Southwest Airlines flight 1380: What happens when a large hole is ripped in the side of a plane

We’re sorry, this feature is currently unavailable. We’re working to restore it. Please try again later.

Advertisement

This was published 5 years ago

Southwest Airlines flight 1380: What happens when a large hole is ripped in the side of a plane

Updated
A Southwest Airlines plane sits on the runway at the Philadelphia International Airport after it made an emergency landing in Philadelphia.

A Southwest Airlines plane sits on the runway at the Philadelphia International Airport after it made an emergency landing in Philadelphia.Credit: AP

Reports following a passenger who was almost sucked out of a smashed plane window on an airliner in the US conjures up images from a popular movie scenario.

One person died in the incident on board a Southwest Airlines Boeing 737 from New York to Dallas. Shrapnel shattered a window and the cabin depressurised, after one of the plane's engines exploded. The plane made an emergency landing in Philadelphia.

In previous incidents, people have been sucked to their deaths following sudden large fuselage ruptures, but the size of the hole matters. The movie idea that a bullet shot through a plane's skin could be catastrophic has been widely rubbished.

Passenger Marty Martinez filmed a Facebook Live video on board a Southwest Airlines flight that made an emergency landing at Philadelphia airport on April 17, 2018.

Passenger Marty Martinez filmed a Facebook Live video on board a Southwest Airlines flight that made an emergency landing at Philadelphia airport on April 17, 2018.Credit: Facebook/Marty Martinez

In contrast, a gaping hole in United Airlines flight 811 - flying from Los Angeles to Sydney, with stopovers in Honolulu and Auckland - in February 1989 led to the deaths of nine passengers, including New Zealander Lee Campbell. The plane returned to Honolulu.

According to the US National Transportation Safety Board (NTSB), the probable cause of the disaster was the sudden opening of a forward cargo door and subsequent explosive decompression. The opening of the door - attributed to a faulty switch or wiring in the door control system - caused extensive damage to the fuselage and cabin structure next to the door.

Kevin and Susan Campbell went to Honolulu and began an investigation independently of the NTSB in the aftermath of their son's death.

It turned out Boeing had known about potential problems with the cargo doors on 747s for some time. As early as 1975, it was realised that the locking mechanism wasn't up to the job, and airlines were asked to fit double locks.

The damaged engine on the Southwest Airlines plane being inspected at Philadelphia International Airport .

Advertisement

Also on board the plane was Bev Thomas from Hawke's Bay, New Zealand. Talking about the disaster quarter of a century later she said there had been a sudden, loud hissing noise, followed by an "almighty thud", about 20 minutes into the flight.

There was an incredible noise of rushing air and the cabin filled with some kind of fog. "All the lining inside was starting to rip apart. All the overhead baggage was spilling out". A flight attendant told her oxygen masks weren't needed because the plane wasn't high enough.

A cargo door flaw was also to blame for what, at the time, was the deadliest plane crash in history. Turkish Airlines flight 981 from Istanbul to London crashed outside Paris in March 1974. All 346 people on board died.

The crash was caused when an improperly secured cargo door at the rear of the plane broke off, causing an explosive decompression which severed cables necessary to control the aircraft, the Wikipedia entry said.

The Smithsonian Institution's Air & Space magazine explained that the air on an airliner is pressurised by the engines. Turbofan (jet) engines compress intake air with a series of vaned rotors right behind the fan. At each stage of compression, the air gets hotter, and at the point where the heat and pressure are highest, some air is diverted, some going to the cabin.

It's a bit of a complicated trip, but that air ends up cooled and mixed with air from the cabin. To maintain pressure in the cabin equal to that at low altitude, incoming air is held in the cabin by opening and closing an outflow valve, which releases incoming air at a rate regulated by pressure sensors.

"If the door blew off a jet at altitude, all the air in the cabin would depart very quickly and a momentary thick fog would envelope the cabin as the water vapor in the air condensed instantly," Air & Space said.

"Loose articles would fly around and foam rubber would burst as the tiny air bubbles within it expanded. Within a couple of seconds, oxygen masks would drop down from the overhead panels, and you would have to pull yours toward you and place it over your mouth and nose."

Passengers needn't worry about bullets causing decompression. "The airplane already has a huge hole in it called the outflow valve."

Professional pilot and international aviation training consultant David Lombardo made a similar point in his book Advanced Aircraft Systems. "A bullet hole in a cabin wall would have no perceived effect on cabin pressure…. A bullet hole is far smaller than the opening of the outflow valve. In fact, such a hole would account for less air leakage than what is normally lost around door and window seals."

Lombardo did point out that one problem with a largish hole could be a drop in cabin temperature from 21 degrees Celsius to -50C. "With temperatures that low, it is only a matter of seconds before hypothermia sets in and everyone begins to freeze to death."

TV series Mythbusters also did an episode showing nothing much happened when a bullet was fired through the fuselage of a pressurised aircraft. Obviously the plane was on the ground at the time.

Airline pilot, blogger and author Patrick Smith wrote in a column in Salon in 2006, that large scale structural failures, which could be disastrous, were "extremely rare". With a small breach, once cabin pressure had escaped, it could be reasonably assumed a plane would stay in one solid piece and fly fine.

Another Air & Space article referred to a US Federal Aviation Administration chart, which showed that at 43,000 feet crew members were able to perform flight duties with an insufficient supply of oxygen for a mere five seconds, "Hardly long enough to don an oxygen mask." But at 22,000 feet, passengers and crew would have five minutes of "useful consciousness" after rapid decompression.

In another incident last November, the windscreen on an Air New Zealand flight from Hokitika to Christchurch began cracking mid-flight, forcing the plane to drop altitude suddenly.

In Hawaii in 1988, cracks caused part of the roof of an Aloha Airlines Boeing 737 to peel open while the jet flew from Hilo to Honolulu. A flight attendant was sucked out of the plane and plunged to her death, and dozens of passengers were injured.

Eight people died in 2000 when the Beechcraft Kir Air 200 they were flying in lost cabin oxygen on a flight from Perth destined for Leonora in Western Australia. The plane kept going for about five hours before crashing when fuel ran out. The Australian Transport Safety Bureau report found the pilot and passengers were probably overcome by hypoxia, or oxygen starvation, after the plane's pressurisation system failed.

The accident was similar to the 1999 crash that killed US Open golf champion Payne Stewart and companions. Sudden high-altitude decompression after a blow out in the Learjet 35 was one theory put forward to explain the crash.

In 2005 Alaska Airlines flight 536 was forced to turn back to Seattle 20 minutes after takeoff when a crease in the side of the aircraft became a 30-by-15 centimetre hole, causing the cabin to lose pressure. Fortunately the MD-80 plane was quickly stabilised and landed safely. An investigation found the crease had been caused by baggage handlers who had bumped the fuselage with loading equipment.

Stuff.co.nz

Sign up for the Traveller newsletter

The latest travel news, tips and inspiration delivered to your inbox. Sign up now.

Most viewed on Traveller

Loading