<< >> NASA ASRS Report 430866, March 1999

Flight crew of an mdt turboprop overshot assigned intermediate altitude during climb due to improper setting of the autoplt preselect altitude and no warning from the altitude alert system.

Attributes
ACN	430866
Time
Date	199903
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : dhp.vortac
State Reference	FL
Altitude	msl bound lower : 13000 msl bound upper : 13700
Environment
Light	Daylight
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 240 flight time total : 9000 flight time type : 3000
ASRS Report	430866
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : multi engine
Experience	flight time last 90 days : 210 flight time total : 11000 flight time type : 5000
ASRS Report	431420
Events
Anomaly	altitude deviation : overshoot non adherence : far non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to assigned airspace
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

While climbing to 11000 ft we received a climb clearance to 13000 ft. At 10700 ft we reset the altitude selector for the autoplt to 13000 ft. Within this 300 ft window, the transition must have created a fault in the altitude capture mode to the autoplt. I switched over to the #2 radio to pick up mia ATIS. The aircraft climbed through the assigned altitude of 13000 ft to 13700 ft before I realized 13000 ft was still in the altitude select and we had not been given a higher altitude. We immediately returned to altitude 13000 ft with no conflicts noted and no warnings from ATC of any problems. The altitude warning never sounded. Supplemental information from acn 431420: no mention of the deviation was made by ATC and our TCASII showed no traffic upon arriving at all other preselected altitudes. The altitude preselect triggered the autoplt to capture the altitude without a glitch. I believe that because of our extremely slow climb the autoplt could not 'see' our intentions and did not capture as it was supposed to.

Related reports:

• Flight crew of an mdt turboprop on VFR departure was alerted...

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Original NASA ASRS Text

Title: FLC OF AN MDT TURBOPROP OVERSHOT ASSIGNED INTERMEDIATE ALT DURING CLB DUE TO IMPROPER SETTING OF THE AUTOPLT PRESELECT ALT AND NO WARNING FROM THE ALT ALERT SYS.

Narrative: WHILE CLBING TO 11000 FT WE RECEIVED A CLB CLRNC TO 13000 FT. AT 10700 FT WE RESET THE ALT SELECTOR FOR THE AUTOPLT TO 13000 FT. WITHIN THIS 300 FT WINDOW, THE TRANSITION MUST HAVE CREATED A FAULT IN THE ALT CAPTURE MODE TO THE AUTOPLT. I SWITCHED OVER TO THE #2 RADIO TO PICK UP MIA ATIS. THE ACFT CLBED THROUGH THE ASSIGNED ALT OF 13000 FT TO 13700 FT BEFORE I REALIZED 13000 FT WAS STILL IN THE ALT SELECT AND WE HAD NOT BEEN GIVEN A HIGHER ALT. WE IMMEDIATELY RETURNED TO ALT 13000 FT WITH NO CONFLICTS NOTED AND NO WARNINGS FROM ATC OF ANY PROBS. THE ALT WARNING NEVER SOUNDED. SUPPLEMENTAL INFO FROM ACN 431420: NO MENTION OF THE DEV WAS MADE BY ATC AND OUR TCASII SHOWED NO TFC UPON ARRIVING AT ALL OTHER PRESELECTED ALTS. THE ALT PRESELECT TRIGGERED THE AUTOPLT TO CAPTURE THE ALT WITHOUT A GLITCH. I BELIEVE THAT BECAUSE OF OUR EXTREMELY SLOW CLB THE AUTOPLT COULD NOT 'SEE' OUR INTENTIONS AND DID NOT CAPTURE AS IT WAS SUPPOSED TO.

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.