Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
Movable Control Surfaces On MD-90 Engine Pylons  
User currently offline2H4 From United States of America, joined Oct 2004, 8955 posts, RR: 59
Posted (8 years 11 months 1 week 1 day 20 hours ago) and read 12823 times:
AIRLINERS.NET CREW
DATABASE EDITOR




I ran across this photo:


View Large View Medium
Click here for bigger photo!

Photo © Brett B. Despain





...and the photographer mentions that the aft end of the engine pylons have movable control surfaces to aid in pitch control. Specifically, they provide additional nose-down pitch authority to prevent stalls from occuring.

Here are some close-ups:







This is the first I've heard of movable control surfaces on engine pylons. Further research revealed a previous thread on the topic.

Does anyone know if any other aircraft utilize such a system, or is it unique to the MD-90?


Thanks!




2H4





Intentionally Left Blank
37 replies: All unread, showing first 25:
 
User currently offlineAeroWeanie From United States of America, joined Dec 2004, 1609 posts, RR: 52
Reply 1, posted (8 years 11 months 1 week 1 day 18 hours ago) and read 12795 times:
Support Airliners.net - become a First Class Member!

Its unique to the MD-90...

User currently offlineHAWK21M From India, joined Jan 2001, 31684 posts, RR: 56
Reply 2, posted (8 years 11 months 1 week 1 day 13 hours ago) and read 12723 times:

Amazing.Things one learns of Everyday  bigthumbsup 
regds
MEL



Think of the brighter side!
User currently offlineBohica From United States of America, joined Feb 2004, 2701 posts, RR: 0
Reply 3, posted (8 years 11 months 1 week 1 day 13 hours ago) and read 12715 times:

Very interesting.
(filler)


User currently offlineBri2k1 From United States of America, joined Dec 2004, 988 posts, RR: 4
Reply 4, posted (8 years 11 months 1 week 1 day 12 hours ago) and read 12711 times:

You may or may not know, the MD-80, which flies using small servo tabs that deflect the larger control surfaces, has a built-in stall aversion system, as well. The elevator is the only primary control surface (I believe) which has the ability to be powered to the nose down position without requiring any airflow. The T-tail design begs for some stall recovery method, and on the -80, it's accomplished with a powered H-stab. On the -90, it appears to use engine thrust and smaller control surfaces to get out of the "deep stall."


Position and hold
User currently offlineAR1300 From Argentina, joined Feb 2005, 1740 posts, RR: 3
Reply 5, posted (8 years 11 months 1 week 1 day 12 hours ago) and read 12700 times:

Uhhh???I feel really ignorant now, I didn't get a darn word  crazy 

Again, please???

Thx, Mike



They don't call us Continental for nothing.
User currently offlineBri2k1 From United States of America, joined Dec 2004, 988 posts, RR: 4
Reply 6, posted (8 years 11 months 1 week 1 day 12 hours ago) and read 12699 times:

I'm not sure what you're asking!

A small plane might use a series of cables and linkage to move the control surfaces (ailerons, elevators, rudder, or some combination of those) to change the airplane's pitch, roll, and yaw.

A larger plane might be "fly-by-wire," where the control inputs are translated into electronic commands, carried out by hydraulic or electric actuators that move the control surfaces.

The MD-80 is somewhat unique in that instead of the above methods, it takes advantage of the air flying over the control surfaces to deflect them. Control inputs just move small "servo tabs" electrically. These tabs deflect into the airstream, forcing the control surface in the direction commanded.

However, the T-tail design can result in a "deep stall" where airflow to the elevator is blocked by the wings, making a nose-down pitch change (to recover from a stall) impossible. So, the MD-80 has the ability to electrically move the elevator to the nose-down position when the control wheel is pushed fully forward to the stops. This allows breaking the stall even when minimal airflow is present at the elevator.

The MD-90 accomplishes the same stall recovery by using the movable mini-elevators behind the engines.

I hope this answers the question I think you were asking!



Position and hold
User currently offlineAAR90 From United States of America, joined Jan 2000, 3474 posts, RR: 46
Reply 7, posted (8 years 11 months 1 week 1 day 10 hours ago) and read 12684 times:

Quoting Bri2k1 (Reply 6):
The MD-80 is somewhat unique in that instead of the above methods, it takes advantage of the air flying over the control surfaces to deflect them. Control inputs just move small "servo tabs" electrically. These tabs deflect into the airstream, forcing the control surface in the direction commanded.

Commonly referred to as McDonnell-Douglas' "cable-and-pulley" airplane, the MD's control inputs primarily move cables connected to small "control tabs" on the larger control surfaces. Moving these control tabs changes the local aerodynamics such that the pilot is "flying" the control surface in order to control the plane. Boeing calls it "manual reversion" (a backup mode of operating). MD drivers simply are flying in manual reversion mode all the time.

Quoting Bri2k1 (Reply 6):
However, the T-tail design can result in a "deep stall" where airflow to the elevator is blocked by the wings, making a nose-down pitch change (to recover from a stall) impossible. So, the MD-80 has the ability to electrically move the elevator to the nose-down position when the control wheel is pushed fully forward to the stops. This allows breaking the stall even when minimal airflow is present at the elevator.

Hydraulically powered (not electrically) when yoke is pushed near full forward position. In fact, it is the control tab position that actually commands the hydraulics to activate (yoke-to-cables-to-elevator control tab-extreme movement-mechanically activating elevator hydraulic actuators-moving entire elevator as a unit).

Quoting Bri2k1 (Reply 6):
The MD-90 accomplishes the same stall recovery by using the movable mini-elevators behind the engines.

The MD90's Pylon Flaps are in addition to everything the MD80 utilizes (i.e. they do not replace MD80 flight controls).



*NO CARRIER* -- A Naval Aviator's worst nightmare!
User currently offlineVikkyvik From United States of America, joined Jul 2003, 10027 posts, RR: 26
Reply 8, posted (8 years 11 months 1 week 1 day 8 hours ago) and read 12674 times:
Support Airliners.net - become a First Class Member!

Question:

If there's not enough airflow over the h-stab to enable aerodynamic control surface deflection, but you deflect the control surface hydraulically, how does this really affect the deep stall situation? The minimal airflow would need to create sufficient up-force on the h-stab. It just seems surprising that there's not enough airflow to deflect a control surface, but there's enough that once said control surface is deflected, the resulting force will pitch the nose down.

Maybe I'm missing something.

Thanks guys.

~Vik



"Two and a Half Men" was filmed in front of a live ostrich.
User currently offlineATLAMT From United States of America, joined Sep 2001, 240 posts, RR: 3
Reply 9, posted (8 years 11 months 1 week 1 day 3 hours ago) and read 12622 times:

Quoting Vikkyvik (Reply 8):



Quoting Vikkyvik (Reply 8):
Question:

If there's not enough airflow over the h-stab to enable aerodynamic control surface deflection, but you deflect the control surface hydraulically, how does this really affect the deep stall situation? The minimal airflow would need to create sufficient up-force on the h-stab. It just seems surprising that there's not enough airflow to deflect a control surface, but there's enough that once said control surface is deflected, the resulting force will pitch the nose down.

Basically in a deep stall the airflow over the elevator is reduced and or blocked due to the angle of attack, leaving you unable to control the elevator with the servo tabs. The servo tabs need air flowing over them to work. The hydraulic assist will help you get the nose down and air flowing over the horiz. stab. so the servo tabs once again work.



Fwd to MCO and Placard
User currently offlineVC-10 From United Kingdom, joined Oct 1999, 3701 posts, RR: 34
Reply 10, posted (8 years 11 months 1 week 1 day 3 hours ago) and read 12614 times:
Support Airliners.net - become a First Class Member!

Quoting Bri2k1 (Reply 6):

The MD-80 is somewhat unique in that instead of the above methods, it takes advantage of the air flying over the control surfaces to deflect them. Control inputs just move small "servo tabs" electrically.

The BAC One-Eleven had that system way back in 1962 but it was deleted and PFC's installed after a couple of accidents (in test flying) where it was found that the sluggish response of the elevators at low speed was a contributery factor.

Are you sure the Servo Tabs are electric? The One-Eleven's were cable/rod driven by the control column


User currently offlineAAR90 From United States of America, joined Jan 2000, 3474 posts, RR: 46
Reply 11, posted (8 years 11 months 1 week 1 day 1 hour ago) and read 12585 times:

Quoting Vikkyvik (Reply 8):
If there's not enough airflow over the h-stab to enable aerodynamic control surface deflection, but you deflect the control surface hydraulically, how does this really affect the deep stall situation? The minimal airflow would need to create sufficient up-force on the h-stab. It just seems surprising that there's not enough airflow to deflect a control surface, but there's enough that once said control surface is deflected, the resulting force will pitch the nose down.

The pilot moves the (relatively small) control tab.... the control tab changes the local aerodynamics such that there will be enough local aerodynamic force for the free-floating control surface to move... the change in control surface position changes aerodynamics that pitch (roll or yaw) the entire plane. Hence the phrase: "the pilot flys the control surface." At slow speeds there may not be enough airflow over the control tab to create enough local aerodynamic force to move the control surface, but due to the much larger size if the control surface, if it were to move it could still create enough aerodynamic force to change the pitch (roll or yaw) of the entire plane.
To provide for that possibility, MD designed the MD80 elevator with a hydraulic assist system at large nose-down control column inputs. With the yoke pushed near its forward limit, the control tab is deflected near its limit and it mechanically activates the elevator hydraulic system. The hydraulic actuators directly move the elevators in the nose-down direction and will maintain that pressure until the yoke (and therefore control tab) position is reduced. All mechanical, nothing electrical.
The MD90 is another stretching of the DC9 airframe and one of the methods MD incorporated to assist in recovery from potential stall was to add the pylon flaps (they only work for nose-down commanded movements). In all my time flying the -90 I never once felt them so I have no idea how effective they may/may not be. They were just..... there.  Wink



*NO CARRIER* -- A Naval Aviator's worst nightmare!
User currently offlineVikkyvik From United States of America, joined Jul 2003, 10027 posts, RR: 26
Reply 12, posted (8 years 11 months 1 week 19 hours ago) and read 12487 times:
Support Airliners.net - become a First Class Member!

Gotcha, thanks AAR90. That is definitely a cool form of control surface deflection. Actually, maybe that explains why on a recent takeoff on an AA MD-80, the ailerons were deflected on both sides until we were moving along at a good pace on the takeoff roll. I was wondering about that.

~Vik



"Two and a Half Men" was filmed in front of a live ostrich.
User currently offline474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9
Reply 13, posted (8 years 11 months 1 week 15 hours ago) and read 12433 times:

What moves this "control surface" on the aft end of the pylon?

Does it have its own hydraulic actuator?

How is it connected to the yokes, cables?

Does it only move up from the faired position?

You would think with the boundary layer as thick as it is on the aft portion of an aircraft these two small surfaces would have almost no effect.


User currently offlineHAWK21M From India, joined Jan 2001, 31684 posts, RR: 56
Reply 14, posted (8 years 11 months 1 week 9 hours ago) and read 12389 times:


Any Sketch on the Details of the Duct on the Undersurface illustrated above.
regds
MEL



Think of the brighter side!
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17039 posts, RR: 66
Reply 15, posted (8 years 11 months 1 week 4 hours ago) and read 12380 times:

Quoting 474218 (Reply 13):
Does it only move up from the faired position?

My guess is that it would only move down. Moving up would not force the nose down.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineBuyantUkhaa From Mongolia, joined May 2004, 2899 posts, RR: 3
Reply 16, posted (8 years 8 months 1 week 6 days 23 hours ago) and read 11543 times:

The tab system is alsoused on the BAe-146/ARJ series, I saw on another thread.


I scratch my head, therefore I am.
User currently offlineNonfirm From United States of America, joined Sep 2005, 434 posts, RR: 0
Reply 17, posted (8 years 8 months 1 week 6 days 6 hours ago) and read 11409 times:

When we were getting ready to replace the MD-80 with the MD-90 we asked about the tab on the pylon and we were told that they were placed there due to the increased size of the pylon and would help with stall recovery and they would deflect on their own when needed but since we never received the a/c I do not know if this is correct.

User currently offlineHAWK21M From India, joined Jan 2001, 31684 posts, RR: 56
Reply 18, posted (8 years 8 months 1 week 5 days 12 hours ago) and read 11301 times:

Quoting Nonfirm (Reply 17):
When we were getting ready to replace the MD-80 with the MD-90



Quoting Nonfirm (Reply 17):
since we never received the a/c

What replaced your MD80s.
regds
MEL



Think of the brighter side!
User currently offlineNonfirm From United States of America, joined Sep 2005, 434 posts, RR: 0
Reply 19, posted (8 years 8 months 1 week 5 days 11 hours ago) and read 11296 times:

Quoting HAWK21M (Reply 18):
What replaced your MD80s.
regds
MEL

we replaced the MD-90 order with the 737-400 this was back in 1993 to 1994 time frame.


User currently offlineYYZYYT From Canada, joined Apr 2005, 955 posts, RR: 0
Reply 20, posted (8 years 8 months 1 week 3 days ago) and read 11139 times:

Quoting AAR90 (Reply 11):
The pilot moves the (relatively small) control tab.... the control tab changes the local aerodynamics such that there will be enough local aerodynamic force for the free-floating control surface to move... the change in control surface position changes aerodynamics that pitch (roll or yaw) the entire plane. Hence the phrase: "the pilot flys the control surface." At slow speeds there may not be enough airflow over the control tab to create enough local aerodynamic force to move the control surface, but due to the much larger size if the control surface, if it were to move it could still create enough aerodynamic force to change the pitch (roll or yaw) of the entire plane.

Well, that sounds ingenious, but I'm still usure of one thing:

Let us take an elevator for example. If the pilot needs the elevator up*, a control tab will open to change the aerodynamics to raise the elevator... for example a small flap deflecting down to create pressure that "flies" the elvator up. But when the elevator starts to rise, would not the pressure from the airflow stop the movement? Isn't the whole point of control surfaces to create pressure by changing airflow? In other words, how does the control tab overcome the greater resistance of the (presumably) larger control surface? Or am I missing something?

Anyone who works on MD products / has an aeronautical engineering degree care to help?

YYZYYT

* or does he/she press the button and wait for the doors to open?


User currently offlineAAR90 From United States of America, joined Jan 2000, 3474 posts, RR: 46
Reply 21, posted (8 years 8 months 1 week 2 days 16 hours ago) and read 11063 times:

YYZYYT,
I don't have a real simple/neat way of describing it. Here's one fellow's attempt:
http://pilotfriend.com/flight_traini.../aerodynamics/primary_controls.htm

Tab Control Systems
In the early days of large aircraft many designers avoided the need to provide boosted controls, as described above, by using tab activated controls. The DC-9 for example uses tab actuated controls. In a tab controlled system the pilot moves only a small actuating tab on the larger control surface. The force generated by the tab then moves the main control. This is of course the same way trim tabs work. Therefore, you can think of this system as being like trim tabs if they were connected to the control wheel instead of a separate control wheel. Note that in a tab controlled system there is no direct connection between the control column and the control surface.


For me (a non-engineer) I think of it simply as force and leverage. The control TAB has leverage on the control surface (hinged to it). Move the control TAB and you push/pull on the moveable control surface (elevator in this case). Since the elevator is moveable, the control tab has no leverage to move the entire airframe. OTOH, the moveable control surface is hinged to the airframe and has leverage over it. Move the control surface and the airframe will move. It is simply a matter of how you make the control surface move.... direct cable/pully connection, hydraulic power, or control TAB, etc.



*NO CARRIER* -- A Naval Aviator's worst nightmare!
User currently offline2H4 From United States of America, joined Oct 2004, 8955 posts, RR: 59
Reply 22, posted (4 years 4 months 3 weeks 2 days 10 hours ago) and read 8213 times:
AIRLINERS.NET CREW
DATABASE EDITOR

Quoting AAR90 (Reply 7):
Hydraulically powered (not electrically) when yoke is pushed near full forward position.

Ok, apologies for resurrecting such an old thread, but might any of you have the means to acquire photos of the pylon control surfaces in the deflected position?



Intentionally Left Blank
User currently offlineDH106 From United Kingdom, joined Jun 2005, 626 posts, RR: 1
Reply 23, posted (4 years 4 months 3 weeks 2 days 9 hours ago) and read 8191 times:

Quoting YYZYYT (Reply 20):
In other words, how does the control tab overcome the greater resistance of the (presumably) larger control surface? Or am I missing something?

The tab is on the trailing edge of the surface & this gives it a much larger moment arm about the surface hinge than the surface itself. The parent surface may also be aerodynamically 'balanced' and be relatively force neutral to the airflow by having it's hinge point placed some distance behind it's leading edge. These together allow the relatively small tab to 'fly' the elevator.



...I watched c-beams glitter in the dark near the Tanhauser Gate....
User currently offlinePGNCS From United States of America, joined Apr 2007, 2825 posts, RR: 45
Reply 24, posted (4 years 4 months 3 weeks 2 days 7 hours ago) and read 8099 times:

Quoting Bri2k1 (Reply 4):
You may or may not know, the MD-80, which flies using small servo tabs that deflect the larger control surfaces, has a built-in stall aversion system, as well. The elevator is the only primary control surface (I believe) which has the ability to be powered to the nose down position without requiring any airflow. The T-tail design begs for some stall recovery method, and on the -80, it's accomplished with a powered H-stab. On the -90, it appears to use engine thrust and smaller control surfaces to get out of the "deep stall."

All DC-9's and MD-80/90 have unpowered ailerons (hydraulically powered spoilers assist in roll control), a hydraulically powered rudder (aerodynamic tabs for backup), and DC-9/MD-80's have tab-controlled elevators with hydraulic assist in the nose down direction (to help with stall recovery). The MD-90 has a full time hydraulically-powered elevator, with aerodynamic tabs as a backup. All of these aircraft have an electrically powered trimmable horizantal stabilizer which is used by pilots and by the autopilot to keep the aircraft in trim. The MD-90 also has "pylon flaps," control surfaces that deflect downward, which are hydraulically powered, on the aft of the engine pylon.

Quoting Bri2k1 (Reply 6):
The MD-80 is somewhat unique in that instead of the above methods, it takes advantage of the air flying over the control surfaces to deflect them. Control inputs just move small "servo tabs" electrically. These tabs deflect into the airstream, forcing the control surface in the direction commanded.

The tabs have no electrical actuators; they are manually connected to the control columns via cables and pulleys.

Quoting Bri2k1 (Reply 6):
However, the T-tail design can result in a "deep stall" where airflow to the elevator is blocked by the wings, making a nose-down pitch change (to recover from a stall) impossible. So, the MD-80 has the ability to electrically move the elevator to the nose-down position when the control wheel is pushed fully forward to the stops. This allows breaking the stall even when minimal airflow is present at the elevator.

The MD-80 as well as the rest of the family ALWAYS has the ability to move the elevator, but never electrically. You CAN move the trimmable horizontal stabilizer electrically with the trim switches (and the autopilot can too), but this is unrelated to stall recovery. There is a stick pusher system installed as part of the extensive stall warning protections to move the yoke forward as a stall prevention feature, but the yoke is what still moves the elevators.

Quoting AAR90 (Reply 7):
Hydraulically powered (not electrically) when yoke is pushed near full forward position. In fact, it is the control tab position that actually commands the hydraulics to activate (yoke-to-cables-to-elevator control tab-extreme movement-mechanically activating elevator hydraulic actuators-moving entire elevator as a unit).

   Exactly. Very concisely said, AAR.

Quoting AAR90 (Reply 7):
The MD90's Pylon Flaps are in addition to everything the MD80 utilizes (i.e. they do not replace MD80 flight controls).

  

Quoting VC-10 (Reply 10):
Are you sure the Servo Tabs are electric?

Good observation VC-10, they are not.

Quoting AAR90 (Reply 11):
The pilot moves the (relatively small) control tab.... the control tab changes the local aerodynamics such that there will be enough local aerodynamic force for the free-floating control surface to move... the change in control surface position changes aerodynamics that pitch (roll or yaw) the entire plane. Hence the phrase: "the pilot flys the control surface." At slow speeds there may not be enough airflow over the control tab to create enough local aerodynamic force to move the control surface, but due to the much larger size if the control surface, if it were to move it could still create enough aerodynamic force to change the pitch (roll or yaw) of the entire plane.
To provide for that possibility, MD designed the MD80 elevator with a hydraulic assist system at large nose-down control column inputs. With the yoke pushed near its forward limit, the control tab is deflected near its limit and it mechanically activates the elevator hydraulic system. The hydraulic actuators directly move the elevators in the nose-down direction and will maintain that pressure until the yoke (and therefore control tab) position is reduced. All mechanical, nothing electrical.

   Brilliantly said. There's nothing more to add.

Quoting AAR90 (Reply 11):
In all my time flying the -90 I never once felt them so I have no idea how effective they may/may not be. They were just..... there.

   Neither have I and I never want to feel them, either!  
Quoting Vikkyvik (Reply 12):
Actually, maybe that explains why on a recent takeoff on an AA MD-80, the ailerons were deflected on both sides until we were moving along at a good pace on the takeoff roll. I was wondering about that.

The ailerons can be at any position during ground operations; they will be opposite each other as they are bussed together, but wind can push them to any position; they will quickly streamline with airflow over the wing during takeoff roll. Likewise the elevators can be in any position on an MD-80 or DC-9 and they are NOT bussed together, so they can be deflected in opposite positions (this won't be a factor on the MD-90); not to fear they will streamline quickly on the takeoff roll as well.

Quoting 474218 (Reply 13):
What moves this "control surface" on the aft end of the pylon?

Does it have its own hydraulic actuator?

Yes it does.

Quoting 474218 (Reply 13):
Does it only move up from the faired position?



It only moves down from the faired position in an effort to lower the nose (to break a stall).


25 LMP737 : I've told this story before but I have a somewhat interesting story about those hydraulically powered elevators. Years ago I was lubing the horizonta
26 Post contains links wn700driver : >Quoting Vikkyvik (Reply 12):Gotcha, thanks AAR90. That is definitely a cool form of control surface deflection. Actually, maybe that explains why
27 Post contains images PGNCS : Glad you stayed out of the way! The yoke jumps powerfully in the cockpit too when the pumps are turned on, and the rudder pedals can kick quite a bit
28 musang : I hope not! Manual reversion in a Boeing (I speak for the 737 Classic) is when all hydraulics to the flight controls are lost and is a major inconven
29 PGNCS : What AAR90 is getting at is that the aerodynamic tabs control the ailerons and elevators on all DC-9 and MD-80's (though MD-90's have powered elevato
30 Fabo : How does it go about spoilers? And since rudder is inop, would it not end up, if spoilers were too inop, in a slip-like situation? (Sorry, I learnt t
31 musang : Hello PGNCS - agreed. I was just pointing out that "manual reversion" is a term referring to the total hydraulic loss scenario so isn't really appropr
32 AAR90 : Not an official term used in MD aircraft; however, it provides an apt description of the way the DC9 series operates. I had a little trouble understa
33 musang : Indeed. "Reversion" implies that it has reverted from something else, i.e. from hydraulic drive in the Boeing case, to unassisted cable drive. I agree
34 Post contains images 2H4 : Stressful job?
35 musang : Right! I guess someone discovered it by accident and word got around. Actually the more I think about it, there was a mass damper weight in the first
36 PGNCS : I agree with you. I was trying to explain that AAR90 was getting at the conceptual way the system functions, not that someting is wrong with the DC-9
37 Post contains images LMP737 : So was I, while the days off would have been nice I'd rather skip the head injury/truama. [Edited 2010-05-06 19:51:10]
Top Of Page
Forum Index

Reply To This Topic Movable Control Surfaces On MD-90 Engine Pylons
Username:
No username? Sign up now!
Password: 


Forgot Password? Be reminded.
Remember me on this computer (uses cookies)
  • Tech/Ops related posts only!
  • Not Tech/Ops related? Use the other forums
  • No adverts of any kind. This includes web pages.
  • No hostile language or criticizing of others.
  • Do not post copyright protected material.
  • Use relevant and describing topics.
  • Check if your post already been discussed.
  • Check your spelling!
  • DETAILED RULES
Add Images Add SmiliesPosting Help

Please check your spelling (press "Check Spelling" above)


Similar topics:More similar topics...
Control Surfaces On The Wing posted Tue Sep 16 2003 18:35:39 by DIJKKIJK
Damaged Engine Intake On MD-11 posted Sat Jan 29 2005 00:21:38 by Singel09
MD90 Engine Pylons Control Pitch Too? posted Wed Jun 30 2004 20:29:08 by Fly2HMO
Double Engine Failure On MD-82 At FL330..Why? posted Fri Jul 19 2002 21:02:08 by Mr Spaceman
Why Fabric Control Surfaces? posted Wed Nov 1 2006 03:38:16 by 3DPlanes
What Point Control Surfaces Ineffective posted Fri Aug 4 2006 22:17:25 by Sean1234
Speed Brakes On MD-88. What Did I See? posted Thu Apr 27 2006 17:25:32 by Mastropiero
Aux Turbo On JT3-C6 Engine? posted Thu Apr 27 2006 04:52:40 by Tg 747-300
Why Does The Front-wheel Door Not Close On MD-11? posted Fri Apr 21 2006 00:14:33 by Aero145
Any MD-80 Engine Retrofits? posted Wed Mar 29 2006 04:18:58 by L1329II

Sponsor Message:
Printer friendly format