The FAA takes all airplane incidences seriously. It is this attention to detail that imbues confidence in air travel and ensures that travelers remain safe on every flight. This contributes to the pristine safety record enjoyed by commercial air travel over the past 15 years. 

Whether there are some underlying issues with maintenance at United remains to be seen. Given the number of flights they offer, this is highly unlikely. If anything, maintenance records will be reviewed but are unlikely to produce any meaningful insights.  

What United most likely experienced the last couple of weeks was a string of bad luck. Social media has a way of amplifying any such incident. The good news is that each incident will be investigated, ultimately leading to an even safer air travel experience for all. United, and all the other commercial airlines, have a vested interest in making it so.  

Sheldon H. Jacobson, Ph.D., is a professor of Computer Science at the University of Illinois at Urbana-Champaign. He applies his expertise in data-driven risk-based decision-making to evaluate and inform public policy. He has also studied aviation security for nearly 30 years.