#n984tw

[sentinelchicken]

The McDonnell Douglas MD-80 retains much of the hydraulic system architecture of the legacy DC-9 variants but with new and larger components as needed reflecting the fact that the MD-80 is nearly twice as heavy as the first DC-9 variants. ⁣ ⁣ The MD-80 has two separate and independent hydraulic systems- fluid from one system doesn’t mix with the other. They are designated “Left” and “Right”- the Left system is driven by a engine-driven variable displacement pump on the left engine and the Right system is driven by the same type of pump on the right engine. In addition, the right engine also drives an electric auxiliary pump based on that used on the DC-10. ⁣ ⁣ The engine hydraulic pumps have three settings- OFF, HIGH, and LOW. The HIGH pressurizes the hydraulic system to 3000 psi with all pumps including auxiliary pumps on. This is the setting used during takeoff and landing. The LOW setting is used during cruise with only the two engine pumps running at 1500 psi. Running at a lower pressure in cruise flight reduces wear and tear on the hydraulic components.⁣ ⁣ While the control surfaces like the elevators are cable driven for simplicity and reliability, stall recovery involves a hydraulic power boost to the tailplane control surfaces from the Left system. To prevent inadvertent activation of the stall recovery power boost, two different control valves in series have to be opened to allow hydraulic fluid to flow to the power boost actuators. ⁣ ⁣ #Avgeek #aviation #aircraft #planeporn #KDFW #DFW #dfwavgeek #airport #planespotting #airlines #McDonnellDougas #MD80 #American #AmericanAirlines #N984TW #instagramaviation #splendid_transport #instaaviation #aviationlovers #aviationphotography #flight #AvGeeksAero #AvgeekSchoolofKnowledge #AvGeekNation #TeamAvGeek #MD80Sunset (at DFW Airport) https://www.instagram.com/p/B3yHlvQhzN_/?igshid=1hg5rx5bjg2i

[sentinelchicken]

Everyone, from us avgeeks to passengers to American’s employees, knew this was a special day in the history of the airline if not in the history of the MD-80 program. Here’s a ramper getting a shot of the ship number of N984TW, “4YU” before its departure. ⁣ ⁣ I’ve always been fascinated with ship numbers, I suppose it’s a bit of a hold over in nautical traditions that crossed over into aviation, particularly in the days of the flying boats in the 1930s- just look at Pan American, they had a very nautical theme in their history, right down to their radio call sign “Clipper”. For airlines, ship numbers are an easier way to keep track of aircraft internally than using the tail number. Some airlines have systems where certain ship number groups can delineate certain aircraft subtypes or cabin configurations. For example, United Airlines years ago on its A320s, ship numbers in the 47xx block were overwater equipped, versus A320s in the 46xx block were not. Not sure if they still follow that system now, though. ⁣ ⁣ MD-80s at American Airlines with alphanumeric ship numbers 4xx, like this one being “4YU”, are ex-TWA. Legacy American MD-80s have a three digit ship number derived from the tail number (for the most part), like N501AA would be Ship 501. ⁣ ⁣⁣⁣ #Avgeek #aviation #aircraft #planeporn #KDFW #DFW #dfwavgeek #airport #planespotting #airlines #McDonnellDougas #MD80 #American #AmericanAirlines #N984TW #instagramaviation #splendid_transport #instaaviation #aviationlovers #aviationphotography #flight #AvGeeksAero #AvgeekSchoolofKnowledge #AvGeekNation #TeamAvGeek #MD80Sunset (at Dallas/Fort Worth Intl Airport (DFW)) https://www.instagram.com/p/B2AzSmhhxcJ/?igshid=8ojx3l5v2qgd

[sentinelchicken]

On the McDonnell Douglas MD-80 (as well as the legacy DC-9), the elevators are actually free floating and only receive a hydraulic boost with the control column pushed nose down more than 10 degrees. All all other times, the elevator free floats and is actuated by servo tabs connected by cables to the control column. ⁣ ⁣ To move the elevator nose down, the servo tab deflects up which moves the elevator down and to move the elevator nose up, the servo tab deflects down which moves the elevator up. When the MD-80/DC-9 is parked, the elevators tend to deflect upward because they are slightly weighted to be nose down. ⁣ ⁣ If the elevators were weighted more nose up, there would be more flutter coming from the tail surfaces during cruise flight. Since the elevators are free-floating, they are also not mechanically linked so in some wind conditions, a parked MD-80/DC-9 may have one elevator deflected upward more than the other side or even one up and one down. ⁣ ⁣ The aircraft in the foreground is N984TW, the last MD-80 built as “The Spirit of Long Beach” when it was delivered to TWA in 1999. That’s the aircraft that flew the last American Airlines passenger MD-80 services today as AA80 DFW-ORD. The other MD-80 is N982TW which left just before AA80 and was headed to Roswell for storage. ⁣ ⁣ #Avgeek #aviation #aircraft #planeporn #KDFW #DFW #dfwavgeek #airport #planespotting #airlines #McDonnellDougas #MD80 #American #AmericanAirlines #N984TW #N982TW #instagramaviation #splendid_transport #instaaviation #aviationlovers #aviationphotography #flight #AvGeeksAero #AvgeekSchoolofKnowledge #AvGeekNation #TeamAvGeek #MD80Sunset (at Dallas/Fort Worth Intl Airport (DFW)) https://www.instagram.com/p/B2AGu9Hh3nr/?igshid=u2h9f4c2qyzs

[sentinelchicken]

On the Douglas DC-9, the thrust reverser buckets when deployed were vertical- top bucket in line with the bottom bucket. This became problematic with some airlines as the lower bucket’s thrust efflux would kick up all sorts of FOD that could get sucked into the engine. ⁣ ⁣ Air Canada had a fleet of DC-9-10s and DC-9-30s and came up with a fix by angling the lower bucket out 17 degrees which toed in the upper bucket when reverse thrust was selected. Anything kicked up by the lower bucket was blown out to the side away from the engine intake. Many other airlines picked up Air Canada’s modification and McDonnell Douglas introduced the 17 degree rotation of the reverser buckets as production standard beginning with the Series 50. Any Series 30 aircraft built after the start if Series 50 production also had this fix as factory standard. ⁣ ⁣ So for example, all DC-9-34s have it fresh from the factory, but not all DC-9-33s did. ⁣ ⁣ When the MD-80 came along, that angled out reverser buckets was kept despite the newer engines as seen on N984TW- note the fairings for the thrust reverser actuator arms aren’t exactly horizontal with each other. Interestingly, despite all new engines and nacelles, the Boeing 717 (which I will insist on still referring to an MD-95 at times. Or most of the time, LOL) also has the same angled out reversers!⁣ ⁣ #Avgeek #aviation #aircraft #planeporn #KDFW #DFW #dfwavgeek #airport #planespotting #airlines #McDonnellDougas #MD80 #American #AmericanAirlines #N984TW #instagramaviation #splendid_transport #instaaviation #aviationlovers #aviationphotography #flight #AvGeeksAero #AvgeekSchoolofKnowledge #AvGeekNation #TeamAvGeek #MD80Sunset (at DFW Airport) https://www.instagram.com/p/B2iS9cgBToS/?igshid=f4v3zodhl71q

[sentinelchicken]

N984TW gets some final preparations before its departure as the last American Airlines MD-80 passenger revenue flight as American Flight 80 to Chicago O’Hare. It’s supremely apropos that a former TWA jet flies the ceremonial final MD-80 revenue services for American Airlines.⁣ ⁣ This particular MD-80 is very special as it is the very last MD-80 built at McDonnell Douglas’s Long Beach plant. It was an enormously successful aircraft for the company with 1191 MD-80s being built- when this last aircraft was delivered to TWA in 1999, it was in a special ceremony and christened “The Spirit of Long Beach” by then Mayor of Long Beach, Beverly O’Neill, in honor of the men and women who built the MD-80s from 1979 to 1999.⁣ ⁣ TWA’s head, Captain William Compton said at the delivery ceremony "This day is especially historic because TWA has now come full circle. Ironically, not only is TWA taking delivery of the last MD-80 twin-engine jet to be made by the former McDonnell Douglas work force, but in 1933, TWA took delivery of the first twin-engine transport airplane, the DC-1, made by a predecessor of McDonnell Douglas, the Douglas Aircraft Company. TWA's DC-1 was the only one of its kind ever made.”⁣ ⁣ The one and only DC-1 for TWA led to the improved DC-2 and that led to the iconic Douglas DC-3. That launched Douglas Aircraft to become one of the world’s premier commercial airframe builders as it moved into the jet age with the DC-8 and the MD-80’s predecessor, the DC-9. In fact, the MD-80 is an evolutionary development of the legacy DC-9 twin jet. ⁣ ⁣ When this last MD-80 was delivered to TWA in 1999, McDonnell Douglas was already a part of Boeing, having been acquired in 1997. ⁣ ⁣ While American Flight 80 on that day may have flown in American Airlines’ classic bare metal colors, it also flew on the wings of the storied 71-year history of Trans World Airlines. ⁣ ⁣ #Avgeek #aviation #aircraft #planeporn #KDFW #DFW #dfwavgeek #airport #planespotting #airlines #McDonnellDougas #MD80 #American #AmericanAirlines #N984TW #instagramaviation #splendid_transport #instaaviation #aviationlovers #aviationphotography #flight #AvGeeksAero #AvgeekSchoolofKnowledge #AvGeekNation (at Dallas/Fort Worth Intl Airport (DFW)) https://www.instagram.com/p/B2ILi8chb3Z/?igshid=z5ehei2qhoyd

[sentinelchicken]

The status board at Gate C2 at DFW this morning before AA80’s departure on the final American Airlines MD-80 revenue services to Chicago O’Hare. ⁣ ⁣ You couldn’t have picked a better city pair for the last revenue services for American’s MD-80s. Dallas/Fort Worth and Chicago O’Hare are the major American Airlines hubs they are today thanks to the massive expansion the jets allowed in the mid to late 1980s. ⁣ ⁣ Robert Crandall initially wanted to the MD-80 as a 727 replacement- but the operating economics were so good compared to the older jets that American Airlines could expand tremendously. The MD-80s allowed a 1/3 increase in seat capacity without incurring heavy overhead costs and that growth made American what it is today. Before the MD-80s arrived, there were only 244 jets in American’s fleet. Today there are 966 or so- obviously those aren’t MD-80s, but the growth facilitated by the MD-80s in American’s fleet allowed it to grown and need progressively newer aircraft, opening the door for the 757 and later the 737-800s. ⁣ ⁣⁣ #Avgeek #aviation #aircraft #planeporn #KDFW #DFW #dfwavgeek #airport #planespotting #airlines #McDonnellDougas #MD80 #American #AmericanAirlines #N984TW #instagramaviation #splendid_transport #instaaviation #aviationlovers #aviationphotography #flight #AvGeeksAero #AvgeekSchoolofKnowledge #AvGeekNation #TeamAvGeek #MD80Sunset (at Dallas/Fort Worth Intl Airport (DFW)) https://www.instagram.com/p/B2Axk-qBjLX/?igshid=n5gf5vebt5vn

[sentinelchicken]

Big thank you to the @dfwairport social media team for the hospitality this morning to give the American Airlines MD-80s an avgeekworthy (yes, I just made up that word but it’s an awesome word) send off into retirement. This is my ugly mug in front of N984TW before it’s pushed back as AA80 to ORD as the last American revenue MD-80 revenue service. #Avgeek #aviation #aircraft #planeporn #KDFW #DFW #dfwavgeek #airport #planespotting #airlines #McDonnellDougas #MD80 #American #AmericanAirlines #N984TW #instagramaviation #splendid_transport #instaaviation #aviationlovers #aviationphotography #flight #AvGeeksAero #AvgeekSchoolofKnowledge #AvGeekNation #TeamAvGeek #MD80Sunset (at Gate C2 - Dallas/Fort Worth International Airport) https://www.instagram.com/p/B2AH3vtBI1V/?igshid=15msiflek1nra