King air 200 captain experiences an early descent on the glideslope using the autopilot to fly a cou...

Attributes
ACN	1229938
Time
Date	201501
Local Time Of Day	1201-1800
Place
Locale Reference	CHA.Airport
State Reference	TN
Aircraft 1
Make Model Name	Super King Air 200
Operating Under FAR Part	Part 91
Flight Phase	Final Approach
Route In Use	Other ILS Approach
Flight Plan	IFR
Component
Aircraft Component	Approach Coupler
Person 1
Function	Captain
Qualification	Flight Crew Flight Instructor Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 53 Flight Crew Total 16200 Flight Crew Type 5500
Events
Anomaly	Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Published Material / Policy Deviation - Procedural Clearance Inflight Event / Encounter CFTT / CFIT

Narrative:

When conducting the ILS 20 approach to cha; I was vectored to final by chattanooga approach control. I was given a heading and told to maintain 3000 until passing the daisy outer marker (IAF). I was flying using the autopilot and selected approach mode on the autopilot. The airplane started descent with the glide slope indicator showing slightly below the glide slope. I continued to descend until passing hixon OM; the final approach fix. I realized that I was below the crossing altitude of 2100 feet and stopped my descent. Then shortly thereafter I was told by approach control that they had received a low altitude warning. Thereafter; I broke out of the clouds and landed at cha.

Original NASA ASRS Text

Title: King air 200 Captain experiences an early descent on the glideslope using the autopilot to fly a coupled approach. At the FAF the low condition is detected by the reporter who begins correcting at the same a low altitude alert is received from the Tower. A normal landing ensues.

Narrative: When conducting the ILS 20 approach to CHA; I was vectored to final by Chattanooga approach control. I was given a heading and told to maintain 3000 until passing the Daisy outer marker (IAF). I was flying using the autopilot and selected approach mode on the autopilot. The airplane started descent with the Glide slope indicator showing slightly below the glide slope. I continued to descend until passing Hixon OM; the final approach fix. I realized that I was below the crossing altitude of 2100 feet and stopped my descent. Then shortly thereafter I was told by approach control that they had received a low altitude warning. Thereafter; I broke out of the clouds and landed at CHA.

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.

King air 200 captain experiences an early descent on the glideslope using the autopilot to fly a coupled approach. At the FAF the low condition is detected by the reporter who begins correcting at the same a low altitude alert is received from the tower. A normal landing ensues.