47

There is a little door on the upper deck above the cockpit: KLM 747

Source: Airliners.net, (modified to indicate location of hatch).

What is that door? What is its purpose?

kevin
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user13197
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1 Answers1

75

It's an emergency escape hatch. There are inertial reels in the cockpit ceiling adjacent to the hatch to allow the cockpit crew to exit the airplane. See this link for an account of their use escaping the aircraft during a hijacking.

There were five reels in the 747-100/200 aircraft. The cockpit had five seats: pilot, co-pilot, flight engineer, and two observer seats.

It's also sometimes used in third world countries to send a guy out to clean the cockpit windshield. In Mumbai I once made the mistake of asking the windshield to be cleaned, thinking, of course, they'd do it with a cherry picker. Much to my surprise, bare feet appeared at the top of the windshield followed by this poor fellow who was maneuvering into place to clean the windshield. He had a rope tied around his waist, but had he fallen it would have been bad because the rope was anchored through the hatch, which meant he would have swung badly had he fallen.

Terry
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    Nitpick: the aircraft in the picture is a 747-400 and has a cockpit crew of two, not three. The article you linked is 30 years old and describes a 747-100. – Nate Eldredge Mar 07 '16 at 04:21
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    @NateEldredge Whislt the minimum cockpit crew for a 747-400 is two, it is very common to have three people on longer flights. Even on shorter flights KLM often has a junior "co-co-pilot" on the 747. – DeltaLima Mar 07 '16 at 08:34
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    Or a instructor on a checkflight – ratchet freak Mar 07 '16 at 10:28
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    https://www.youtube.com/watch?v=2y5lNVbBeiU – RedGrittyBrick Mar 07 '16 at 11:12
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    @Terry - any thoughts why they used an overhead hatch on the 747 instead of the sliding window as in smaller Boeings? – Ralph J Mar 07 '16 at 14:38
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    @RalphJ I don't know why they went to the overhead hatch instead of the sliding windows. The only thing I can think of is that having decided to use inertial reels instead of the simple strap (as I remember at least) for the windows, they lacked room adjacent to the windows for the inertial reel storage. I came to the 747 from the 727, which had the sliding windows. I remember thinking I'd miss being able to open the window, but I didn't. – Terry Mar 07 '16 at 19:24
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    It took me several minutes of horrified contemplation before I realized that this hatch was only meant to be used while the plane was not in motion. – Crashworks Mar 08 '16 at 00:24
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    @Crashworks: This whole thing reminds me of those heart-stopping videos on YouTube featuring idiots changing the tyres on a car while it's being driven. – Lightness Races in Orbit Mar 08 '16 at 00:34
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    @Terry, just curious how your first notice of the windshield washer would have been his bare feet on the window. Wouldn't you notice people in the cockpit, opening the hatch and crawling out? Is the hatch access not directly in the cockpit? – FreeMan Mar 08 '16 at 15:36
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    @FreeMan This was a freighter sitting on the cargo ramp at Mumbai, then called Bombay. Freighters had the cockpit door removed so the cockpit and the upper deck were one area. Behind me there was typically lots of activity what with the loadmaster and ground personnel finalizing paperwork. Also, it was not uncommon for the f.e. to open the escape hatch, which was basically opposite him, to get more airflow. This guy backed down over the windshield from the top, so the first I saw of him was the bottoms of his bare feet at the top of the windshield. It was a different world back then. – Terry Mar 08 '16 at 16:27
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    @Terry - got it. That makes a lot more sense now. And thanks again for sharing your stories - they're great! – FreeMan Mar 08 '16 at 17:26
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    @Porcupine911: And I was trying to explain why they'd have a guy crawl out that hatch with a squeegee, even though the plane has wipers. (Probably, anyway - I've never owned a 747, so I have no first-hand knowedge :-)) – jamesqf Mar 09 '16 at 04:47
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    @jamesqf 747-100/200s do have wipers, but they're not like car wipers that have a squirt and clean function. All they do is wipe, and as I remember there was a prohibition against use on a dry windshield. The only times I ever used them was in extremely heavy precipitation on short final. Most of time, actually almost all of the time, the airflow over the windshield was more than sufficient for precipitation removal. In ten years on the 747, I think I used the wipers less then ten times. – Terry Mar 09 '16 at 09:18
  • @RedGrittyBrick: That is some very upbeat music for a video showing how to evacuate an aircraft's flightcrew in an emergency. – Vikki Oct 16 '19 at 03:00