Posted on 11/27/2002 9:42:19 AM PST by Asmodeus
WASHINGTON (AP) - The Federal Aviation Administration is requiring about 3,500 Boeing jets to fly with extra fuel to prevent fuel pumps from overheating and possibly causing an explosion.
The FAA has sent airlines three safety warnings about the problem since August. The latest was issued last weekend after pumps in three planes overheated, the FAA said Tuesday.
The warning is intended as a precaution while the FAA figures out what's causing the problem with the pumps, made by Hydro-Aire Inc. of Burbank, Calif.
James McKenna, managing editor of Aviation Maintenance magazine, said the FAA doesn't ordinarily need to make a third attempt to ascertain what's wrong.
"That tends to unsettle the FAA," McKenna said.
No serious problems have been linked to the problem. However, if a pump overheats, the right mixture of temperature, oxygen and fuel can cause an explosion, McKenna said.
FAA spokesman Paul Takemoto said the extra fuel eliminates the possibility of an explosion.
"There's no danger of (the pumps) igniting fuel vapors if they're covered," he said.
The warning will remain in effect until the agency determines what causes the fuel pumps to overheat, Takemoto said.
The order affects about 1,400 planes — 737s, 747s and 757s flown by U.S. carriers. The FAA is also sending the advisories to its counterpart agencies overseas, covering another 2,100 jets.
The National Transportation Safety Board ruled that an explosion in the fuel tank of TWA Flight 800, a Boeing 747, caused it to crash off the coast of Long Island in 1996, killing 230 people. Vapors in the partly empty tank probably were ignited by a spark in the wiring, the NTSB said.
In August, the FAA ordered airlines to submerge certain Hydro-Aire pumps with fuel or, if not, to X-ray them to make sure they were properly wired. If they weren't, they had to be replaced.
Major U.S. carriers said they had few planes in which the suspect pumps were installed.
In September, the FAA found the problem potentially included every Hydro-Aire pump and ordered all fuel pumps submerged or X-rayed and replaced if faulty.
Then, last week, Boeing Co. received reports of overheating in fuel pumps that had been replaced on a Singapore Airlines 747 and on a Lufthansa 747.
The overheating of those pumps wasn't caused by faulty wiring, said Boeing spokeswoman Cindy Wall.
A pump on a third plane had been removed and was found to have overheated during an inspection.
"It's baffling," Wall said. "They've been working nonstop 24 hours a day trying to fix it."
Hydro-Aire President Greg Ward said the company has made the pumps for 30 years without a problem. It's conducting an extensive investigation that includes chemical analysis of pump parts that overheated, checking airline service records and interviewing retired employees who worked on the pumps, he said.
"We're still piecing together clues," Ward said.
Perhaps. But most likely misinformed by the purveyors of the impossible.
8:31:11 Intact and climbing 747 approaches 13,800 feet.
8:31:12 Initiating Event at 13,800 feet followed immediately by the commencement of the decapitation process.
8:31:43-8:31:47 Streak of light appears.
8:31:47 Explosion of Massive Fireball at 5500-7500 feet.
8:31:55-8:31:57 Splashdown of the Massive Fireball flames.
Source.
Memorandum
To: Thomas H. Jourdan
From: William A. Tobin
Date: 07-15-97
Subject: Metallurgical Status Report: TWA 800
The last FBI metallurgical examinations or evaluations conducted of any significance, relating to damaged TWA 800 components, were in approximately October 1996.
As directed by you, on January 1, 1997, I elicited a commitment for the services of a retired research scientist and metallographic laboratory specializing in the aluminum alloys primarily comprising the Boeing 747-100.
Since May 1997, the scientist has been researching the location, morphology, and formation fracture mechanics of small holes with "spike tooth" fractures, the only metallurgically significant indicator present at a high strain rate. However, the holes are relatively small (none of which could reasonably have been responsible for "instantaneous" cessation of the recorders), exhibit no apparent preferred concentration, exhibit no apparent isotrophy, and are in matrices which exhibit no characteristics of impulsive loading or proximity to explosive (ordnance) materials.
The scientist has observed no indication of bomb or missile damage, and brings to ten the number of metallurgists officially examining and pronouncing the absence of bomb or missile damage, four from NTSB, three from Boeing, two from FBI Laboratory, and one scientist consultant.
It is noted that three of the aforementioned metallurgists could be considered to have a strong organizational interest in the finding that something other than mechanical failure initiated the catastrophic sequence of events.
Source.
ABOUT THAT TWA-800 ANIMATION
We at Heads Up know next to nothing about commercial aircraft, or the actual cause of (many) aircraft crashes. But, like many others, I had my own favored scenario (of the many available) on the TWA Flight 800 demise.
This, however, is not a conspiracy oriented publication. So, due to the lack of anything resembling evidence, I kept my personal opinion out of here. I did, however, ask many questions of people involved in the aircraft industry. And one very experienced expert agreed to put his thoughts on the crash into words for Heads Up readers.
First, if I may, let's introduce our expert:
David Buck is a retired U.S. Air Force Major with over 4000 hours in the B-52. A good part of his Air Force experience included using the B-52 for that which it was intended: war. He was also an instructor pilot in the B-52, and is currently a commercial airline captain with over 10,000 hours of total flying time.
David Buck has a B.S. in mathematics and physics from Augusta College in Augusta, Georgia. He also holds an M.S. in Aeronautical Science (MAS) and an MBA in Aviation from Embry-Riddle Aeronautical University in Daytona Beach, Florida. While matriculating for his MAS, he received a grade of "A" in Boeing 747 systems.
Since 1984, David Buck has been an Adjunct Professor at Embry-Riddle Aeronautical University Campus of Continuing Education. He teaches Aerodynamics, Aircraft Stability and Control, Boeing 757 and 767 systems, Aircraft Safety and Accident Investigation, and 16 other aviation related courses at the master's level.
David watched the animated presentation offered by the FBI and read many of the speculations I found floating around on the Internet. Having spent all of his adult life flying, and teaching about aircraft and flying, he is uniquely qualified to comment on this issue.
I might also add that I have known David for a number of years. Therefore, I can personally certify that he has no relationship to any government organization -- other than the hoops the FAA makes commercial airline pilots jump through to keep their licenses, that is. The opinion below is, therefore, strictly his own opinion, independently derived, and based on many years of professional experience.
There are two parts to this report: A discussion (at times rather technical) of the ability of the aircraft to "climb" after the explosion, and the potential cause of the actual explosion.
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There seems to be quite a lot of speculation concerning the events surrounding the TWA Flight 800 crash. I, of course, was not near the crash site at any time. But, perhaps I can shine a little light on some aspects of the subject from my point of view.
First, let's examine the possibility of the 747 gaining altitude after the initial explosion which blew the nose off the aircraft.
Most airliners climb at 250-280 knots indicated air speed below 10,000 ft. Unless more speed is required for the safety of the flight, the FAA restricts aircraft to a maximum speed of 250 knots below 10,000 ft. At 10,000 ft., they accelerate to 320 knots indicated air speed. (1 knot = 1.15 mph) Therefore, 320 knots indicated air speed x 1.15 = 368 mph.
Airspeed has nothing to do with stall. According to Dr. Charles E. Dole -- B.S. in mechanical Engineering Drexel institute of technology, B.S. in Aeronautical Engineering US Navy Post graduate School, M.S. in Aeronautical Engineering University of Minnesota, Ed.D. University of Southern California -- in his book "Flight Theory and Aerodynamics" pages 44 and 45, "Stall is the condition of airflow separation of the boundary layer from a lifting surface. It is characterized by a loss of lift and an increase in drag." Stall occurs at a single angle of attack, which depends on aircraft weight, air density, and maximum coefficient of lift. For these conditions, stall occurs at a particular airspeed. Dole's book is one of the books I have used to teach aerodynamics at the master's level.
Dole goes on to say that stall has to do with the angle of attack of the wing, not the speed of that aircraft. Because of weight, aircraft configuration -- i.e. gear up, gear down, flaps extended, etc. -- and altitude, the aircraft will stall at a specific angle of attack. For a commercial aircraft we don't even get what is called the shaker (a device which shakes the control column, the first warning of stall) until 15 degrees nose high or more. To get out of a severe wind sheer or microburst effect, we are taught to go to 15 degrees nose high, find the shaker, then lower the nose just out of shaker. And let me tell you, that is an uncomfortable high angle of attack. In the simulator, I have to really force myself to hold the aircraft in that high of an angle of attack.
Normally, the aerodynamic center of lift, or aerodynamic center, does not move with changes of the angle of attack. The aerodynamic center varies slightly, depending on airfoil shape. Subsonically, it is located between 23 and 27% of cord. (Chordline is a straight line connecting the leading edge of the wing and the trailing edge of the wing. Cord is the length of the cordline.)
For maximum stability, it is preferable that the center of gravity be ahead of the aerodynamic center of the aircraft. This is desirable in larger aircraft like airliners, bombers, and transport aircraft. But this does not necessarily have to be the case, and in fact is not, with many fighter aircraft or with the B-1 and the B-2 bombers.
During U.S. Air Force pilot training and after, we pilots were taught that if we were low to the ground and in trouble, we were to do what is called a "zoom" maneuver. The idea of this maneuver is to pull back on the stick or yoke and trim nose up to get the aircraft going up and the aircraft momentum moving in an upward direction. This maneuver, of course, trades airspeed for altitude, but keeps the momentum going up so the pilot can eject. As expected, this maneuver produces very high rates of climb. I have seen video of an F-4, starting a few feet above the ground, go straight up and the pilots eject safely. The maneuver saved many a life and also makes for good video to sell on TV.
If the nose was blown off of TWA Flight 800, the center of gravity would shift aft, toward or behind the aerodynamic center. The aircraft would then pitch up, in a zoom maneuver. The aircraft may be in an accelerated stall, but it will still go up very rapidly.
That is because, at that point in time in the aircraft's assent, the engines were at near full thrust. And, due to a series of built in safety devices on all hydraulic control circuits, known as hydraulic "fuses," all controls should have remained at their settings. All that changed, then, was the center of gravity, which would accentuate climb. And, yes, the aircraft will fly without the nose section. In fact, given enough thrust or velocity, we can even make a barn door fly.
I'm not sure, but 240 people on a 747 may not be a full load. I will try to find out how many people that type of 747 can carry. It seems to me that, depending on it's configuration (to carry cargo, etc.), the aircraft should be able to carry 380 to 420 people. Therefore, with only 240 passengers, the aircraft would have been light.
So, as we see, the aircraft was not in cruse flight at the time of the explosion, but in a climb. Hence, the engines would have been at near full thrust, and after the initial explosion, the aircraft could have had a very high rate of climb.
However, this is only speculation on my part. The only way to prove what happened is to use a 747 simulator -- or the aircraft similarly loaded and then remove the nose at the some point. Good luck.
With all that said, let's examine the fuel tank explosion:
In 1988 or 1989, a U.S. Air Force KC-135 (Boeing 707) exploded while in the traffic pattern on returning to Loring AFB, Maine after a night refueling training mission. The cause of the explosion was determined to be the copilot turning off the air refueling boost pumps in an empty fuel tank. As the Air Force investigation determined, the spark arresters on one of the boost pumps were improperly installed. The tail of the KC-135 was blown off, resulting in the destruction of the aircraft and the death of all on board.
The U. S. Air Force fuels its aircraft with a fuel called JP-4. Commercial airliners are fueled with a fuel called Jet-A. Basically, the fuels are both the same. They are a grade of kerosene (wide cut gasoline). This is a safer fuel than straight high-octane gasoline. A lighted match can be plunged into JP-4 or Jet-A without igniting either fuel.
The problem occurs when the fuel tank is empty, when the fuel boost pump is not covered with fuel, and (if) the spark arresters are improperly installed. The liquid fuel is not explosive, but an air-fuel vapor mixture is highly explosive. One small spark from a boost pump with no, or improperly installed, spark arresters and you have an explosion.
In the late 1970's or early 1980's, at Kelly AFB in San Antonio, Texas, a B-52 aircraft exploded on the ground when two mechanics were testing fuel boost pumps they had just installed in an empty fuel tank. This resulted in adding a warning to the B-52 flight manual.
Incidentally, a "warning" in a U.S. Air Force flight manual means -- and I quote from the T.O. 1B-52G-1 -- "Operating procedure, technique, etc, which will result in personal injury or loss of life if not carefully followed." The warning says: "Do not operate or turn on or off fuel boost pumps in empty fuel tanks. This may result in a fire or an explosion."
Although B-52 and KC-135 aircraft are normally assigned to the same base, this warning did not appear in the KC-135 flight manual before the mishap at Loring AFB.
That empty tank on TWA Flight 800 would have had a fuel boost pump in it. The Flight Engineer could have inadvertently turned that boost pump on, mistaking it for another pump he wanted to place in the "on" position. The fuel boost pump switches are grouped together on the fuel control panel.
The Flight Engineer who was a passenger on board the aircraft was the roommate of a friend of mine. My friend, who was not on that aircraft, and his roommate, who was riding on the flight, had just been qualified in the 747 as flight engineers. Hearsay has it that the Flight Engineer who was operating the flight had also just recently qualified as a 747 flight engineer.
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So, there you have it, folks. If this is not the complete story, then at least it is a plausible scenario. Unfortunately, there's still an "if" in there: As in "if" the spark arresters were missing, or "if" they were improperly installed. Maybe the NTSB investigation will tell us someday, but I wouldn't bet on it. In fairness, they may never even find all the parts.
Questions remaining: Why does the Air Force have a "warning" concerning operating fuel pumps in an empty tank, but not the FAA? And, how do we explain the eye witness reports of the TWA Flight 800 crash?
[We must add that the above text was edited for clarity. So, if there is some sort of slight technical error, it probably happened on this end.]
Your comments continue to dramatize why every member of congress, past and present, and every member of the mainstream press have turned their backs on the TWA 800 "shootdown" or "bomb" conspiracy theorists.
Here's a spoof on the "shootdown" guys vs. the "bomb" guys dispute.
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