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.
24
questions
3
votes
1
answer
3k
views
How is the debris deflector on the DC-9-80 ("MD-80")'s nose gear kept from striking the ground during landing?
The DC-9-80 (marketed as the "MD-80") has, mounted to its nose gear, what I presume to be a debris deflector (a sled-shaped device to keep the nose gear from kicking up pieces of gravel or ...
- 27.5k
18
votes
1
answer
4k
views
Why is the DC-9-80 ("MD-80") prohibited from taking off with a flap setting between 13 and 15 degrees?
A bit of digging into the 7Z9363 accident investigation has brought up some interesting information regarding the DC-9-80 ("MD-80")'s flap system:
Flaps may be positioned in any of the six ...
- 27.5k
5
votes
1
answer
510
views
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 ...
- 27.5k
1
vote
1
answer
460
views
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....
- 27.5k
1
vote
2
answers
610
views
Can I act as SIC with these specific type ratings?
Can I act as SIC on a part 91 ferry flight, if I hold...
a DC-9 type rating and the flight is in an MD-80?
a B-737 type rating, can I act as SIC on a B-737NG?
3
votes
2
answers
452
views
Why do the DC-9’s three-phase electrical systems use separate, unconnected breakers for each phase?
Aircraft electrical systems use two types of electricity:
Direct current (DC),1 which always travels in the same direction (can be supplied directly from the aircraft’s battery, if necessary, but ...
- 27.5k
16
votes
7
answers
7k
views
Why was the DC-9-80/MD-80 so successful despite being obsolete almost from birth?
The McDonnell Douglas DC-9-80/MD-80 series of narrowbody jetliners was the second-to-last DC-9 major version produced (from 1979 through 1999), the second-largest, the most-produced (just under half ...
- 27.5k
3
votes
1
answer
342
views
What about the DC-9's wing makes wingletting it so difficult?
A common way of making older airliners more efficient without increasing their wingspan is to add winglets, either as a retrofit for existing aircraft or as a new, wingletted derivative of a ...
- 27.5k
1
vote
1
answer
168
views
How much do a DC-9's wings weigh?
How much do the wings weigh? How much does the landing gear weigh? How much fuel does it take to fill the tanks? We, at Confederation College are trying to donate a DC-9 for training purposes and ...
8
votes
1
answer
675
views
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 ...
- 27.5k
13
votes
4
answers
4k
views
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 ...
- 27.5k
0
votes
1
answer
112
views
Where can I find information on the DC-9's turn radius in flight?
Does anyone know where I can find information on a DC-9-30's turn radius at various altitudes and airspeeds? I've tried Googling it, but all I've found is information about its turn radius while ...
- 27.5k
1
vote
1
answer
761
views
What prevents DC-9 series aircraft from being reengined with more-efficient engines?
All DC-9s except for the MD-90\B717 series use old, inefficient Pratt & Whitney JT8D series low-bypass turbofans, even the best of which have a paltry 1.74:1 bypass ratio. We know that a DC-9 can ...
- 27.5k
7
votes
2
answers
945
views
What is the round thing on the tip of an MD-90 wing?
I like to pretend I know about airplanes, but have always wondered what the round things on the tip of MD-90 wings are. Here is an image of what I am talking about:
To be clear, my question is what ...
- 181
8
votes
2
answers
3k
views
Why is the empennage of some aircraft not placed on the centerline?
Check the MD80's empennage below.
Can easily tell it's not built on exactly centerline by naked eyes.
Is that because aluminum joint or consider aerodynamics?
I don't think it is manufacturing ...
- 125
1
vote
0
answers
165
views
What is the big hole at the bottom of the vertical stabilizer on the Boeing 717? [duplicate]
What is the big hole located on the forward vertical stabilizer's bottom used for?
(Image source)
- 957
12
votes
5
answers
13k
views
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 ...
user14897
13
votes
1
answer
1k
views
Why does the MD-87 have strakes on its engines?
Apparently, the MD-87 has a strake on both engines:
Source: Airliners.net
If I'm not wrong, the engine strake attaches the airflow at high angles of attack on the wing. But in this case the engine is ...
- 11.4k
3
votes
3
answers
803
views
MD81: Why are there so many lights on the fuselage?
Looking at this photo I can see lots of lights on the fuselage of this MD81. It can't be a reflection, can it?
Source: Airliners.net
Why are there so many lights?
- 11.4k
12
votes
1
answer
2k
views
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: Airliners.net
- 11.4k
10
votes
1
answer
2k
views
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 ...
- 30.9k
11
votes
2
answers
2k
views
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....
- 11.7k
14
votes
1
answer
3k
views
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 ...
- 14.6k
57
votes
1
answer
11k
views
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 ...
- 9,832