An air carrier large transport flight crew misuses the autoflt system when they select the wrong mode and set the altitude below the clearance limit. The aircraft descends below their assigned altitude.

Home

Browse by month

Random

Latest

About

Contact

Attributes
ACN	343220
Time
Date	199607
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : yyz
State Reference	ON
Altitude	msl bound lower : 11000 msl bound upper : 13000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : czyz
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	arrival other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : cfi pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 210 flight time total : 7000 flight time type : 330
ASRS Report	343220
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : crossing restriction not met altitude deviation : overshoot non adherence : clearance non adherence : far other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other controllera other flight crewa
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

While descending into yyz we were cleared to cross ywt below 17000 ft above 13000 ft. We were in VNAV and the captain switch to flch. The mode control panel had 11000 ft in it for the next fix. Due to selecting flch, the aircraft left 13000 ft for 11000 ft. We should have left it in VNAV, but the captain thought we were high since we had had our speed up en route.

Original NASA ASRS Text

Title: AN ACR LGT FLC MISUSES THE AUTOFLT SYS WHEN THEY SELECT THE WRONG MODE AND SET THE ALT BELOW THE CLRNC LIMIT. THE ACFT DSNDS BELOW THEIR ASSIGNED ALT.

Narrative: WHILE DSNDING INTO YYZ WE WERE CLRED TO CROSS YWT BELOW 17000 FT ABOVE 13000 FT. WE WERE IN VNAV AND THE CAPT SWITCH TO FLCH. THE MODE CTL PANEL HAD 11000 FT IN IT FOR THE NEXT FIX. DUE TO SELECTING FLCH, THE ACFT LEFT 13000 FT FOR 11000 FT. WE SHOULD HAVE LEFT IT IN VNAV, BUT THE CAPT THOUGHT WE WERE HIGH SINCE WE HAD HAD OUR SPD UP ENRTE.

Data retrieved from NASA's ASRS site as of July 2007 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.