Know The Purpose Of This Hook? Here Are Some Secret Aircraft Features That Keep Your Life Safe

The aircraft are enormous flying machines that were just a fantasy about a century ago. When the first human flight was made possible by the Wright brothers, it was not considered the safest mode of transport, for all the right reasons. The airplane technology has evolved so much over the years that airplanes bigger than football fields are taking to the skies. The safety of air travel has been improved so much that it is now considered a mode of transport even safer than cars or trains. Apart from the major flight systems, the airplanes have tiny features to improve safety, that mostly go unnoticed.

Even if you are a frequent traveler, you may have missed out on the little details like the black triangles on overhead lockers or the yellow hooks on the wings. We have gathered some of these to let you know what their actual purpose is.

Wing Hooks

Most aircraft have little hooks on their wings to be used in case of an evacuation. A safety rope passes through the hooks from the door that helps the passengers walk out over the wing in the event of a water landing. The same are used to secure the life rafts and help steady the passengers as they make their way over the wing to the raft.



What could an ax be doing on an airplane unless there is a sneaky serial killer onboard? Well, carrying a little safety ax on all flight decks is mandated by the Federal Aviation Administration. A retired airline captain explains the purpose: “It is a fire fighting device used to cut away cockpit panels and other aircraft areas if a fire develops inside them. The cutting allows the fire to be exposed making it easier to aim the extinguishers to kill the fire off.”

Murals Fantastic

Exit Door Handles

Why would no need handles on the side of the emergency exit door? In the case of an emergency evacuation, passengers are panicked enough that they could disregard anyone around while trying to flee the plane. In the hassle, the aircraft crew that is manning the exit doors could be pushed out by the perturbed passengers. The handles allow the crew to hold on in such an event.


Black Triangles

May triangles have small black triangles on the walls that identify the position from where the wings are most visible. The crew can determine the location easily in case they need to check on the wings before take-off. Pilot Bruno Gilissen explains the purpose saying, “If there’s any doubt about the position of the slats or flaps, the pilot can walk down the cabin, have a look through the window where the triangle is located, and see the numbers written on the slats/flaps.”

The Gate

Cooper Vanes

Technical faults are not the only problem you will come across in an airplane. A little device by the name Cooper vane prevents the back stairwell of the plane from opening midflight. The airstairs are usually used by passengers to board in rural airports.


A famous plane hijacker who referred to himself as DB Cooper used these stairs to escape a Boeing 727 using a parachute while it flew over Oregon. The preventive device is named after him, but since most planes do not have airstairs anymore, the device is rare.

Window Holes

Ever noticed the little pin prick holes in the window glass or airplanes? Yeah, that is not something to worry about as they serve to protect you. The pressure inside the plane is to be maintained so that the passengers are comfortable, but it is not easy for a single layer of glass to handle the pressure differential between the insides of the plane and the atmosphere. The three-layered glass of the window prevents itself from shattering on the inside with the help of this tiny hole. Read more on how the hole regulates the cabin pressure.

Why Do Plane Windows Have Holes

Auxiliary Power Unit and Ram Air Turbine

The Auxiliary power unit (APU) on an airplane mainly serves to start the craft’s main engine, but it also powers the electrical systems before the take-off and after landing. This includes the air conditioning and the lighting onboard. In the event of an engine failure, the APU provides emergency electrical power and when everything fails, comes in the Ram Air Turbine (RAT) that pops out of the bottom and generates electricity from the air stream.

Boeing 777 APU (via YouTube)


You are not allowed to smoke aboard an airplane, but honestly, who will stop you from smoking in the bathroom? The airlines do not trust the passengers at all, so they have installed ashtrays as a safety measure, just in case a passenger decides to break the rules.

Stuck At The Airport

1 Comment

  1. Fabio Rogerio Matiuzzi Reply

    Yes, Wright brothers invented the Hang Gliding. The first airplane, with an engine on it, was first invented by Santos Dumont.

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