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Questions tagged [dc-9-family]

A twin-engine, T-tail, regional to medium-range jet airliner produced from 1965 until 2006, first by Douglas, followed by McDonnell Douglas, and then, finally, by Boeing.

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57 votes
1 answer

Why does the DC-9 have engines that are angled slightly upwards?

As per subject, I see that the above mentioned aircraft and some others that have engines mounted on the rear of the fuselage, have the engine intakes tilted slightly upwards. Why has this solution ...
Fabrizio Mazzoni's user avatar
11 votes
2 answers

Does the MD-80 seat layout affect the balance of the aircraft?

The MD-80 family has a 2-3 seat layout as seen in this image: Does the layout have any influence on the balance of the aircraft and if so what is used to balance out the weight? Image from seatguru....
SMS von der Tann's user avatar
13 votes
4 answers

Why does the DC-9-80/MD-80 have this cusp in its fuselage?

The fuselage of the McDonnell Douglas DC-9-80 (also known as the "MD-80") has a pronounced cusp at floor level, as can be seen in this diagram (courtesy of Boeing, eater of McDonnell Douglas - at ...
Vikki's user avatar
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12 votes
1 answer

What is this hole on the tail of an MD-88?

There's a little hole on the leading edge of the vertical stabilizer of this plane: What is that? What is its purpose? Thanks Source:
user13197's user avatar
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5 votes
1 answer

Does the MD-90 use a different elevator system from the other DC-9 versions?

While reading the 7Z9363 (a 2017 DC-9-80 [“MD-80”] very-high-speed rejected takeoff and runway overrun resulting from an undetectable wind-induced elevator jam that rendered the aircraft unable to ...
Vikki's user avatar
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16 votes
1 answer

Why is the MD-80 magnetic compass behind the first officer's seat?

I was watching this video about the MD-83 magnetic compass and I found it interesting that it's designed the way it is. I'm not sure which of the airplanes in this series featured this strange ...
ryan1618's user avatar
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12 votes
5 answers

Why do airliners have "pressure bulkheads"?

Image source: FAA What part of the fuselage aft of the bulkhead would leak pressure? Or is it just there to reduce stresses? How does a DC-9/MD-80/90 incorporate aft bulkheads when there's a ...
user avatar
10 votes
1 answer

Was this a successful deployment of an MD-88 tail cone evacuation slide?

In this video, the tail cone is popped off as part of the evacuation. It stays attached on a lanyard which seems to be more of a hazard than letting it fall free. Additionally, the slide doesn't ...
Simon's user avatar
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8 votes
1 answer

Did the DC-9 ever use RATO in revenue service?

While reading the NTSB report on the crash of ALM Flight 980, I came across this interesting tidbit: ... The fuel charts used for the study made allowance for a higher consumption rate than the ...
Vikki's user avatar
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1 vote
1 answer

Why does the DC-9's antiskid system have to be manually disarmed during landing rollout following a ground-shift-mechanism malfunction on takeoff?

An aircraft's ground-shift mechanism (usually a sensor wired to the nosegear strut that looks to see whether the strut is compressed or not) tells the aircraft whether it's on the ground or in the air....
Vikki's user avatar
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