The broken wing, the detached wheel, the broken undercarriage: twenty horror days, what's happening to United Airlines?

Wing pieces coming off in flight. A rear undercarriage wheel lost just after takeoff. Flames from the left engine, still immediately after takeoff. And a rear undercarriage that gave way, this time immediately after landing, Causing the aircraft to go off the runway..

The twenty days since last February 20 have been among the blackest in the recent history of United Airlines, which four times ended up in the media halfway around the world for incidents at once very serious and embarrassing for the company's image, which only luck would have it that they did not result in injuries or deaths.

The horror sequence began, in fact, on February 20. when, in the course of A transcontinental flight between San Francisco and Boston., the crew reported a 'slat issue' on the right wing, a slat problem, which are those 'ailerons' that are opened forward during takeoff and landing to increase aircraft lift at low speeds.

The 'issue' consisted in the fact that a good portion of the innermost slat had come off. As 'corroded,' it flew away. The crew preferred to abort the flight, making an emergency landing in Denver.

On Thursday, March 7, a Boeing 777-200ER just took off from San Francisco for Osaka. with 235 passengers on board, Literally lost a left rear undercarriage wheel seconds after coming off the ground. The incident was accidentally captured by a passerby with a cell phone and ended up not only on social media but also on all American TV.

The wheel, weighing several quintals, ended up in one of the airport employees' parking lots, destroying one car and damaging two others. Fortunately, there were no injuries. The B777 was 'diverted' to Los Angeles International, where it made an emergency landing without consequence.

Friday, March 8, was the blackest day of all: On social media, and then on U.S. TV, images, taken by some passengers, of the flames released from the left engine of a Boeing 737 that had just taken off from Houston and was bound for Fort Myers, Fla.. The aircraft turned around and landed a few minutes later in Houston.

Finally, on the same day and also in Houston, a Boeing 737 MAX 8 ended up off the runway in a meadow after its left rear undercarriage failed immediately after landing at the end of a flight from Memphis. Again, perhaps the most serious case of all, there were no consequences for the passengers and crew, who left the plane following emergency procedures.

One question is legitimate: what happens to United Airlines? As all the aircraft involved were Boeings, many American media took the opportunity to once again throw the cross on the American manufacturer, which since the MAX grounding five years ago has been under indictment for a series of serious accidents (the latest The one of the detached tailgate on an Alaska Airlines MAX 9 that just took off from Portland).

But, in truth, Boeing has little to do with the most recent incidents at United, which seem far more related to maintenance issues: what fault does Boeing have if a jet over 22 years old loses a wheel after takeoff? Or if another old one of even nearly 30 years old loses a wing piece in flight?

Evidently, two factors are at play in these cases, and none have to do with Boeing: the advanced age of the airplanes and the maintenance, which on older aircraft becomes increasingly challenging and expensive.

Delays in deliveries of new airplanes and a general tendency to keep their aircraft in service for longer periods than European airlines do and have always done are also to blame, the major U.S. carriers, American Airlines, United Airlines and Delta Airlines, find themselves with really old planes in service. Then again, they have huge fleets, approaching a thousand airplanes, renewing which means long lead times and billions of dollars.

Thus, for example, United finds itself with 61 Boeing 757s in service whose average age exceeds 25 years; that of the 767s, which also fly to Italy, even exceeds 26 years; but even more 'modern' planes such as the A320s it has in its fleet are more than 25 years old, on average, while the B777s are just over 20 years old (but with the oldest specimens nearing 30 years of service).

American, which has withdrawn all Boeing 767s and Boeing 757s from service, is in better shape, although its B777s are close to 20 years old on average and A320s are over 23 years old.

Delta, on the other hand, stands as if not worse than United, since the average age of its 65 Boeing 767s and 126 Boeing 757s exceeds 26 years, and its 61 A320s have been in service, on average, for even more than 28 years.

This is data worthy of third-world airlines, such as some from Africa or from countries like Afghanistan, Iran and other troubled places on the planet. Of course, there are those who say that with efficient maintenance a jet can fly safely even for 50 years. But then things like what we have seen in the last 20 days happen in the United house....

• B737
• B757
• B777