21
votes
Accepted
What is this strake near the nose of the MD-80 for?
TLDR:
They are there to improve directional stability.
At high angles of attack, the wake from the fuselage covers the rudder, reducing yaw authority. Strakes mitigate this effect and thereby improve ...
- 8,272
16
votes
Accepted
Why does the DC-9-80/MD-80 have this cusp in its fuselage?
It's not a stress concentrator; it's just the opposite. What you're missing is that the floor itself at the pinched part forms a tension bridge that allows a more or less 'ovalized' circle while ...
- 136k
10
votes
What is this strake near the nose of the MD-80 for?
The nose strakes on the DC9-50 and subsequent models are to energise the airflow around the fuselage at high angles of attack.
Without the strakes, at high angles of attack, the turbulent flow around ...
- 84.5k
8
votes
How to find the remaining fuel without electrical power on the MD-80?
The normal Digital Fuel Quantity Display in the flight deck does not work without AC power, meaning you need to have either the APU running or external AC power connected:
Fuel Tank Quantity ...
- 58.3k
8
votes
Why does enabling engine sync on the MD-80 series trigger the "Master Caution" light?
AFAIK The reason you aren't supposed to take off/land with prop or engine sync on is because if the leader engine fails, the follower engine will reduce power to match it, and that is really not ideal,...
- 2,500
6
votes
What is ATR Automatic Thrust Restoration in MD-83?
The MD-80 series has two systems that can increase thrust in case an engine fails during takeoff:
Automatic Reserve Thrust (ART)
This system is independent of the throttle position and can increase ...
- 58.3k
6
votes
Why does the DC-9-80/MD-80 have this cusp in its fuselage?
To add to John's answer, why did they do it? To make more room in the passenger area.
It is important to remember that, opposite a submarine, pressure is higher on the inside of the aircraft in ...
- 21.3k
5
votes
Why does the DC-9-80/MD-80 have this cusp in its fuselage?
This is called the "double bubble". The 737 has a similar but less pronounced design.
Both aircraft had a primary requirement to seat a specific number of passengers in each row: 5 in the DC-9 and ...
- 51
3
votes
Why does the DC-9-80/MD-80 have this cusp in its fuselage?
The answer is soap bubbles:
They are filled with slightly higher pressure air, and when they're attached to each other, they have a planar "reinforcement-like" part between them. (see the picture)
...
- 131
3
votes
Why will windshear inop illuminate after landing in an MD-83?
The WINDSHEAR INOP light tells the pilots that the Predictive Windshear System cannot work:
System Annunciator Lights
[...]
An amber WINDSHEAR INOP annunciator is installed on the ...
- 58.3k
2
votes
Can I act as SIC with these specific type ratings?
The single B-737 type rating includes all variants of it, from the -100 through the Max; if you were typed in a -200, you have the type, so there is nothing else required in that regard to be Second ...
- 53.6k
1
vote
Why couldn't the co-pilot reach the rudder on Alaska Airlines 261?
The MD-80 uses a mechanical linked flight control system according to this article. This means, that aerodynamic forces of the control surfaces are transmitted directly to the control column. This can ...
- 5,044
1
vote
How is the due date for landing gear replacement determined?
To my knowledge, all lifed components are tracked from installed date. That is from personal experience, but I can certainly have a look through the regs to find an official source, if you require.
- 379
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