B737 captain reported descending below a 'descend via' crossing restriction when the crew failed to ...

Attributes
ACN	1303080
Time
Date	201510
Place
Locale Reference	EWR.Airport
State Reference	NJ
Aircraft 1
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Route In Use	STAR PHLBO3
Flight Plan	IFR
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 114 Flight Crew Type 1237
Events
Anomaly	Deviation - Altitude Crossing Restriction Not Met Deviation - Altitude Overshoot Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Inflight Event / Encounter Weather / Turbulence

Narrative:

We were given 'descend via the phlbo arrival' from washington center which meant to descend to 8000 ft while crossing certain fixes at or above specific altitudes. On the descent outside of stefe intersection on the phlbo arrival; we were encountering moderate turbulence. At some point when given 'descend via' on the arrival to 8000 ft; I didn't notice we left VNAV mode on the MCP in the descent while in the midst of asking the flight attendants to take their jump seats. The non-flying pilot was also occupied with washington center trying to get clearance to deviate around weather. Approaching stefe; the restriction was to cross stefe at or above 13;000 ft. Since the MCP was in lvl chg mode due to my oversight; we were unfortunately at 9500 ft. Washington center noted that we were 3500 ft lower than we were supposed to be.

Original NASA ASRS Text

Title: B737 Captain reported descending below a 'descend via' crossing restriction when the crew failed to note they were in Level Change rather than VNAV mode.

Narrative: We were given 'descend via the PHLBO arrival' from Washington Center which meant to descend to 8000 ft while crossing certain fixes at or above specific altitudes. On the descent outside of STEFE intersection on the PHLBO arrival; we were encountering moderate turbulence. At some point when given 'descend via' on the arrival to 8000 ft; I didn't notice we left VNAV mode on the MCP in the descent while in the midst of asking the flight attendants to take their jump seats. The non-flying pilot was also occupied with Washington Center trying to get clearance to deviate around weather. Approaching STEFE; the restriction was to cross STEFE at or above 13;000 ft. Since the MCP was in LVL CHG mode due to my oversight; we were unfortunately at 9500 ft. Washington Center noted that we were 3500 ft lower than we were supposed to be.

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 captain reported descending below a 'descend via' crossing restriction when the crew failed to note they were in level change rather than VNAV mode.