B737-700 captain reported an automation failure during climb to 15;000 feet at 250 knots on a headin...

Attributes
ACN	1376926
Time
Date	201607
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	Climb
Flight Plan	IFR
Component
Aircraft Component	MCP
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 214
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Altitude Overshoot Deviation - Speed All Types Deviation - Track / Heading All Types

Narrative:

While climbing to 15;000 ft on a heading with a 250 airspeed assignment; the automation started to fail. Aircraft was on autopilot with LNAV and heading control in the climb. For some reason the aircraft accelerated beyond 250 knots. While trying to figure out why; I noticed the aircraft was drifting off heading and then did not reduce pitch approaching 15;000 ft; and I was unable to correct the pitch smoothly to level off on altitude. Finally; I gave up on the automation; I informed ATC of our malfunction and slowly corrected to level flight. I am not sure why the automation failed and the next two flights were uneventful. I briefed the next crews of the problem we had.

Original NASA ASRS Text

Title: B737-700 Captain reported an automation failure during climb to 15;000 feet at 250 knots on a heading. Heading begins to drift and speed increases above 250 knots. While attempting to correct 15;000 feet is exceeded.

Narrative: While climbing to 15;000 ft on a heading with a 250 airspeed assignment; the automation started to fail. Aircraft was on autopilot with LNAV and heading control in the climb. For some reason the aircraft accelerated beyond 250 knots. While trying to figure out why; I noticed the aircraft was drifting off heading and then did not reduce pitch approaching 15;000 ft; and I was unable to correct the pitch smoothly to level off on altitude. Finally; I gave up on the automation; I informed ATC of our malfunction and slowly corrected to level flight. I am not sure why the automation failed and the next two flights were uneventful. I briefed the next Crews of the problem we had.

Data retrieved from NASA's ASRS site 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.

B737-700 captain reported an automation failure during climb to 15;000 feet at 250 knots on a heading. Heading begins to drift and speed increases above 250 knots. While attempting to correct 15;000 feet is exceeded.