FA10 flight crew reported descending to 800 feet AGL on a visual approach to ftw when the pilot flyi...

Attributes
ACN	1266826
Time
Date	201505
Local Time Of Day	1201-1800
Place
Locale Reference	FTW.Airport
State Reference	TX
Aircraft 1
Make Model Name	Falcon 10/100
Operating Under FAR Part	Part 91
Flight Phase	Initial Approach
Route In Use	Visual Approach
Flight Plan	IFR
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Multiengine Flight Crew Flight Instructor Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 30 Flight Crew Total 14000 Flight Crew Type 2000
Person 2
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Multiengine Flight Crew Flight Instructor Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 30 Flight Crew Total 13000 Flight Crew Type 2000
Events
Anomaly	Deviation - Procedural Published Material / Policy Inflight Event / Encounter CFTT / CFIT

Narrative:

We were on an IFR flight plan; on a visual approach to runway 34; on a wide left base to final. I was using the ILS as a backup to the visual approach. I inappropriately armed the approach mode instead of the localizer mode; and when the glide slope needle started descending; I followed the flight director commands to descend.my copilot protested that something was wrong; and that I should not be descending any lower considering we were now at 800 feet AGL while still 5 miles from the runway. Immediately thereafter the control tower called and asked about our altitude.I immediately climbed back up to 1;500 feet AGL.we did not receive a traffic alert warning system (taws) alert.after landing we discussed that the flight director must have captured a false glide slope; and that I should not have armed the approach mode before being established on the localizer.I believe that a contributing factor was complacency due to the visual conditions.

Original NASA ASRS Text

Title: FA10 flight crew reported descending to 800 feet AGL on a visual approach to FTW when the pilot flying followed a false glideslope.

Narrative: We were on an IFR flight plan; on a visual approach to runway 34; on a wide left base to final. I was using the ILS as a backup to the visual approach. I inappropriately armed the approach mode instead of the localizer mode; and when the glide slope needle started descending; I followed the flight director commands to descend.My copilot protested that something was wrong; and that I should not be descending any lower considering we were now at 800 feet AGL while still 5 miles from the runway. Immediately thereafter the control tower called and asked about our altitude.I immediately climbed back up to 1;500 feet AGL.We did not receive a Traffic Alert Warning System (TAWS) alert.After landing we discussed that the flight director must have captured a false glide slope; and that I should not have armed the approach mode before being established on the localizer.I believe that a contributing factor was complacency due to the visual conditions.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

FA10 flight crew reported descending to 800 feet AGL on a visual approach to ftw when the pilot flying followed a false glideslope.