More Toilets

Date:         18 Mar 97 03:14:51 
From:         gfmoff1@airmail.net (Gary Moffitt)
Organization: INTERNET AMERICA
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I have been amazed at how long the thread of toilets sucking people in has
lasted. Not being one to break a tradition, I have the following to
contribute. What follows is a telex sent from Boeing to various airline
customers. I assure you it is genuine, and, as it is probably proprietary
information I have edited the headers off so the source and destination
won't be know. So here it is straight from Boeing.......

THE FOLLOWING MESSAGE SENT TO ALL BOEING FIELD SERVICE BASES FOR
TRANSMITTAL TO AIRLINE PERSONNEL.  COPIES ARE PROVIDED TO THE AIR
TRANSPORT ASSOCIATION, INTERNATIONAL AIR TRANSPORT ASSOCIATION, AND
RESIDENT AIRLINE REPRESENTATIVES IN RENTON AND EVERETT.

SUMMARY
A RECENT EVENT OCCURRED ON A NON-BOEING AIRPLANE WHERE A PASSENGER WAS
DRAWN INTO A LAVATORY TOILET BOWL AND WAS INJURED.  THIS EVENT HAS BEEN
REPORTED IN THE WORLD PRESS AND ON A TELEVISION NETWORK IN EUROPE.  THIS
MESSAGE PROVIDES INFORMATION ON THE REPORTED EVENT AND ON THE SAFETY
FEATURES OF TOILETS ON BOEING AIRPLANES.


RECENTLY, THERE WAS AN IN-SERVICE EVENT ON A NON-BOEING AIRPLANE
WHICH A PASSENGER, A YOUNG GIRL, WAS INJURED WHILE USING AN
ON-BOARD TOILET.  ACCORDING TO PRESS REPORTS, THE PASSENGER SAT
DIRECTLY ON THE TOILET SHROUD WITH THE TOILET SEAT IN THE UP
POSITION.  THE OVER-BOARD VENTILATION OF THE TOILET WASTE HOLDING
SYSTEM RESULTED IN A VACUUM BEING APPLIED TO THE PASSENGER,
CAUSING THE PASSENGER TO BECOME STUCK ON THE TOILET.  THE
AIRCRAFT DESCENDED TO REDUCE THE PRESSURE DIFFERENTIAL BEFORE THE
PASSENGER COULD BE REMOVED FROM THE TOILET.  WHILE THE EXACT
NATURE OF THE INJURIES ARE NOT FULLY KNOWN TO BOEING, THE
PASSENGER WAS HOSPITALIZED FOR TREATMENT.

AS A RESULT OF THE REPORTING ON THIS EVENT IN THE WORLD PRESS AND ON
EUROPEAN TELEVISION, THE SAFETY OF THE TOILETS ON BOEING AIRPLANES HAS
BEEN QUESTIONED BY SOME OF OUR CUSTOMERS.

BOEING IS NOT FAMILIAR WITH THE DETAILED DESIGN OF THE WASTE SYSTEM ON THE
AIRPLANE INVOLVED IN THIS RECENT EVENT, AND THUS CANNOT FULLY EXPLAIN HOW
IT OCCURRED.  BOEING CAN, HOWEVER, PROVIDE ASSURANCE THAT THE WASTE
SYSTEMS UTILIZED ON BOEING AIRPLANES INCORPORATE DESIGN FEATURES WHICH
PROTECT AGAINST THE OCCURRENCE OF THIS TYPE OF EVENT.

TWO TYPES OF WASTE SYSTEMS ARE UTILIZED ON BOEING AIRPLANES.
SELF-CONTAINED RECIRCULATING SYSTEMS ARE USED ON 707, 727, 737, CLASSIC
747 AND 757 AIRPLANES.  NEW GENERATION 737, 747-400, 767 AND 777 AIRPLANES
INCORPORATE VACUUM WASTE SYSTEMS WHICH UTILIZE TUBES TO TRANSPORT WASTE TO
CENTRAL STORAGE TANKS LOCATED BELOW THE PASSENGER CABIN FLOOR.  THE VACUUM
WASTE SYSTEM WILL ALSO BE USED ON 757-300 AIRPLANES.

THE DESIGN OF THE POST-1970 RECIRCULATING WASTE SYSTEMS PROVIDES REDUNDANT
AIR PATHS (VACUUM BREAKS) TO PREVENT A COMPLETE SEAL FROM BEING FORMED
BETWEEN THE PERSON USING THE TOILET AND THE TOILET SHROUD OR TOILET BOWL.
THE FIRST AIR PATH IS BETWEEN THE TOILET SEAT AND THE TOILET SHROUD.  IF
THE SEAT IS DOWN DURING USE, A COMPLETE SEAL IS NOT POSSIBLE.  THE SECOND
AIR PATH IS BETWEEN THE SHROUD AND THE TOILET BOWL.  WITH THIS SECONDARY
AIR PATH, A COMPLETE SEAL IS NOT POSSIBLE EVEN IF THE TOILET IS USED WITH
THE TOILET SEAT IN THE UP POSITION.  IF A PERSON WAS ABLE TO SIT DIRECTLY
IN THE TOILET BOWL, THE TOILET BOWL VENT LINE WOULD PROVIDE A THIRD AIR
PATH, AGAIN PREVENTING A COMPLETE SEAL FROM BEING FORMED.

THE DESIGN OF VACUUM WASTE SYSTEMS ALSO PROVIDES REDUNDANT AIR PATHS
BETWEEN THE TOILET SEAT AND THE TOILET SHROUD, AND BETWEEN THE SHROUD AND
THE TOILET BOWL, TO PREVENT A COMPLETE SEAL FROM BEING FORMED BETWEEN THE
PERSON USING THE TOILET AND THE TOILET SHROUD.  EVEN IF A PERSON WAS ABLE
TO SIT DIRECTLY IN THE TOILET BOWL, OVERCOMING THE ABOVE AIR PATHS,
FEATURES OF THE VACUUM WASTE SYSTEMS MAKE THEM LESS LIKELY THAN A
RECIRCULATING WASTE SYSTEM TO HAVE SUCH AN OCCURRENCE.  DURING THE USE OF
THE TOILET, THERE IS NO VACUUM IN THE BOWL UNTIL THE TOILET IS FLUSHED.
ACCESS TO THE FLUSH SWITCH WHILE SEATED ON THE TOILET WOULD BE DIFFICULT.
IF THE PERSON WAS ABLE TO FLUSH THE TOILET, THE FLUSH VALVE IS OPEN FOR
ONLY FOUR SECONDS, AT WHICH TIME IT CLOSES AUTOMATICALLY.  LASTLY, IF A
FLUSH VALVE WERE TO REMAIN OPEN, ALL VACUUM TOILETS HAVE A MANUAL SHUT-OFF
VALVE THAT COULD BE CLOSED TO BREAK THE VACUUM PATH.

IT SHOULD BE NOTED THAT TESTS ARE CONDUCTED ON ALL BOEING FIRST OF MODEL
AIRPLANES TO ENSURE THE INTEGRITY OF THE WASTE SYSTEM DESIGN.

WITH THE FEATURES DESCRIBED ABOVE IN PLACE, THIS TYPE OF EVENT COULD NOT
OCCUR ON BOEING AIRPLANES UNLESS A SERIES OF HIGHLY UNLIKELY EVENTS AND
SYSTEM MALFUNCTIONS WERE TO OCCUR.

IF YOU NEED FURTHER INFORMATION REGARDING THIS SUBJECT, PLEASE DIRECT YOUR
REQUEST TO YOUR BOEING CUSTOMER SERVICES REPRESENTATIVE OR AIRLINE SUPPORT
MANAGER...

--
Gary S. Moffitt