# NTSB CHI76IC032: Boeing 747, N4711U, Boston, MA, October 21, 1975

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Closed
- Date: October 21, 1975
- Place: Boston, MA · BOSTON, MA
- Location: 42.3584° N, 71.0598° W: Placed by OpenAirDocs: center of Boston, MA, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=42.3584&lon=-71.0598&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 128 uninjured
- Status: Completed, report January 16, 1976
- Report: Brief approved by the director
- NTSB case key (mKey): 151326
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI76IC032
- Page: https://openairdocs.org/ntsb/CHI76IC032

## NTSB brief

```
----------------------------------------------------------------------------------------------------------------------------
 FILE    DATE          LOCATION          AIRCRAFT DATA       INJURIES       FLIGHT                        PILOT DATA
                                                               F  S M/N     PURPOSE
----------------------------------------------------------------------------------------------------------------------------
4-0028  75/10/21   BOSTON,MA           BOEING 747          CR-  0  0 14  SCHED DOM PASSG SRV       AIRLINE TRANSPORT, AGE
        TIME - 0946                    N4711U              PX-  0  0114                            UNK/NR, UNK/NR TOTAL
                                       DAMAGE-MINOR        OT-  0  0  0                            HOURS, UNK/NR IN TYPE,
                                                                                                   INSTRUMENT RATED.
        CLASSIFIED AS INCIDENT
        NAME OF AIRPORT - LOGAN INTL
        OPERATOR - UNITED AIR LINES,INC.
        DEPARTURE POINT             INTENDED DESTINATION
          BOSTON,MA                   SAN FRANCISCO,CA
        TYPE OF ACCIDENT                                         PHASE OF OPERATION
           AIRFRAME FAILURE: IN FLIGHT                              TAKEOFF: INITIAL CLIMB
        PROBABLE CAUSE(S)
           SYSTEMS - FLIGHT CONTROL SYSTEMS: WING LEADING EDGE FLAP SYSTEM
           MISCELLANEOUS ACTS,CONDITIONS - OVERLOAD FAILURE
           MISCELLANEOUS ACTS,CONDITIONS - SHEARED
        EMERGENCY CIRCUMSTANCES - PRECAUTIONARY LANDING ON AIRPORT
                                  SUSPECTED OR KNOWN AIRCRAFT DAMAGE
        REMARKS- ELECT-PNEU DRIVE UNIT SHEAR PINS(P/N 885004-1,112479-39),LMT SWTCHES (P/N 886039-6,886149-2) FAILD
```

## Aircraft

- Registration: N4711U (not matched to a registry record)
- Reported make and model: BOEING 747
- Category: Airplane
- Engines: turbo fan
- Damage: Minor damage
- Airport: Logan Intl

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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