ASN Wikibase Occurrence # 374792
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| Date: | Tuesday 24 June 1986 |
| Time: | 12:00 LT |
| Type: |  Boeing 747-122 |
| Owner/operator: | United Airlines |
| Registration: | N4718U |
| MSN: | 19879/139 |
| Year of manufacture: | 1971 |
| Fatalities: | Fatalities: 0 / Occupants: 436 |
| Aircraft damage: | None |
| Category: | Serious incident |
| Location: | Pacific Ocean -
 Pacific Ocean
|
| Phase: | En route |
| Nature: | Passenger - Scheduled |
| Departure airport: | Chicago, IL (KORD) |
| Honolulu-Daniel K. Inouye International Airport, HI (HNL/PHNL) | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
WHILE UAL FLT 1 WAS CRUISING AT FL 310, APRX 1.8 HR AFTER TAKEOFF, A FLT ATTENDANT (F/A) RPRTD A HEADACHE & LIGHTHEADED-NESS. THE FLT CLIMBED TO FL 350, THEN ANOTHER F/A & SVRL PAX RPRTD SIMILAR SYMPTOMS. AT THAT TIME, THE TROPOPAUSE WAS AT40,000'. AS THE FLT CONTD, THE TROPOPAUSE LOWERED SOME, THEN INCREASED IN ALT. SUBSEQUENTLY, SVRL OTHER OCCUPANTS HAD SIMILAR SYMPTOMS. THE CAPT TURNED ON THE 'NO SMOKING' SIGN AS A PSBL SOLUTION, BUT THIS DID NOT SEEM TO HELP. NO HAZARD-OUS CARGO LEAK WAS FND & NO PAX ADMITTED CARRYING BUTANE OR OTHER SUCH SUBSTANCE. THOSE AFFECTED BY THE PSBL IRRITATING OR GASEOUS SUBSTANCE WERE IN ZONES B, C, D, E OR THE UPPER DECK OF THE ACFT. NO OCCUPANTS OF ZONE A OR THE FLT DECK WEREAFFECTED, EXCEPT THE 2ND OFFICER RPRTD A SLIGHT PAIN BETWEEN HIS EYEBROWS AFTER SPENDING 10 TO 20 MIN IN THE PAX CABIN. AN INVESTIGATION FOR A POSSIBLE OZONE ENCOUNTER WAS MADE, BUT NO SPECIFIC EVIDENCE WAS FOUND. THE CATALYTIC CONVERTERS IN THE AIR CONDITIONING SYS WERE TESTED & FOUND TO BE 51.2% EFFICIENT.
Probable Cause:
Accident investigation:
 |
|
Sources:
NTSB LAX86MA275
History of this aircraft
Other occurrences involving this aircraft
| 11 February 1987 | N4718U | United Airlines | 0 | Detroit, MI |  |
non |
| 12 February 1987 | N4718U | United Airlines | 0 | Detroit, MI | |
non |
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 28-Mar-2024 13:02 | ASN Update Bot | Added |
Corrections or additions? ... Edit this accident description
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