Investigation Summary
The flight was intended to qualify Braniff International Airways pilots on the 707 prior to delivery. During the training session, the Boeing instructor pilot initiated a Dutch roll maneuver with a bank angle between 40 and 60 degrees, significantly exceeding the company-prescribed limit of 25 degrees. The trainee pilot, who was unfamiliar with the aircraft's handling characteristics, applied full right aileron while the aircraft was already banking to the right. This improper input caused the aircraft to yaw violently and roll past 90 degrees. The instructor attempted to counter with full opposite aileron, leading to several violent gyrations. The resulting structural loads caused the No. 1, No. 2, and No. 4 engines to tear away from their mounts. Although the crew regained temporary control and attempted an emergency landing in a field, the fire on the left wing destroyed control surfaces and reduced lift. The aircraft struck trees and crashed approximately half a mile short of the intended landing site. The forward section was destroyed by impact and fire, while the tail section broke off and landed in the river. The four survivors, who were seated in the aft section, were all aviation professionals acting as observers: a Braniff flight engineer, a Braniff technical instructor, a Boeing pilot, and an FAA inspector.
Final Conclusions
The Civil Aeronautics Board (CAB) determined the probable cause was structural failure induced by an improper recovery attempt from a Dutch roll that exceeded prescribed bank-angle limits. The board noted there was no instructional value in performing the maneuver at such extreme angles. The accident led to significant design changes for the Boeing 707, including an increase in the vertical stabilizer area and the implementation of a full-time boosted rudder to improve directional stability.
Video Analysis
No video analysis linked for this case file yet.
Airframe & Maintenance
Crew Experience
Captain (Instructor)
Boeing test pilot Russell Baum. Instructor pilot.
Captain (Trainee)
Braniff pilot John Berke. Trainee pilot in left seat.
Captain (Trainee)
Braniff pilot Frank Staley Jr.
Flight Engineer
Boeing employee Carl Hagan.
Systems & Failure Modes
Vertical Stabilizer
Following the crash, Boeing increased the height and area of the 707's tail fin to improve stability during yawing motions.
Rudder Boost
The rudder system was modified to be fully boosted at all times to provide pilots with better control during asymmetric thrust or lateral oscillations.
Engine Mounts
The mounts failed under the extreme side-loads generated by the violent Dutch roll and subsequent recovery attempts.
Interesting Facts
- 01The aircraft had accumulated only 173 total flight hours since manufacture.
- 02Three of the four engines detached from the aircraft in flight due to structural failure of the mounts.
- 03The four survivors were all located in the aft section of the cabin, which detached upon impact.
- 04The accident was the first crash of a Boeing jetliner in its home state of Washington.
Safety Actions & Advisories
707 Tail Redesign
Boeing increased the area of the vertical stabilizer on all 707 models to enhance directional stability and prevent excessive Dutch roll tendencies.
Rudder System Enhancement
The rudder was updated to be hydraulically boosted across its full range of travel to assist pilots in maintaining control during extreme maneuvers.
Location
ACCIDENT SITE · Coordinates taken from the wikidata coordinate.