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Gulfstream III N85VT

Accident Case Study

This crew dialed the ILS frequency in the standby position while using the VOR for long range navigation, both neglected to select the ILS frequency prior to starting the approach. When they were unable to select APR with their flight directors, the failed to investigate why. The pilot then started to fly the VOR as if it were the localizer. The airplane's EADI had the fast/slow pointer on the left and the glide slope pointer on the right, both presented in the same color.



Figure: Diagram of the EADI, from NTSB Report, Figure 4


Figure: Accident Airplane's Altitude Profile, from NTSB Report, Figure 3

Accident Report

  • Date: 22 NOV 2004
  • Time: 06:15
  • Type: Gulfstream Aerospace G-1159A Gulfstream III
  • Operator: Business Jet Services
  • Registration: N85VT
  • Fatalities: 3 of 3 crew
  • Aircraft Fate: Destroyed
  • Phase: Approach
  • Airports: (Departure) Dallas-Love Field, TX (DAL) (DAL/KDAL), United States of America; (Destination) Houston-William P. Hobby Airport, TX (HOU) (HOU/KHOU), United States of America


The airplane was on an ILS approach to runway 04 when it struck a light pole adjacent to a roadway and crashed into a field. Just prior to the crash the air traffic controller had warned the crew: "Gulfstream eight five victor tango, check your altitude, altitude indicates four hundred feet."

The METAR around the time of the accident read: KHOU 221253Z 12005KT 1/8SM BR BKN001 BKN006 OVC050 22/22 A3002 (wind 120 degrees at 5kts, visibility 1/8nm/230 m, mist 5-7 oktas cloud at 100ft, 5-7 oktas cloud at 600ft, 8 oktas overcast cloud at 5000ft, temperature 22C, dewpoint 22C, QNH 30.02in)

Probable Cause

"The National Transportation Safety Board determines that the probable cause of this accident was the flight crew’s failure to adequately monitor and cross-check the flight instruments during the approach. Contributing to the accident was the flight crew’s failure to select the instrument landing system frequency in a timely manner and to adhere to approved company approach procedures, including the stabilized approach criteria."

See Also:

Stabilized Approach


Aviation Safety Network

NTSB Aircraft Accident Brief, AAB-06/06, Crash During Approach to Landing, Business Jet Services, Ltd., Gulfstream G-1159A (GIII), N85VT, Houston, Texas, November 22, 2004

Revision: 20120406