CL600 first officer disengages autopilot at FL370 in order to increase turn rate.

Attributes
ACN	735487
Time
Date	200704
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : zmp.artcc
State Reference	MN
Altitude	msl single value : 37000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zmp.artcc
Operator	general aviation : corporate
Make Model Name	Challenger CL600
Operating Under FAR Part	Part 91
Navigation In Use	other
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : corporate
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 12500 flight time type : 1100
ASRS Report	735437
Person 2
Affiliation	company : corporate government : faa
Function	controller : radar flight crew : first officer
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : far
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to assigned altitude
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

While in cruise at FL370 eastbound; we were given a heading of 010 degree vector by the center controller at the request of the next controller. I read back the heading and asked the controller to confirm the 010 degree heading. The controller then confirmed the heading and asked we do it now. The PF had already began the turn; but then disengaged the autoplt system and attempted to increase the rate of turn while hand flying. When doing this; the aircraft began a climb to FL372 altitude. The controller did not question our altitude and I believe the deviation did not exceed rvsm limitations. I discussed with the PF the requirement for use of autoplt in rvsm airspace and the altitude limitations in that airspace. The PF has been previously trained in rvsm procedures. He stated he wanted to help the controller by increasing the turn rate.

Original NASA ASRS Text

Title: CL600 FO DISENGAGES AUTOPILOT AT FL370 IN ORDER TO INCREASE TURN RATE.

Narrative: WHILE IN CRUISE AT FL370 EBOUND; WE WERE GIVEN A HDG OF 010 DEG VECTOR BY THE CTR CTLR AT THE REQUEST OF THE NEXT CTLR. I READ BACK THE HDG AND ASKED THE CTLR TO CONFIRM THE 010 DEG HDG. THE CTLR THEN CONFIRMED THE HDG AND ASKED WE DO IT NOW. THE PF HAD ALREADY BEGAN THE TURN; BUT THEN DISENGAGED THE AUTOPLT SYS AND ATTEMPTED TO INCREASE THE RATE OF TURN WHILE HAND FLYING. WHEN DOING THIS; THE ACFT BEGAN A CLB TO FL372 ALT. THE CTLR DID NOT QUESTION OUR ALT AND I BELIEVE THE DEV DID NOT EXCEED RVSM LIMITATIONS. I DISCUSSED WITH THE PF THE REQUIREMENT FOR USE OF AUTOPLT IN RVSM AIRSPACE AND THE ALT LIMITATIONS IN THAT AIRSPACE. THE PF HAS BEEN PREVIOUSLY TRAINED IN RVSM PROCS. HE STATED HE WANTED TO HELP THE CTLR BY INCREASING THE TURN RATE.

Data retrieved from NASA's ASRS site as of January 2009 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.