September 6, 2012

MD82 or MD83...Differences Training

I took these pictures over about a thirty minute period earlier this week on a flight from DFW to CMH (Columbus Ohio).  We were flying toward the darkness, so night came fast.  This was the last of five legs and our only venture out of the state of Texas for the day.  A keen eye might notice that this MD80 looks different than most.

Were you able to pick out any of the differences?  Notably, the center stack of engine instruments and ACARS interface?  There are some other minor differences, but these pictures aren't detailed enough to highlight them (iPhone pics by the way). This aircraft, N9420D is an MD83.  Originally delivered to British West Indies Airways  (BWIA) as 9Y-THU in December 1988, then operated by Trans World Airlines (TWA) as N9420D From December 1996 until December 2001, when it entered service with American Airlines under the same registration.  Most of the "MD80's" flown by American are actually MD82's...technically speaking, DC9-82's.  From a distance, it's hard to tell them apart.

The most notable differences between an MD82 and an MD83 are found in the limitations section of the Operating Manual which I've snipped and re-printed below.  With a ramp and taxi weight bump of approximately 10,000 pounds, the MD83 is a much more useful aircraft for long flights.  

You might be surprised to know that we rarely get anywhere close to the maximum structural takeoff weight of the aircraft, even when completely full.  And when we do, it is usually the added weight of fuel, not passengers and cargo, that becomes a limiting factor.  So the added payload capability of an MD83 becomes most useful when additional fuel is needed for long flights or when poor weather necessitates a destination alternate.  

Most MD83's have two auxiliary fuel tanks which this aircraft does not have.  Again, it's difficult to see in the pictures, but most MD83's have a slightly different fuel panel and four extra fuel pump switches.  Two fuel pumps in each of the two extra tanks.  Oddly enough, the auxiliary fuel tanks take up space under the cabin floor in the main fuselage and encroach on cargo space.  So...we can load up on fuel, but we may "bulk out" on cargo and could be forced to leave something behind.  I'm not sure this was a well thought out design. 

As you might imagine, the extra fuel comes in handy for long flights like DFW to SEA or ORD to SAN which are often well over 4 hours in length.  On any given day, an MD80 on the ground at SEA, PDX or SAN is almost surely an MD83.

Difference Training...

I am often asked if I exclusively fly one type aircraft, or if I am able to move from jet to jet.  Due to the vast differences between most airliners and the tremendous cost involved with training a pilot to fly a new type of equipment, pilots are almost always trained to fly one jet at a time.  I currently fly the MD80, but not all our MD80's are the same.

Most airlines train their pilots to fly the most common aircraft in a bid status, then spend a short amount of time on difference training.  When I was initially trained on the MD80, we spent all our time learning the MD82, then spent about a day going over the differences between the MD82 and the MD83. I still have my notes from that day and possess fewer than ten pages on the subject. 

The same goes for other aircraft types.  For instance, most airlines include the B757 and the B767 in the same bid status.  From the outside, most could not tell the difference between an MD82 and an MD83, but few would confuse a B757 with a B767.  The two jets look quite different and are significantly different in size.  But from the cockpit, and the closer to the instrument panel you are, the two are almost identical.

I'll leave you with one more picture.  See if you can tell the difference.  MD82 or MD83?


  1. Cool stuff, thanks for pointing out the diffs! I did notice right away that your 1st few cockpits are actually in the "21st Century"--very few steam gauges! NO offense, but when I think of MD-80's I think "dinosaur", LOL!

    That's the great thing about the Airbus. It was designed to make Differences training a nonevent. Even the A321, which is slightly diff. in design from the 320-318, is almost nada :-)

  2. Feel free to laugh. The 80 is a dinosaur!!! Nice thing about the old girl is that if you have one engine running...everything works! No computers, no fly-by-wire, its all manual and it all works.

    I considered writing a section about that...Airbus is leading the way when it comes to commonality between types. I tried but failed to reference an article I read a while back that claimed the upgrade time from the A320 to an A340 is like two weeks. Amazing!

    1. Once upon a time, on my honeymoon, we were invited up to the cockpit of the Air Tahiti Nui A340 (yes, PRE-9/11, lol!) I was amazed at how familiar it looked...just roomier, and 4 thrust levers instead of 2!

  3. Not being familiar with the MD-80 (i only flew on one as a pax once - very quiet towards the front, btw), I have to say that that panel looks like a kid got a box with all the instruments and was asked to put them together... It took me like 2 minutes to make sense of an airbus panel and probably 5 for a 737 - that is, recognizing the instruments and what they do, not that i'd be ready to fly said planes after 2 or 5 minutes :)
    Then came your panel... Ok, I saw the main instruments and engine gauges, but I'm left with a bunch of other gauges and instruments and i have no idea what they are. Oh, well :)

    Back to the question, the last photo should be of an md-82, which is a little older than the 83, thus the steam gauges instead of the electronic displays.

  4. Thanks for reading to the end AND answering the question.

    When I checked out on the MD80 they told us that the cockpit was "logically" laid out. They told us that engineers sat in a mock-up and put instruments exactly where the average person would on and so forth. Well, I've been on the beast for almost 13 years and I still struggle to find often unused instruments. It seems very illogical to me...but it's what I'm stuck with!

    Regarding the picture, you missed the mark, but I admit the picture is deceiving. That's actually an MD83. The engine instruments did come out on some of the newer jets, but they are not what determines whether a jet is an 82 or an 83. If you look closely in the picture, you will find the AUX Fuel Panel, which only exists on the 83, and there are four fuel extra fuel pump switches on the fuel panel.

    Thanks for your response!

  5. @capnaux. The only plane, in my view, that really looks like a dinosaur is the A380. It's unaesthetic, unweildy and ugly.