PC12 captain experiences an autopilot malfunction during the teb 6 departure; resulting in a track d...

Narrative:

[We were] cleared for teb 6 SID runway 24 at teb [and] programmed [the] SID into the FMS. Normal departure out of teb [and] at 1;000 ft AGL engaged the autopilot. Autopilot flew the SID properly [and] leveled off 1;500 ft on a 240 degree heading. Autopilot turned aircraft towards 280 degree heading; but failed to stop and continued another 20-30 degrees. I disconnected autopilot immediately to turn back to 280 degree heading. At the same time ATC instructed us to expedite climb to 6;000 ft. My first officer answered the call and I began to climb. In the same transmission ATC also instructed us to turn right direct to brezy. My first officer responded to that and directed the FMS to take us to brezy. As we made the turn and climb; ATC questioned us as to where we were going and [told us] that we should be on a 280 degree heading. I immediately turned back to 280 degrees. My first officer responded; 'you gave us direct to brezy.' ATC responded that he was sorry he missed the incorrect read back and not to worry; it was his mistake. He said he had asked us to expedite the climb and to 'expect a right turn direct brezy.' a contributing factor to the miscommunication was the busyness of the frequency workload on the controller; the aural warning of the autopilot disconnect causing additional noise in the headset for my first officer; as well as the FMS and autopilot incorrectly flying the SID. A corrective action would be for ATC not to accept an incorrect read back in such a crucial phase of flight. I will [also] hand fly the SID form now on. Discouraging as it is; I will not trust the approved FMS and autopilot to actually fly the SID. Had this situation not occurred at this inopportune time; both my first officer and I would have taken a moment to question the instructions given.

Original NASA ASRS Text

Title: PC12 Captain experiences an autopilot malfunction during the TEB 6 departure; resulting in a track deviation. A second deviation occurs when the crew is told to expect direct BREZY and reads back cleared direct BREZY.

Narrative: [We were] cleared for TEB 6 SID Runway 24 at TEB [and] programmed [the] SID into the FMS. Normal departure out of TEB [and] at 1;000 FT AGL engaged the autopilot. Autopilot flew the SID properly [and] leveled off 1;500 FT on a 240 degree heading. Autopilot turned aircraft towards 280 degree heading; but failed to stop and continued another 20-30 degrees. I disconnected autopilot immediately to turn back to 280 degree heading. At the same time ATC instructed us to expedite climb to 6;000 FT. My First Officer answered the call and I began to climb. In the same transmission ATC also instructed us to turn right direct to BREZY. My First Officer responded to that and directed the FMS to take us to BREZY. As we made the turn and climb; ATC questioned us as to where we were going and [told us] that we should be on a 280 degree heading. I immediately turned back to 280 degrees. My First Officer responded; 'You gave us direct to BREZY.' ATC responded that he was sorry he missed the incorrect read back and not to worry; it was his mistake. He said he had asked us to expedite the climb and to 'expect a right turn direct BREZY.' A contributing factor to the miscommunication was the busyness of the frequency workload on the Controller; the aural warning of the autopilot disconnect causing additional noise in the headset for my First Officer; as well as the FMS and autopilot incorrectly flying the SID. A corrective action would be for ATC not to accept an incorrect read back in such a crucial phase of flight. I will [also] hand fly the SID form now on. Discouraging as it is; I will not trust the approved FMS and autopilot to actually fly the SID. Had this situation not occurred at this inopportune time; both my First Officer and I would have taken a moment to question the instructions given.

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	967487
Time
Date	201108
Local Time Of Day	1201-1800
Place
Locale Reference	TEB.Airport
State Reference	NJ
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	PC-12
Operating Under FAR Part	Part 91
Flight Phase	Climb
Route In Use	SID TEB 6
Flight Plan	IFR
Component
Aircraft Component	Autopilot
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Instrument Flight Crew Flight Instructor Flight Crew Commercial
Experience	Flight Crew Last 90 Days 140 Flight Crew Total 4600 Flight Crew Type 2000
Events
Anomaly	ATC Issue All Types Aircraft Equipment Problem Less Severe Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Deviation - Track / Heading All Types

PC12 captain experiences an autopilot malfunction during the teb 6 departure; resulting in a track deviation. A second deviation occurs when the crew is told to expect direct brezy and reads back cleared direct brezy.