Top 5 Reasons for Tarmac Delays

By: Stephanie Crawford
woman staring out of an airplane window
Stuck waiting on the tarmac? Wonder what's going on out there? This article describes the top five reasons for your delay.
David De Lossy/Photodisc/Thinkstock

Imagine this scenario: You've just stowed your carry-on luggage in the overhead bin, turned off your mobile phone and settled into your window seat with a good book. After a few minutes, the captain announces there's an issue with some important-sounding part of the airplane and that it's going to take about half an hour to repair. Meanwhile, a thunderstorm rolls in and other flights get backed up waiting to take off or land. Two hours later, about the time you should have arrived at your destination, your flight finally takes off.

If you fly a lot, chances are good that you'll experience occasional delays. Data from the U.S. Department of Transportation reveals that out of 6,450,118 domestic flights from January through December 2010, 79.8 percent were on time. That was as high as 85 percent in April and September and as low as 75 percent in February.[source: traffic carefully, even when every flight is on time.


Even when you find your flight delayed, you probably won't experience the extensive delays and overlapping causes described above. In fact, starting in April 2009, the U.S. DOT could fine airlines if passengers on an airplane with 30 seats or more were stranded the tarmac for more than three hours [source: Stoller]. This article looks at the top five causes of flight delays at U.S. airports that could leave you stranded on the tarmac.

5: Delayed Crew Members

flight atttendants on airplane
Federal regulations ensure that your flight crew is well-rested and ready to fly.
Digital Vision/Thinkstock

Crew delays mean flight delays. For example, if a flight crew member calls in sick, the airline has to scramble for a replacement at the last minute. Crew members might also be late arriving due to delays on their previous flights.

When flight delays are long, crew delays are even more likely, as crew members must stop working to comply with federal regulations. Those regulations require that memebers of a flight crew limit the lengths of their shifts and rest a minimum amount between them. For example, on a domestic flight, a single pilot can serve on a normal shift of eight hours in 24-hour period, and two pilots working together can work a 10-hour shift [source: e-CFR, 91.1059]. Each pilot must then rest at least eight consecutive hours before starting the next shift, and extended shifts require longer rest periods [source: FAA]. Flight attendants have similar shift restrictions [source: e-CFR, 91.1062].


If your flight has a delayed crew, there's a good chance you haven't yet boarded the plane. Whether in the building or on the tarmac, though, ask an airline representative to keep passengers informed about the status of the delay, including estimates of when the replacement crew will take over.

4: Security Threats

people at airport security checkpoint
Enforcing restrictions at checkpoints like this one helps airports deter security threats.

Security is a top priority in the air travel industry. The federal government, through its various agencies, has strict regulations about whom and what they allow beyond the airport security gates, out on the tarmac and on commercial airplanes.

Security personnel take extra precautions when threats seem imminent. This includes suspicious occurrences such as an unlabeled box found abandoned in the terminal or an unidentified person found roaming the tarmac. The airport could also be on high alert after a bomb threat.


Depending on the threat, extra security precautions might include grounding flights scheduled to depart or stranding arrivals on the tarmac rather than allowing them to approach a gate. In extreme cases, airlines might divert your flight to another airport or cancel the flight altogether before you take off.

One of the most dramatic impacts on flights due to security precautions occurred in September 2001. That month, which included the four-flight terrorist attack that shook the United States, airlines canceled 99,324 (20 percent) of their scheduled flights. This anomalous event impacted statistics (and travelers) dramatically that year, with twice as many flights canceled than in any of the nine years that followed. [source: RITA]

3: Mechanical Issues

jet engine detail
Mechanical issues in airplane parts (like this jet engine) may cause your flight to be delayed.

The Federal Aviation Administration (FAA) has stringent mechanical restrictions an airplane must meet. This includes strict standards on the operating condition of the airplane as well as required regular maintenance checks. Any deviation from normal operations on an airplane must be resolved before the plane can depart.

Repairs could take anywhere from a few minutes to several hours. If you've already boarded the plane, you may be forced to wait on board during the repair. This could be particularly annoying if the plane has to cut its power to make the repair, leaving you stuck inside without light, air movement or temperature control.


In extreme cases, the airline may be unable to complete the repair while you're waiting on the tarmac. In those cases, the airline will let passengers deplane and wait at the gate, especially to avoid federal fines for tarmac delays exceeding three hours [source: Stoller]. Sometimes, the airline cancels the flight and reschedules passengers for later flights. If you're stranded by these extended mechanical delays, be patient and courteous to the airline staff members. Keep in mind that they're probably as frustrated as you are about the situation. Cooperate with them on finding your best option to get going again.

2: High Traffic

An air traffic control tower at an airport
Too much highway traffic can make you late to work, and too much air traffic can delay your flight.

Airports can experience traffic congestion like busy highways during rush hour. If you're looking to avoid tarmac delays from heavy traffic, a closer look at the data can help you figured out the busiest days and times of day.

Airport data reveal that while holidays can be busy times, they aren't the busiest days of the year as you might expect. For example, according to an analysis of federal flight data from 2007, the most flights per day for Minneapolis-St. Paul International Airport (MSP) occurred on Thursdays and Fridays in June, during the month of July and around spring break. The most hectic days of November and December aren't even in the airport's top 100 busiest days [source: Welbes and Webster]. In the nation's busiest airport, Hartsfield-Jackson Atlanta International Airport (ATL), in an average week in September 2010, Thursdays were the most passenger-heavy days. The busiest times of day were between 5 and 6 a.m. and between 1 and 8 p.m. [source: CBT].


Even if the airport and airline are handling arrivals and departures efficiently, air traffic control (ATC) may be the bottleneck as it works to handle all the flight traffic and ensure safe routes. Just like traffic cops rerouting cars and trucks past an accident or road construction, air traffic controllers must reroute aircraft past bad weather, security threats or just an increased number of other planes in the same air space.

1: Weather

snow ploughs cleaning up airport
Snow ploughs work to clear snow from a gate area while planes wait.
Scott Olson/Getty Images

Though most commercial jets can operate on a rainy day, significant weather conditions produce some of the most notorious flight delays. In 2010, weather was the cause for delay or cancelation of 6.5 percent of domestic arrivals in the U.S. That's about one third of all the delays and cancelations for those flights [source: RITA].

Delays can vary based on the type of weather, the number of flights impacted and how well the airport is equipped to handle the situation. Thunderstorms and icy surfaces can stall flights for a few minutes or a couple of hours. De-icing equipment can cut that wait time in sub-freezing temperatures. Snow and the sustained winds of hurricanes can cause interruptions that are more extensive and often lead to canceled flights. This can attract a lot of media attention, too, such as when winter weather in the Midwest affected holiday plans for travelers nationwide during the high-traffic weeks of late December 2009 [source: Associated Press].


These top five reasons for tarmac delays cover most of the scenarios in which approximately 1 in 5 flights are unable to operate on time [source: RITA]. In many cases, no one reason stands alone: bad weather during a high traffic period multiplies the effect of each delay, as do security lock-downs that also prevent crews from assuming their duties on time. Since you can't always predict when these delays will happen or how long they will last, plan to have a book, music player or other preferred form of personal entertainment tucked in your carry-on bag to help you pass the time.

Fly forward to the next page for lots more information about air travel.

Lots More Information

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More Great Links

  • Associated Press. "Midwest Slammed by Snow, Ice on Christmas." CBS Interactive, Inc. Dec. 25, 2009. (Feb. 11, 2011)
  • Electronic Code of Federal Regulations (e-CFR). "Title 14: Aeronautics and Space, Part 91-General Operating and Flight Rules, Subpart K-Fractional Ownership Operations Program Management, Section 91.1059 Flight time limitations and rest requirements: One or two pilot crews." Feb. 3, 2011. (Feb. 6, 2011)
  • Electronic Code of Federal Regulations (e-CFR). "Title 14: Aeronautics and Space, Part 91-General Operating and Flight Rules, Subpart K-Fractional Ownership Operations Program Management, Section 91.1062 Duty Periods and rest requirements: Flight attendants." Feb. 3, 2011. (Feb. 6, 2011)
  • Federal Aviation Administration (FAA). "Fact Sheet-Pilot Flight Time, Rest, and Fatigue." Jan. 27, 2010. (Jan. 30, 2011)
  • Research and Innovative Technology Administration (RITA). "Airline On-Time Statistics and Delay Causes." U.S. Department of Transportation, Bureau of Transportation Statistics. (Jan. 30, 2011)
  • Stoller, Gary. "U.S. imposes 3-hour limit on tarmac delays." USA TODAY. Dec.22, 2009. (Jan. 30, 2011)
  • U.S. Customs and Border Protection (CBT). "CBT Airport Wait Times." (Feb. 9, 2011)
  • Welbes, John and MaryJo Webster. "Airport's busiest days don't fit 'common wisdom'; they'll come this month." Pioneer Press. Jan. 12, 2011. (Feb. 9, 2011)$20218