Aircraft Accident/Incident Report

Westerly, Rhode Island 02891
Saturday, July 13, 1996 20:40 EDT

NTSB Narrative Summary Released at Completion of Accident

The first officer (F/O) was making a descent from FL350 to FL240 in smooth air in VMC conditions with the autopilot (A/P) engaged. As the flight (flt) neared FL250, the captain became concerned that the airplane would not level off at FL240. He instructed the F/O to slow the rate of descent. The F/O attempted this by using the pitch thumbwheel on the A/P control panel. The captain then took control, attempted to overpower the A/P, and pulled back on the control yoke. With back pressure on the control yoke, he disengaged the A/P. With the reduced control column resistance after the A/P was disengaged, there was further excursion of the elevators to the up position. According to the flt data recorder, the airplane was subjected to a +2.28 G-load. A passenger in the aft lavatory suffered a fractured ankle. A 2nd passenger and 2 flt attendants received minor injuries. The MD-11 Flight Crew Operating Manual (FCOM) advised against attempting to overpower the A/P; however, this was contained under the title, 'SEVERE TURBULENCE AND/OR HEAVY RAIN INGESTION.' Each use of pitch thumbwheel interrupted the automatic level off, and the system would wait for 2 seconds after release of the thumbwheel before initiating a level off sequence again. Continued use of the thumbwheel precluded the A/P from performing the level off at FL240. The manufacturer has issued FCOM changes to warn pilots about the hazards of applying force to the control wheel or column while the A/P is engaged and adjusting the pitch thumbwheel during a level off.

NTSB Probable Cause Narrative

insufficient information from the manufacturer in the airplane flight manual and flightcrew operating manual regarding the hazards of applying force to the control wheel or column while the autopilot is engaged and adjusting the pitch thumbwheel during a level off. Also causal was the flightcrew's lack of understanding of these items and the captain's improper decisions to overpower the engaged autopilot and then to disconnect the autopilot while holding back-pressure on the control yoke.

Event Information

Type of Event Accident
Event Date 7/13/1996
Event Day of the Week Saturday
Time of Event 2040
Event Time Zone Eastern Daylight Time
Event City WESTERLY
Event State RHODE ISLAND
Event Country --
Zipcode of the event site 02891
Event Date Year 1996
Event Date Month 7
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude
Event Location Longitude
Event Location Airport
Event Location Nearest Airport ID
Indicates whether the acc/inc occurred off or on an airport Off Airport/Airstrip
Distance from airport in statute miles --
Degrees magnetic from airport --
Airport Elevation --
Weather Briefing Completeness Full
Investigator's weather source Weather Observation Facility
Time of the weather observation 2100 Eastern Daylight Time
Direction of event from weather observation facility (degrees) 80
Weather Observation Facility ID JFK
Elevation of weather observation facility 13
Distance of event from weather observation facility (units?) 100
Time Zone of the weather observation EDT
Lighting Conditions Day
Lowest Ceiling Height 0
Lowest Non-Ceiling Height 2800
Sky/Lowest/Cloud Conditions Scattered
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 10
Air Temperature at event time (in degrees celsius) 23
Dew Point at event time (in degress fahrenheit) 18
Wind Direction (degrees magnetic) 270
Variable Wind Indicator Unknown
Wind Speed (knots) 14
Wind Velocity Indicator Unknown
Wind Gust Indicator Unknown
Wind Gust (knots) 20
Altimeter Setting at event time (in. Hg) 29
Density Altitude (feet) --
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury Serious
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor 3
Injury Total None 176
Injury Total Serious 1
Injury Total All 4
Investigating Agency NTSB
NTSB Docket Number (internal use) 1447
NTSB Notification Source --
NTSB Notification Date Jul 14 1996 12:00AM
NTSB Notification Time 1340
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 8 2000 10:13AM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N1768D
NTSB Number NYC96LA148
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 121: Air Carrier
Type of Flight Plan filed IFR
Flight plan Was Activated? --
Damage None
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name McDonnell Douglas
Aircraft Model MD-11
Aircraft Series Identifier MD-11
Aircraft Serial Number 48436
Certified Max Gross Weight 618000
Aircraft Category Airplane
Aircraft Registration Class U.S. Registered/U.S. Soil
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 283
Number of Engines 3
Fixed gear or retractable gear Retractable
Aircraft, Type of Last Inspection Continuous Airworthiness
Date of Last Inspection --
Airframe hours since last inspection --
Airframe Hours --
ELT Installed No
ELT Activated Unknown
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name AMERICAN AIRLINES, INC.
Aircraft Owner Street Address P.O. BOX 619616
Aircraft Owner City DALLAS
Aircraft Owner State TX
Aircraft Owner Country
Aircraft Owner Zipcode 75261
Operator is an individual? --
Operator Name AMERICAN AIRLINES
Operator Same as Owner? No
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address
Operator City
Operator State
Operator Country
Operator Zip code
Operator Code AALA
Owner has at least one certificate Yes - certificate holder
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation Unknown
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not Scheduled
Indicates Domestic or International Flight International
Operator carrying Pax/Cargo/Mail Passenger/Cargo
Type of Flying (Per_Bus / Primary) Unknown
Second Pilot on Board Yes
Departure Point Same as Event No
Departure Airport Code EGLL
Departure City LONDON, UK
Departure State OF
Departure Country
Departure Time 1333
Departure Time Zone EDT
Destination Same as Local Flt --
Destination Airport Code KJFK
Destination City JAMAICA
Destination State NY
Destination Country
Specific Phase of Flight Descent
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jan 2 2001 10:30AM
User who most recently changed record dbo
Since inspection or accident --
Event Location Runway Number and Location 0
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --