>>There must be right this minute, people lined up at
>>some airport , waiting to board an MD80, who are
>>totally oblivious that this airplane is a death trap.
The DC9 aircraft (MD80/90 are marketing names for different models of the DC9) is not a death trap. It is very reliable and very forgiving. Virtually all flight controls are simple cable+pulley setups with no fancy computers or hydraulics to cause problems.
>>Is there something that a professional pilot can
>>tell us which will make our fears groundless.
I've stayed out of this fray because so little is known about what _really_ went on that everything is speculation at this point.
>>TELL US, would you let your loved ones fly
>>on the MD80?
Yes, without the slightest hesitation.
>>Or is this just a sad and tragic thing that happened
>>to just one airplane?
Most probably a single incident due to the simplicity of the flight control systems involved.
>>But please, from all of you professionals,
>>lets hear from you. TELL US. Peter.
Ok Peter, but understand conclusions are based upon speculation and not upon facts. There are few facts known at this time.
MD80/90 Stabilizer Trim is accomplished using one of two electric trim motors that turn a simple screwjack raising or lowering the leading edge of the Horizontal Stabilizer. High speed trim is the normal mode used by pilots (control wheel thumb switches) and moves the stabilizer at the blazingly fast speed of 1/3 degree per second. Slow speed trim is normally used by the autopilot and moves the stabilizer at an astounding 1/10 degree per second. Pilots also have switches on center pedestal to control that trim motor as well.
There is a Stabilizer Trim Switch (red guarded) on the center pedestal that when uncovered permits the pilots to flip the switch and stop the high speed motor from operating. That switch position is appropriately labeled: "STOP."
Behind the Captain's seat (within easy reach using your left hand) are three circuit breakers that remove all electrical power to the high speed electric trim motor and controls. Took me about 4-5 seconds to find and pull all three in the sim during multiple failure simulation Thursday.
Behind the Captain's left shoulder (again within easy reach using left hand) are three circuit breakers that remove all electric power to slow speed trim motor and circuits. Took me about 2 seconds to find and pull these.
So what do you do when one or the other system fails? Disconnect all electrical power to that system and use the other system. What if neither system operates? Disconnect all electrical power to both systems and continue to fly the aircraft manually.
How? Pilot control yoke is cable/pulley system to "control tabs" on the trailing edge of the elevators (trailing edge of horizontal stabilizer). Pilot moves yoke which moves control tabs which changes aerodynamics along elevator moving the elevator which changes aircraft pitch attitude. Essentially the pilot flys the elevator to the position desired. Very simple, very reliable system.
In the Alaska Air mishap the flight was an hour into the flight. What do you think was flying the aircraft: pilot (high speed trim) or autopilot (low speed trim)? Most probably the autopilot hence the slow speed trim motor is the problem. Pull the three CB's and the problem is solved. If not, your normal trim motor (high speed) is three times faster and stronger than the slow speed motor so just "override" what the slow speed motor is trying to do using normal trim switches.
If it was a high speed motor failure, you flip the trim switch to STOP (takes about 1/2 second) and pull the three CB's to that motor (another 4-5 seconds) then use alternate trim (slow speed motor) to retrim as desired.
Ultimately, the worst case situation is when none of the above works and you end up with full nose up or full nose down trim condition (motors can't go any further). Aircraft is still flyable, but only at higher airspeeds. Remember, you fly the elevator to where you need it so you need airspeed to get enough aerodynamic forces to move it where you want it. Nose up situation is relatively easy since you can more easily use leg muscles to assist holding (pushing) the control column forward. Full nose down is much more difficult since its mostly arm/wrist muscles at work (must be why trim problems are flown in the sim the day prior to 48's --2 days off--). Either way, it is possible --although not easy-- to land the aircraft. First did this 12 years ago as an FO and just 2 days ago as CA. My wrists are still a little sore, but it can be done.
Note: Long distance press photos of AA MD80 at PHX show horizontal stabilizer in full nose up trim condition. Yes it was a short-circuit in co-pilot trim switches.
The only thing scary to me about the Alaska Air mishap is that it appears to have been caused by the pilots trying to do too much with a broken airplane. By that I mean that if you've got an aircraft with control problems and you've got enough control that one of you (pilots) has the time to radio your maintenance base asking about CB's (remember, its a mechanical cable/pulley flight control system), then you've got enough control at that point in time to land the aircraft as is. Never mess with putting power back on a broken system if the system is not _required_ for flight.
My speculation on Wed. morning was that the pilots messed up (ouch, that hurts) or Alaska's procedures are messed up (that hurts more) or there was much more going on that hasn't been revealed as of yet. To date (Fri.evening) all information released so far further supports that position. )-;
The DC9/MD80/MD90 aircraft itself does not appear to have a safety related design flaw.
AA CA MD90
*NO CARRIER* -- A Naval Aviator's worst nightmare!