On climb the performance management system defaulted to the autoplt vertical speed logic which requi...

Attributes
ACN	278353
Time
Date	199407
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : adm
State Reference	OK
Altitude	msl bound lower : 32000 msl bound upper : 32000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zfw tower : dfw
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument pilot : atp
Experience	flight time last 90 days : 150 flight time total : 3800 flight time type : 1300
ASRS Report	278353
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe other anomaly other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course flight crew : regained aircraft control flight crew : overcame equipment problem
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation other

Narrative:

This event occurred during climb out with excellent WX conditions. The autoplt had been engaged at 15000 ft with perf and navigation mode selected. It appeared to be functioning well. Not much was occurring in the cockpit, and the captain began his PA's to the passenger. I opened my charts up to review destination approachs, as it had been a while since I'd been to pdx. I felt a vibration, looked up, and noticed my airspeed had deteriorated and the FMA indicated 'speed low.' I immediately clicked off the autoplt, verified mlt power, and leveled the wings, I asked the captain to ask ATC for a descent and it was approved. I slowly rebuilt airspeed, and with center approval, resumed the climb out. The aircraft never stalled, but it was literally only a few seconds/KTS from doing so. Somehow, the perf mode had deselected during the climb, and it fails into the vertical speed regime. The climb rate the autoplt had when perf deselected nearly resulted in a stall, as the aircraft bled its speed to maintain the climb. My failure to maintain an adequate scan was the primary cause of this near stall incident. I relied too much on the autoplt, and allowed myself to become distracted with my chart review. That should have been done at cruise, with the captain 'covering' for me while I had my head in the books. Also, the PNF might have noticed low speed sooner if he'd made his PA at level off, not in the climb. I'll never underestimate the potential for disaster that over-reliance on an autoplt holds again.

Original NASA ASRS Text

Title: ON CLB THE PERFORMANCE MGMNT SYS DEFAULTED TO THE AUTOPLT VERT SPD LOGIC WHICH REQUIRED THE GIVEN VERT SPD AT THE EXPENSE OF AIRSPD. THE CREW DID NOT NOTICE THE SPD DETERIORATION UNTIL ACFT COMMENCED VIBRATION AT THE BEGINNING OF THE STALL.

Narrative: THIS EVENT OCCURRED DURING CLBOUT WITH EXCELLENT WX CONDITIONS. THE AUTOPLT HAD BEEN ENGAGED AT 15000 FT WITH PERF AND NAV MODE SELECTED. IT APPEARED TO BE FUNCTIONING WELL. NOT MUCH WAS OCCURRING IN THE COCKPIT, AND THE CAPT BEGAN HIS PA'S TO THE PAX. I OPENED MY CHARTS UP TO REVIEW DEST APCHS, AS IT HAD BEEN A WHILE SINCE I'D BEEN TO PDX. I FELT A VIBRATION, LOOKED UP, AND NOTICED MY AIRSPD HAD DETERIORATED AND THE FMA INDICATED 'SPD LOW.' I IMMEDIATELY CLICKED OFF THE AUTOPLT, VERIFIED MLT PWR, AND LEVELED THE WINGS, I ASKED THE CAPT TO ASK ATC FOR A DSCNT AND IT WAS APPROVED. I SLOWLY REBUILT AIRSPD, AND WITH CTR APPROVAL, RESUMED THE CLBOUT. THE ACFT NEVER STALLED, BUT IT WAS LITERALLY ONLY A FEW SECONDS/KTS FROM DOING SO. SOMEHOW, THE PERF MODE HAD DESELECTED DURING THE CLB, AND IT FAILS INTO THE VERT SPD REGIME. THE CLB RATE THE AUTOPLT HAD WHEN PERF DESELECTED NEARLY RESULTED IN A STALL, AS THE ACFT BLED ITS SPD TO MAINTAIN THE CLB. MY FAILURE TO MAINTAIN AN ADEQUATE SCAN WAS THE PRIMARY CAUSE OF THIS NEAR STALL INCIDENT. I RELIED TOO MUCH ON THE AUTOPLT, AND ALLOWED MYSELF TO BECOME DISTRACTED WITH MY CHART REVIEW. THAT SHOULD HAVE BEEN DONE AT CRUISE, WITH THE CAPT 'COVERING' FOR ME WHILE I HAD MY HEAD IN THE BOOKS. ALSO, THE PNF MIGHT HAVE NOTICED LOW SPD SOONER IF HE'D MADE HIS PA AT LEVEL OFF, NOT IN THE CLB. I'LL NEVER UNDERESTIMATE THE POTENTIAL FOR DISASTER THAT OVER-RELIANCE ON AN AUTOPLT HOLDS AGAIN.

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.

On climb the performance management system defaulted to the autoplt vertical speed logic which required the given vertical speed at the expense of airspeed. The crew did not notice the speed deterioration until aircraft commenced vibration at the beginning of the stall.