Investigation Summary
Flight 389 was a routine scheduled flight from New York to Chicago. The descent from 35,000 feet was initially normal, with the crew acknowledging various altitude clearances. At 2111 CDT, the flight was cleared to 6,000 feet. Radar analysis later indicated the aircraft was already significantly lower than reported when it received this clearance. The final communication occurred at 2120:03. During this exchange, the pilot initially read back the altimeter setting incorrectly, but after being corrected by the controller, he repeated the setting of 29.93 correctly. At this moment, the aircraft was likely within 15 seconds of impact. Witnesses on the shore and on nearby ships reported seeing a ball of fire on the horizon. The aircraft struck the water in a normal descent attitude at approximately 200 knots. The investigation was severely limited by the failure to recover the internal recording media of the Flight Data Recorder (FDR), although the outer casing was found in the mud at the bottom of the lake. The lack of FDR data and cockpit voice recordings (which were not required at the time) left investigators with no evidence of mechanical failure, crew incapacitation, or external factors, leading to an official finding of 'undetermined' cause.
Final Conclusions
The Civil Aeronautics Board (CAB) adopted its final report on December 19, 1967. The Board (the primary federal aviation investigative body prior to the creation of the NTSB in 1967) stated it was unable to determine the reason for the aircraft not being leveled off at its assigned altitude of 6,000 feet. While the report noted that all systems appeared to be operating normally and the crew was not incapacitated, the lack of flight recorder data prevented a definitive conclusion. The NTSB currently serves as the archive for this CAB investigation.
Photographic Evidence (1)
Video Analysis
No video analysis linked for this case file yet.
Airframe & Maintenance
Crew Experience
Captain
Melville W. Towle (born Sept 11, 1922). Certified on DC-3, DC-4, Vickers Viscount, and B727. Last B727 check in July 1965.
First Officer
Roger Marshall Whitezell (born Sept 6, 1930). Qualified on DC-6, DC-7, and small aircraft. Qualified on B727 on Nov 1, 1964.
Second Officer
Maurice L. Femmer (born March 26, 1939). Qualified as flight engineer and single-engine pilot. Certified for B727 on Dec 3, 1964.
Systems & Failure Modes
Three-Pointer (3P) Altimeter
A mechanical instrument using three hands to indicate hundreds, thousands, and tens of thousands of feet. Studies found pilots often misread the 10,000-foot pointer, especially during high-workload descents.
Flight Data Recorder (FDR)
The device casing was recovered from 250 feet of water, but the recording media was missing, depriving investigators of critical flight parameters.
Interesting Facts
- 01The aircraft had been in service for only two and a half months and had completed 138 cycles.
- 02The Flight Data Recorder (FDR) internals and recording tape were never recovered despite two search operations.
- 03The aircraft impacted the water at approximately 200 knots in a normal descent attitude.
- 04Visibility was described by other pilots in the area as fuzzy and unclear with a ceiling of 10,000 feet.
- 05The three-pointer altimeter design used on the aircraft was later found to be eight times more prone to misreading than other designs.
Safety Actions & Advisories
Altimeter Design Review
Source ↗Following studies by the Naval Research Laboratory highlighting the dangers of the three-pointer design, the industry moved toward drum-pointer and digital altimeters to reduce 10,000-foot misread errors.