B737 flight crew reported a navigation malfunction which required them to return to the departure ai...

Attributes
ACN	1514750
Time
Date	201801
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	Climb
Flight Plan	IFR
Component
Aircraft Component	Navigational Equipment and Processing
Person 1
Function	Pilot Not Flying First Officer
Qualification	Flight Crew Instrument Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 42
Person 2
Function	Captain Pilot Flying
Qualification	Flight Crew Instrument Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Altitude Overshoot Deviation - Procedural Published Material / Policy Deviation - Procedural Clearance Deviation - Track / Heading All Types

Narrative:

Departing on the SID the first altitude restriction is 10;000 ft at zzzzz. The captain was pilot flying and prior to zzzzz at about 1 NM VNAV failed along with multiple messages on the mcdu. The captain instructed me to refer to the QRH and while doing that we climbed through our altitude restriction. At 11;000 ft I told departure that we were experiencing navigation issues and were unable to use VNAV. The captain transferred controls to me and I was flying the aircraft while the captain was trying to solve our navigation issues. Working with departure control; we were given vectors to fly while the captain spoke to dispatch. They decided to [advise ATC]; return back to ZZZ and conduct an overweight landing. The captain made a smooth landing and safely taxied to the gate without incident.

Original NASA ASRS Text

Title: B737 flight crew reported a navigation malfunction which required them to return to the departure airport overweight.

Narrative: Departing on the SID the first altitude restriction is 10;000 ft at ZZZZZ. The Captain was Pilot Flying and prior to ZZZZZ at about 1 NM VNAV failed along with multiple messages on the MCDU. The Captain instructed me to refer to the QRH and while doing that we climbed through our altitude restriction. At 11;000 ft I told Departure that we were experiencing NAV issues and were unable to use VNAV. The Captain transferred controls to me and I was flying the aircraft while the Captain was trying to solve our NAV issues. Working with Departure Control; we were given vectors to fly while the Captain spoke to Dispatch. They decided to [advise ATC]; return back to ZZZ and conduct an overweight landing. The Captain made a smooth landing and safely taxied to the gate without incident.

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.