Engines thrust power reduction, page 4
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reply posted on 9-4-2006 @ 11:51 AM by bigx01
Originally posted by elpasys
On January 13, 1982, Air Florida Flight 90, a Boeing 737-222 (N62AF) was a scheduled flight to Fort Lauderdale, Florida, from Washington National Airport, Washington, D.C. The scheduled departure time was delayed about 1 hour 45 minutes. The aircraft took off in heavy snow. The tower lost sight of Palm 90 during it's roll due to the reduced visibility, but radar showed it airborne and the tower controller instructed Palm 90 to contact the departure controller. Less than a minute after taking off, Palm 90 descended at low airspeed into the Rochambeau bridge and plowed through into the Potomac river, 0.75 nmi from the departure end of runway 36.

Beginning information gave evidence of airframe icing, but further analysis showed other probelms with Palm 90. Shortly before takeoff, the crew have a brief discussion concerning anomalies in the engines. The indications seemed to return to near normal as Palm 90 got closer to takeoff. As Palm 90 was cleared for takeoff, the pilot remarked at the abnormal indications from the engines again. During takeoff the the aircraft was not accelerating properly due to fuel's entropy. The aircraft traveled almost 1/2 mile (800 m) further down the runway than is customary before liftoff was accomplished. Still, 45 seconds into the takoff roll, Palm 90 reached it's rotation speed and pitched up abruptly. Survivors indicated the trip over the runway was extremely rough, one of whom admitted he feared that they would not get airborne and would "fall off the end of the runway."

Although the aircraft did manage to become airborne, it failed to gain altitude, then the stall warning came on, "Forward! Forward!", indicating to lower the nose to prevent the stall. and. The aircraft remained airborne for only 30 seconds. The pilot believed that the engines were producing max thrust during takeoff.

The CVR recording ended with the crew's final acknowledgement of the severity of their situation. "Larry-we're going down Larry!". "I know it!".

There were 74 passengers, including 3 infants, and 5 crew members on board. Only six people survived.

The National Transportation Safety Board determines that the probable cause of this accident was the flight crew's failure to use engine anti-ice during ground operation and takeoff, their decision to take off with snow/ice on the airfoil surfaces of the aircraft, and the captain's failure to reject the takeoff during the early stage when his attention was called to anomalous engine instrument readings(!).


now this is not because of the fuel. the power probe on one engine was iced over giving false readings. hence the confusion over the ammount of thrust the engine was giving.

the biggest factor in this crash was the inexperience of the crew due to the recent mergers.

read the book "blind trust" from john nance. he goes indepth on this crash and how deregulation caused a spate of crashes early on into the new era of deregulation


reply posted on 9-4-2006 @ 12:23 PM by bigx01
Originally posted by elpasys
Entropy = Cavitation

"Cavitation occurs in pumps, as well as around propellers, or at restrictions in a flowing liquid. Cavitation means that cavities are forming in the liquid being pumped. Cavitation also reduces efficiency dramatically."

See: Cavitation
in Nedeworks Encyclopedia,
pedia.nodeworks.com...


the only way you are going to have cavitation is if it is pumping the wrong liquid.

a little refinery lesson for you elpasys.

pumps are not just made and you throw them in. a pump that is going to pump a liquid as heavy as jet fuel will not pump will not pump something as light as naptha. also a pump that will pump a light liquid like propane will not pump jet fuel.

so if you are getting cavitation on a pump that is pumping jet fuel then you really aren't pumping jet fuel

positive dispalcement pumps don't cavitate, though they can pump liquids of different viscosity though.

[edit on 9-4-2006 by bigx01]
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