Twa 800

[Typhoon1244]

This lame brain argument again.

No argument, just wondered what the general concensus was.

What's the matter, Vik? Do you have something to hide, hmm?

(Relax...kidding.)

 

[Jimmy V.]

I remember reading a book by Victor Belenko a couple of years ago. If I am not misstaken he said that the Russians brought this one down. I could be wrong however but for some reason I remember reading about this in his book.


Jimmy

 

[TonyC]

Too many large Boeings with similar fuel systems been flying for 35+ years and only one "blowing up" in flight. Don't buy it.

Good, because it isn't true. As I mentioned, several KC-135's experienced the very same types of explosions with almost identical fuel systems. I lost a friend in such an explosion of a KC-135 at Loring AFB, ME.

Perhaps you should read this story about Boeing's belated concern over fuel pumps in empty tanks:

FAA Issues 3rd Warning on Fuel Pumps


EC/KC/RC-135 operators from that timeframe will remember SAC OPERATING PROCEDURE 90-1 that evolved out of the Loring event:

1. BACKGROUND: POTENTIAL EXISTS FOR HEAT BUILD-UP IN -135 AIR REFUELING/BODY PUMPS WHEN THE PUMPS ARE RUN DRY. THIS HEAT BUILD-UP MAY CAUSE CONDITIONS OF AN EXPLOSIVE NATURE IN THE BODY TANKS. DUE TO THE FUEL QUANTITY SYSTEM TOLERANCES AND DESIGN OF THE LOW PRESSURE WARNING LIGHT SYSTEM, IT MAY BE DIFFICULT TO DETERMINE WHEN A BODY TANK IS EMPTY. NORMAL SYSTEM TOLERANCES CAN RESULT IN A BODY TANK READING OF MORE THAN 500 POUNDS WHEN THE TANK IS IN FACT EMPTY.

2. PENDING ENGINEERING ANALYSIS AND INCORPORATION OF APPROPRIATE DATA INTO THE FLIGHT MANUALS, THE FOLLOWING PROCEDURES AND RESTRICTIONS WILL BE FOLLOWED. THESE PROCEDURES APPLY TO ALL -135 AIRCRAFT FLOWN BY SAC, ANG, OR AFRES AIRCREWS. ... THE PROCEDURES CONTAINED IN THIS OPS PROCEDURE TAKE PRECEDENCE OVER ANY PREVIOUS PROCEDURES.

A. FLIGHT CREWS WILL NOT ACCEPT AN AIRCRAFT FOR FLIGHT WITH LESS THAN 3000 POUNDS OF FUEL IN BOTH THE FORWARD AND AFT BODY TANKS ...

B. AIRCREWS WILL NOT ACCEPT AN AIRCRAFT FOR FLIGHT UNLESS BOTH THE FORWARD AND AFT BODY TANKS HAVE AT LEAST ONE GOOD AIR REFUELING/BODY PUMP. EACH OF THESE TANKS MAY CONTAIN ONE "SUSPECT" PUMP, ANNOTATED AS SUCH IN THE AFTO 781 ("DO NOT OPERATE PUMP OR RESET CIRCUIT BREAKER EXCEPT IN AN EMERGENCY") AND DEACTIVATED BY PULLING AND COLLARING THE 28V DC CIRCUIT BREAKER (CB) WITH A REMOVABLE COLLAR. ... IN AN EMERGENCY, CB COLLARS MAY BE REMOVED AND CIRCUIT BREAKERS RESET TO USE THOSE "SUSPECT" PUMPS. THEIR USE WILL BE LIMITED TO THAT NECESSARY TO SAFELY RECOVER THE AIRCRAFT. AIRCREWS WILL NOT ACCEPT AN AIRCRAFT FOR A PEACETIME FLIGHT WITH A REFUELING/BODY PUMP REMOVED OR AN INOPERATIVE /UNUSABLE PUMP INSTALLED WITHOUT A WRITTEN WAIVER FROM HQ SAC/LGM.

C. THE MINIMUM FUEL LEVEL IN THE FOREWARD AND AFT BODY TANKS IS 3000 POUNDS FOR ALL GROUND AND FLIGHT OPERATIONS. A NON-STANDARD FUEL LOAD WAIVER HAS BEEN GRANTED FOR ALL FUEL LOADS TO MEET THIS REQUIREMENT. THE 3000 POUND FUEL MINIMUM IN BOTH TANKS WILL BE TREATED AS TRAPPED/UNUSABLE FUEL. AS SUCH, IT WILL NOT BE CONSIDERED AVAILABLE FOR DIVERSION OR DELAY. ONLY AN ACTUAL EMERGENCY WARRANTS THE RISK OF DECREASING BODY TANK LEVELS BELOW 3000 POUNDS.

WARNING​

AIR REFUELING/BODY PUMPS SHOULD NOT BE RUN DRY. IF PUMPS OPERATE DRY FOR A PERIOD EXCEEDING TWO MINUTES, DAMAGE TO PUMPS, FIRE AND EXPLOSIONS MAY RESULT.​

D. FOR NORMAL OPERATIONS, AIRCREWS WILL TERMINATE OPERATION OF THE AFT PUMP IN EITHER BODY TANK WHEN THE QUANTITY IN THAT TANK REACHES 5,500 POUNDS. TERMINATE OPERATION OF THE FORWARD PUMP IN EITHER BODY TANK WHEN THE QUANTITY IN THAT TANK REACHES 3000 POUNDS. WHEN THE LIMIT IS REACHED, OPEN THE APPLICABLE 5 AMP 28V DC PUMP CONTROL CB ON THE SBCBP. ...​

E. ... FLIGHT CREWS OPENING PUMP CIRCUIT BREAKERS AS PRESCRIBED BY THE MODIFIED FUEL BURN PROCEDURES WILL MAKE THE FOLLOWING ANNOTATION IN THE AFTO 781A (INFLIGHT DISCREPANCIES): "NOTE: AR/BODY PUMP CIRCUIT BREAKERS OPENED IAW HQ SAC FUEL BURN PROCEDURE." ...

There have been no further mid-air explosions of -135s.


It's too bad the 747 operators didn't get this message.

 

[TonyC]

Being typed on the 747 and very familiar with the systems of the 747, I am sure that it didn't blow up on it's own. Go ahead and throw a match on a pool of jet a. The match will be extingushed. The fuel must be vaporized to attain the flashpoint for ignition.

The tank was empty. (No Jet-A, just a tank full of vapors.) Does that change your mind?

 

[atrdriver]

My understanding, although it may in fact be incorrect, is that the fuel pumps are not actually in the tank.

As far as TWA wanting to scream for further investigation, if you will remember they were just out of a bankruptsy at the time. Within 6 months of this event they announced that they would be purchasing 1 new aircraft every month for 6 years. Kinda funny sequence, considering they were still in pretty bad financial trouble on July 17, 1996. How did they suddenly get all the money for all those new airplanes?

 

[Vik]

I don't think "concensus" and "TWA 800" can be used in the same sentence anymore.

No argument, just wondered what the general concensus was.

What's the matter, Vik? Do you have something to hide, hmm?

(Relax...kidding.)

 

[skeezer]

As far as TWA wanting to scream for further investigation, if you will remember they were just out of a bankruptsy at the time. Within 6 months of this event they announced that they would be purchasing 1 new aircraft every month for 6 years. Kinda funny sequence, considering they were still in pretty bad financial trouble on July 17, 1996. How did they suddenly get all the money for all those new airplanes?

Probably the same way USAirways found financing for 135 RJs just out of bankruptcy...Some moron lent them the money. Stupid people working in the financial industry does not make for a cover-up. It just makes business as usual in the airline world.

Skeezer

 

[TonyC]

Too many large Boeings with similar fuel systems been flying for 35+ years and only one "blowing up" in flight. Don't buy it.

And if you don't wanna take my word for it, try browsing through this FAA Notice regarding Fuel Tank Ignition Prevention Measures.

Including the KC-135 I mentioned from October 1989, this document lists are 13 civilian and 13 military accounts of fuel tank explosions. All but 4 were Boeing products.

1982: Air Canada DC-9 center wing fuel tank exploded on the ground during maintenance - - Dry running of pumps is the suspected cause.

1990: Phillipine Airline B-737 during taxi - - empty center wing tank exploded.

1970: USAF B-52 during maintenance - - explosion of fuel tank, most likely ignition source traced to arcing or overheat of fuel pump shaft or fuel quantity probe.

1971: Spain Air Force B-707 - - #1 main tank exploded during descent through 17,000'. USAF determined chafing of boost pump wires located in conduits as possible ignition source.

1982: KC-135A near Chicago descending through 12,000' - - forward body tank exploded, initial cause listed as VHF antenna.

1987: KC-135A during landing rollout at Altus AFB, OK - - an explosion and fire occurred following copilot transmission on UHF radio. The UHF wire run near the right aft wing root in the fuselage was melted due to an electrical fault. Fuel vapors in the area of the aft body tank were ignited.

1988: B-52H at KI Sawyer AFB, MI during touch-and-go landing - - at 20 ft AGL the empty aft body tank exploded. Pump num [sic] operating in the aft body tank was cause. Evidence of arcing a [sic] overheat was found.

Sept 1989: KC-135A at Loring AFB, ME, parked following flight - - during system shutdown, explosion in the aft fuselage tank occurred. Source of ignition was believed to be a hydraulically driven fuel pump mounted inside the aft body fuel tank.

Oct 1989: KC-135A at Loring AFB, ME, in local traffic pattern - - explosion in the aft body fuel tank caused hull loss. (Oh, and by the way, the loss of lives - added) Aft body f hydraulically driven pump implicated as source of ignition.

1993: KC-135R at Mitchell Field, Milwaukee during ground maintenance - - center wing tank exploded. Center wing fuel tank fuel pump implicated as source of ignition.

 

[Vik]

I think there was an Iran Air 747 that also blew up due the center tank issue.

 

[chperplt]

There was also a Thailand government 747 that blew up at on the ramp shortly after TWA 800 went down.

 

[TonyC]

I think there was an Iran Air 747 that also blew up due the center tank issue.

The above cited report mentions a "special investigation of the May 9, 1976, explosion and in-flight separation of the left wing of an Iranian Air Force Model 747-131, as it approached Madrid, Spain, following a flight from Iran. Witnesses reported seeing a lightning strike to the left wing, followed by fire, explosion, and separation of the wing." The wreckage revealed evidence of an explosion that originated near a fuel valve installation in the left outboard main fuel tank.

 

[CitationLover]

It's unorthadox in an airplane that's neither certified nor stressed for it.

just curious (yes i do not like caps)....

at 90deg bank, what would you do with the ailerons/rudder keeping in mind you have the benefit of hindsight and not .5sec to do something. the poor fo is a scapegoat. all i said was he did a "standard" recovery in terms of basic aerodynamics.

 

[Typhoon1244]

TonyC,

I read the accident summaries and the excerpt from 90-1 you posted with great interest. I'm almost convinced that the official explanation for this incident makes sense, except for one major issue...but I'll come back to that in a second.

One thing I noticed in 90-1 is that the main issue they seem to have been concerned about was heat, not arcing.

POTENTIAL EXISTS FOR HEAT BUILD-UP IN -135 AIR REFUELING/BODY PUMPS WHEN THE PUMPS ARE RUN DRY. THIS HEAT BUILD-UP MAY CAUSE CONDITIONS OF AN EXPLOSIVE NATURE IN THE BODY TANKS.

Does anyone know whether or not the center tank pumps on N93119 were running as it climbed out on July 17th?

In any case, it's my understanding that for a given quantity of Jet-A to ignite, it must be heated and misted. I didn't think "fumes" were enough to cause an explosion, regardless of what the ignition source is. But when you read about all those lost Stratotankers...perhaps I'm mistaken.

Now, back to the major problem I have with the official explanation: if TWA 800 was brought down by an accidental explosion in the center tank, then what exactly did all those witnesses see?

I don't buy the CIA's "zoom climb" story. The aerodynamics and radar data don't support that. And the Agency's story about people being misled by the differing speed of sound and light doesn't apply to those who were looking up at 800 before the explosion.

As I said, eyewitness accounts are notoriously misleading, particularly when it comes to aircraft accident investigation. But are we really supposed to believe that two hundred people--including a handful of military pilots--all got it wrong?

 

[fastandlow]

And if you don't wanna take my word for it, try browsing through this FAA Notice regarding Fuel Tank Ignition Prevention Measures.

Including the KC-135 I mentioned from October 1989, this document lists are 13 civilian and 13 military accounts of fuel tank explosions. All but 4 were Boeing products.

1982: Air Canada DC-9 center wing fuel tank exploded on the ground during maintenance - - Dry running of pumps is the suspected cause........

Lot more instances that I was aware of, but the point remains that there are an awful lot of 747 series AC that have and are still flying and this scenario is just too rare, making me suspect something else. But this is based on intuition and limited experience with this equipment.

Assuming it was a fuel tank explosion, where does the oxygen come from? I'd think, even though it's not very volitile, the jet fuel vapors would displace any oxygen in a partially or even empty fuel tank.

 

[Typhoon1244]

"...In congressional testimony and in statements repeatedly made in the media, the NTSB leadership cited the loss of an Air Force 707 and three KC-135 air to air tanker aircraft, to fuel tank explosions as examples of mishaps similar to TWA Flight 800. Col. Dougherty’s office of the Air Force’s safety center says, “there is no record of a 707 loss and all three KC135’s were fueled with JP4, a fuel as volatile as automobile gasoline”. “Since switching to the military equivalent of...Jet-A fuel the Air Force has not had a problem.”

This is from Commander William Donaldson's report to the Congressional Subcommittee on Aviation two years after TWA 800 went down.