Month: February 2025

On January 29, a commercial flight collided with an Army helicopter over the Potomac River in Washington, DC, killing 67 people. Less than two months earlier, on December 12, 2024, the US Senate Committee on Commerce, Science, and Transportation held a “Subcommittee Hearing on U.S. Air Traffic Control Systems, Personnel and Safety.” The testimony offered at the hearing makes for grim reading, even if you didn’t know that a tragedy was around the corner.

For example, Kevin Warsh of the Government Accountability Office described a just-published report called “Air Traffic Control: Urgent FAA Actions Are Needed to Modernize Aging Systems.” Here’s a flavor of the report:

After a shutdown of the national airspace in 2023 due to an aging air traffic control (ATC) system outage, the Federal Aviation Administration (FAA) conducted an operational risk assessment to evaluate the sustainability of all ATC systems. The assessment determined that of FAA’s 138 systems, 51 (37 percent) were unsustainable and 54 (39 percent) were potentially unsustainable. Of the 105 unsustainable and potentially unsustainable systems, 58 (29 unsustainable and 29 potentially unsustainable systems) have critical operational impacts on the safety and efficiency of the national airspace … FAA had 64 ongoing investments aimed at modernizing 90 of the 105 unsustainable and potentially unsustainable systems; however, the agency has been slow to modernize the most critical and at-­risk systems. Specifically, when considering age, sustainability ratings, operational impact level, and expected date of modernization for each system, as of May 2024, FAA had 17 systems that were especially concerning. The investments intended to modernize these systems were not planned to be completed for at least 6 years. In some cases, they were not to be completed for at least 10 years. In addition, FAA did not have ongoing investments associated with four of these critical systems.

Or here’s a sample of commentary from Dean Iacopelli, Chief of Staff of the National Air Traffic Controllers Association:

FAA telecommunications are the backbone of the air traffic control system. The FAA needs extensive telecommunications services and networking capabilities to support the operation of the NAS [National Airspace System] and other agency functions. The FAA Telecommunications Infrastructure (FTI) program currently provides these services and networking capabilities through a service-based contract, in which the service provider continually updates the underlying technologies. The majority of FTI’s telecommunication lines function on an aging copper wire infrastructure, which is an outdated and no longer readily supported, as many local phone companies are discontinuing service to copper wire equipment throughout the country. As a result, air traffic controllers throughout the U.S. are experiencing a steady increase in unexpected outages of air traffic systems. Recent ground stops at airports in the New York and Washington, D.C., areas highlight the risks and consequences of telecommunication network failures. To date, there are over 30,000 services at over 4,600 FAA sites that must transition away from copper wire and onto a fiber optic cable network in order to avoid severe service disruptions and extensive flight delays. …

Even before the FAA’s telecommunications crisis, the FAA was working to mitigate the risks associated with its faltering Notice to Airmen (NOTAM) system, which has been the source of significant disruptions throughout the NAS. The NOTAM system is vital for sharing and disseminating safety-critical flight information between both air traffic controllers and pilots. However, in early 2023, a complete failure of the NOTAM system caused nationwide ground stop causing significant flight delays. … Much like the FAA’s looming telecommunications crisis, the NOTAM crisis was not at the top of any F&E [facilities and equipment] priority lists until after the 2023 collapse resulted in cascading nationwide delays and ground stops. …

Automation platforms such as ERAM and STARS deliver flight plan and surveillance information to air traffic controllers on a real-time basis. These platforms are the foundational systems that keep our NAS operating safely 24-hours a day, 7-days a week, 365-days a year. Over the past four years, air traffic levels have continued to grow at a rate of 6.2% per year post-COVID, excluding new entrant operations. Air traffic automation systems have components reaching end-of-life that need to be replaced. Due to historically flat F&E funding, as a result of the FAA requesting less than it needs to maintain the system, air traffic automation has been unable to meet the growing needs of the NAS reducing the efficiency of the system. In the near future, controllers will have to rely on this inadequate technology to maintain the safety and efficiency of the NAS.

Or here is one example from David Spero, representing the Professional Aviation Safety Specialists who “install, maintain, repair and certify the radar, navigation, communication and power equipment that comprises the U.S. National Airspace System (NAS).”

[T]he results of the survey [of PASS members] indicate top concerns are related to aging equipment, cumbersome procedures, parts that are unreliable or unavailable, system complexity, and staffing and training of the workforce. At the rapid pace with which technology changes, the FAA is getting further behind in replacing aging systems. … The biggest challenge is a lack of vision on behalf of the agency. The length of time it takes the FAA to implement new systems is directly related to the fact that current NAS systems and equipment are becoming obsolete. … For instance, many facilities are still relying on an aging communications technology known as Time Division Multiplexing (TDM). TDM is a method of combining multiple data streams into a single communication channel by allocating specific time slots for each data stream. Use of this antiquated technology is not only inefficient, but it is unnecessarily costly. Telecommunication companies now use carrier ethernet and are not required by the Federal Communications Commission to support TDM technology. … Unfortunately, the FAA is still relying on TDM and is being charged a premium by communications companies that no longer regularly use the technology.

There are many additional complaints. The underlying issue here may be a structural one: the FAA is the provider of air navigation services, but it is also responsible for overseeing its own performance. In addition, the FAA budget goes though a political process, so instead of deciding what needs to be done, raising the money, and doing it, the FAA is at the mercy of the budget churned out by Congressional committees. Marc Scribner, Senior Transportation Policy Analyst at the Reason Foundation, points out that many other countries have decided in recent decades that this model doesn’t work. Instead, these other countries set up the provider of air traffic navigation services as a separate company: sometimes government-owned, sometimes a nonprofit, sometimes a for-profit. The company is a separate financial entity: it has the power to charge fees to airlines and airplanes, and the power to sell bonds to raise capital if needed. The role of the government is then limited to overseeing this company. Scribner argues:

The United States was once the global leader in airspace management. However, in recent decades, we have fallen behind peer countries that have modernized their air traffic control practices and technologies. … The status-quo ANSP [air navigation services provider] model in the United States was historically the dominant model globally, whereby air traffic control was provided by a civil aviation authority within the transport ministry. That model has undergone major change since 1987 outside of the United States, starting when the government of New Zealand removed its air traffic control system from the transport ministry by restructuring it as Airways New Zealand, a self-supporting government corporation. Within 10 years, more than a dozen other countries had followed suit.

Separating the provision of air navigation services from the civil aviation authority and putting the ANSP at arm’s length from its safety regulator, like all the other key players in aviation—airlines, business aviation, general aviation, airframe manufacturers, engine producers, pilots, mechanics, and so forth—is now the globally recognized best practice. For more than two decades, this has been International Civil Aviation Organization (ICAO) policy. The United States is among the last industrialized countries that have not taken this step to eliminate the fundamental conflict of interest of having an aviation regulator also operate a service it is tasked with regulating.

The revenue source for ANSPs operated as public utilities is globally accepted cost-based user fees in accordance with the airport and air traffic control charging principles promulgated by ICAO. Prior to the conversion of these ANSPs to public utilities, those revenues were nearly always paid by airlines and other airspace users to the respective national governments. In most cases, once an ANSP has been converted to a utility, the user-fee revenue flows directly to the ANSP as its primary source of revenue. This makes it possible for the ANSPs to issue revenue bonds based on their projected revenue streams, just as airports do today in the United States and elsewhere. It is through their predictable streams of revenue that come directly from users that ANSPs outside the United States can successfully finance large-scale capital modernization efforts.

Globally, three ANSPs have been moved out of the government entirely under either an independent nonprofit user cooperative model or as partially privatized companies. Another 55 operate as wholly owned government corporations. Just 19—mostly developing countries, but also including the United States, Japan, and Singapore—operate as part of legacy civil aeronautics authorities that also regulate aviation safety. ANSPs that operate as public utilities funded by user fees now number 62 and serve 83 countries globally.

My understanding is that past efforts to reorganize the FAA on this alternative model have failed in Congress not because of opposition from large airlines, because of concerns from smaller airlines and those who fly smaller planes, who fear that running the FAA on user fees would increase their costs. Whatever the political reason, one would hope that the tragic mid-air collision over Washington could serve as a wake-up call. On this issue, it’s time to run over some special interests and create the organizational structure that will allow rapid modernization of America’s air traffic control systems.

The Survey of Adult Skills was carried out across 31 mainly high-income economies in 2003. It’s a survey that’s done by having actual interviewers meet people in their homes. For the US, the sample size was 3,765, which may not sound like much, but it’s worth remembering that a typical Gallup poll is only about 1,000 people.  As long as you remember that the results should be interpreted as plus-or-minus a few percentage points, you can can learn something from them.

The results of the survey were published by the OECD as “Do Adults Have the Skills They Need to Thrive in a Changing World? Survey of Adult Skills 2023” in December. Here, I’ll focus on putting some of the US results in context.

The survey focuses on three types of skills: numerary, literacy, and problem-solving. The skills tend to be correlated across categories: that is, if a country is good at one skill, it tend to be good at others. Here’s a figure showing numeracy and literacy scores. As you can see, the US falls well below average on numeracy scores, and slightly below average on literacy.

Perhaps more troubling is that within the US scores, the gap between the 90th and the 10th percentile is either widest, or close to widest, across countries. In other words, the US average score is made up of both exceptionally high-performing and low-performing scores. The bars in the figure show the gap between 90th and 10th percentile scores, and you can see the US bar graphs on the far left.

This matters. The world economy is evolving toward higher skills, which then can be combined with improved technology. A country in which adults are highly unequal in skills will be unequal in other ways as well. Here’s one more figure from the report, this one showing patterns of the tasks performed in US jobs over time. The intensify of “routine” tasks is falling. The intensity of “social” and “nonroutine analytical” tasks has generally been rising. Those who are only equipped for routine tasks are going to have a hard time in US job market.

I understand why the calendar adds an extra day to February every four years. The revolution of the earth around the sun is approximately 365 and one-quarter days. Every four years, that adds up to one additional day, plus some extra minutes. The modest rounding error in this calculation is offset by steps like dropping the extra day of leap year for years ending in “00.”

But my question is why February has only 28 days in other years. After all, January has 31 days and March has 31 days. If those two months each donated a day to February, then all three months could be 30 days long, three years out of four, and February could be 31 days in leap years. Every other month is either 30 or 31 days. Why does February only get 28 days?

(This post is republished, with minor changes, from February 29 a year ago.)

The answer to such questions leads to a digression back into the history of calendars. In this case, Jonathan Hogeback writing at the Britannica website tells me, it seems to settle on the Roman king Numa Pompilius back around 700 BCE, before the start of the Roman Empire. The ancient Roman calendar of that time had a flaw: it didn’t have nearly enough days. As Hogeback writes:

The Gregorian calendar’s oldest ancestor, the first Roman calendar, had a glaring difference in structure from its later variants: it consisted of 10 months rather than 12. In order to fully sync the calendar with the lunar year, the Roman king Numa Pompilius added January and February to the original 10 months. The previous calendar had had 6 months of 30 days and 4 months of 31, for a total of 304 days. However, Numa wanted to avoid having even numbers in his calendar, as Roman superstition at the time held that even numbers were unlucky. He subtracted a day from each of the 30-day months to make them 29. The lunar year consists of 355 days (354.367 to be exact, but calling it 354 would have made the whole year unlucky!), which meant that he now had 56 days left to work with. In the end, at least 1 month out of the 12 needed to contain an even number of days. This is because of simple mathematical fact: the sum of any even amount (12 months) of odd numbers will always equal an even number—and he wanted the total to be odd. So Numa chose February, a month that would be host to Roman rituals honoring the dead, as the unlucky month to consist of 28 days.

This discussion does explain why February would be singled out, since it was the month of rituals honoring the dead. In Numa’s calendar, the 355-day year would be made up of 11 months that had the lucky odd numbers of 29 or 31 days, plus unlucky February.

The discussion also explains why months that start with the prefix “Oct-” or eight, “Nov” or nine, and “Dec-” or ten, are actually months 10, 11, and 12 in the calendar. Those names were originally part of a 10-month calendar year.

But questions remains unanswered: Why did the Romans of that time view odd numbers as lucky, compared with unlucky even numbers? I suppose that explaining any superstition is hard, but I’ve never seen a great explanation. A Dartmouth course on “Geometry in Art and Architecture” describes Pythagorean feelings about odd and even numbers. For those of you keeping score at home, Pythagoras lived about two centuries after Numa Pompilius. The Dartmouth course material summarizes aspects of “Pythagorean Number Symbolism”:

Odd numbers were considered masculine; even numbers feminine because they are weaker than the odd. When divided they have, unlike the odd, nothing in the center. Further, the odds are the master, because odd + even always give odd. And two evens can never produce an odd, while two odds produce an even. Since the birth of a son was considered more fortunate than birth of a daughter, odd numbers became associated with good luck.

Various mentions of the luckiness of odd numbers recur over time. A few centuries later in the first century BCE, the poet Virgil has the character Alphesiboeus (a shepherd who sings about love rituals) say in Eklogue VIII (from the A.S. Kline translation):

Bring Daphnis home, my song, bring him home from town.

First I tie three threads, in three different colours, around you

and pass your image three times round these altars:

the god himself delights in uneven numbers.

Bring Daphnis home, my song, bring him home from town.

Or leaping ahead a millenium-and-a-half, at the start of Act V of the The Merry Wives of Windsor, Shakespeare has Falstaff say:

Prithee, no more prattling. Go. I’ll hold. This
is the third time; I hope good luck lies in odd numbers.
 Away, go. They say there is divinity in odd
 numbers, either in nativity, chance, or death.
Away.

While I acknowledge this history of a belief in odd numbers, as a person born on an even day of an even month in an even year, I’m not predisposed to accept it. But it’s interesting that modern photographers have a guideline for composing photographs called the “rule of odds.” Rick Ohnsman at the Digital Photography School, for example, describes it this way:

This is where the rule of odds comes into play, a deceptively simple yet powerful tool in your photographic arsenal. It’s all about arranging your subjects in odd numbers to craft compositions that are naturally more pleasing to the eye. Unlike more static guidelines, the rule of odds offers a blend of structure and organic flow, making your images both aesthetically pleasing and impressively compelling.

The revised calendar of Numa Pompilius couldn’t last. With only 355 days, it didn’t reflect the actual period of the earth revolving around the sun, and thus led to further revisions which are a story in themselves.

But when you think about it, the question of February having 28 days all goes back to Numa Pompilius and the superstitions about odd numbers. The modern calendar has 365 days in a typical year. You might think that the obvious way to divide this up would be to start off with 12 months of 30 days, and then add five days. Indeed, the ancient Egyptians had a calendar of this type, with five “epagomenal” or “outside the calendar days added each year.

The preference over the last two millennia, at least since the time of Julius Caesar, is to have 12 months, with a few of them being a day longer. But even so, why not in a typical year have five months of 31 days, and the rest with 30? The “problem,” I think, is that most months would then have unlucky totals of an even number of days. By holding February to 28 days rather than 30, you can redistribute two days from February and have 31 days in January and March. Thus, you can have only four months with an even total of 30 days every year (“Thirty days hath September, April, June, and November …”), and seven months always with the luckier odd total of 31 days. In leap years, when February has 29 days, then eight months have an odd number of days. I think this makes February 29 a lucky day?