721
1987-APR-13 · Near Kansas City, Missouri

Buffalo Airways — Flight 721

A Boeing 707 cargo flight crashed into a ridge during an ILS approach to Kansas City International Airport after the captain intentionally descended below the decision height. Despite two low-altitude warnings from air traffic control, the crew failed to arrest the descent until seconds before impact. The investigation revealed that the aircraft was significantly below the glideslope and that the Ground Proximity Warning System (GPWS) failed to activate for unknown reasons. All four people on board, consisting of three crew members and one authorized passenger, were killed.

Aircraft
Boeing 707-351C
Registration
N144SP
Phase
Cause
Souls on Board
4
Fatalities
4
Origin → Dest
Wichita-Mid-Continent Airport, KS → Kansas City International Airport, MO
Report

Investigation Summary

Buffalo Airways Flight 721 was a multi-leg cargo operation for Burlington Air Express, originating in Oklahoma City. During the leg from Wichita to Kansas City, the crew faced deteriorating weather including fog and a 100-foot ceiling. Per company regulations, the captain took control from the first officer for the approach due to the low visibility. Although the flight was cleared for the ILS runway 1 approach, the aircraft never properly intercepted the glideslope and continued a steady descent into terrain. The Automated Radar Tracking System (ARTS III) at the control tower triggered a Minimum Safe Altitude Warning (MSAW), prompting the controller to issue two urgent altitude alerts. The crew did not acknowledge these warnings; instead, the captain requested a radio altimeter reading. The first officer reported 1,200 feet on the radio altimeter, a figure that contradicted the aircraft's actual position near a 950-foot ridge, suggesting a misidentification of the instrument or extreme crew confusion during the CRM breakdown. A 'pull it up' command was heard on the cockpit voice recorder only one second before the aircraft struck treetops.

Final Conclusions

The NTSB determined the probable cause was the captain's intentional descent below the Decision Height (DH). Contributing factors included a breakdown in cockpit resource management (CRM), which prevented the crew from recognizing they were below the glideslope, and the unexplained failure of the GPWS to provide a 'below glideslope' warning. The aircraft struck trees on a ridge 3 nautical miles short of the runway, rolled right, and was destroyed by impact and fire.

Video Analysis

The Deadly Crash Of Buffalo Airways 721 — A detailed look at the 1987 crash of Buffalo Airways Flight 721 near Kansas City, examining the crew's descent below minimums and the failure of safety systems.

If playback is blocked, the owner has disabled embedding — use the link above.

Airframe & Maintenance

Airframe Hours
0
Engines
Pratt & Whitney JT3D-3B

Crew Experience

Captain

Total hours
10,000
On type
3,500

Clarence Brenner, age 52

Systems & Failure Modes

i

GPWS

The Ground Proximity Warning System failed to alert the crew that they were dangerously low and below the glideslope path.

i

ARTS III / MSAW

The ground-based Minimum Safe Altitude Warning system correctly identified the aircraft's low altitude and alerted the controller.

i

ILS

The Instrument Landing System localizer was intercepted, but the crew failed to properly capture or track the glideslope.

Interesting Facts

  • 01The aircraft was a Boeing 707-351C manufactured in 1966.
  • 02The weather at the time of the accident included a 100-foot overcast ceiling and 1/2 mile visibility in fog.
  • 03The aircraft struck a ridge at an elevation of 950 feet while the airport elevation was approximately 1,026 feet.
  • 04The GPWS failed to provide any warning of the unsafe deviation below the glideslope.
  • 05The captain had approximately 10,000 total flying hours, with 3,500 on the Boeing 707.

Safety Actions & Advisories

GPWS Maintenance and Testing

Following the unexplained failure of the GPWS to provide a 'below glideslope' warning, the NTSB emphasized the need for more rigorous testing and maintenance of Ground Proximity Warning Systems to ensure reliability during critical phases of flight.

Location

Near Kansas City, Missouri · 39.2468, -94.7455

ACCIDENT SITE · Coordinates taken from the official investigation report.

Case File History

  1. CorrectionUpdated event timeline.
  2. CorrectionUpdated investigation summary and safety actions.

Related Cases

Case ID · buffalo-airways-721-1987Last updated · Filed

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