A B757-200 flight crew; cleared to cross jenfr at 4;100 ft and; shortly after; cleared for the ILS 3...

Narrative:

We were on pre-final vectors. We were [then cleared direct jenfr;] 'cross jenfr at 4;100.' both PF and pm confirmed that restriction was in the mcdu. PF switched to flch to expedite descent. Subsequently given 'cleared for the ILS runway 30.' the PF put 2;500 in the MCP. Just prior to jenfr; we noticed aircraft descending through 4;100. Autopilot was disconnected by PF. Aircraft was leveled off at 3;850. We crossed jenfr a few seconds later; and continued our descent and approach. Nothing said by ATC. Switching out of VNAV with its inherent increased protection; and then subsequently setting a new altitude in the MCP...obviously flch will not honor the restriction in the mcdu. Not catching the flch mode by the pm was also a cause.[to avoid this in the future:] don't set the MCP window lower or higher than a restriction when operating in flch. Quicker/more accurate cross checking by the pm.

Original NASA ASRS Text

Title: A B757-200 flight crew; cleared to cross JENFR at 4;100 FT and; shortly after; cleared for the ILS 30 at OAK descended below the restriction when the PF entered the glideslope intercept altitude in the altitude alert window while operating in FLCH mode vice VNAV as intended.

Narrative: We were on pre-final vectors. We were [then cleared direct JENFR;] 'cross JENFR at 4;100.' Both PF and PM confirmed that restriction was in the MCDU. PF switched to FLCH to expedite descent. Subsequently given 'cleared for the ILS Runway 30.' The PF put 2;500 in the MCP. Just prior to JENFR; we noticed aircraft descending through 4;100. Autopilot was disconnected by PF. Aircraft was leveled off at 3;850. We crossed JENFR a few seconds later; and continued our descent and approach. Nothing said by ATC. Switching out of VNAV with its inherent increased protection; and then subsequently setting a new altitude in the MCP...Obviously FLCH will not honor the restriction in the MCDU. Not catching the FLCH mode by the PM was also a cause.[To avoid this in the future:] Don't set the MCP window lower or higher than a restriction when operating in FLCH. Quicker/More Accurate cross checking by the PM.

Data retrieved from NASA's ASRS site as of July 2013 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	1130621
Time
Date	201311
Local Time Of Day	0601-1200
Place
Locale Reference	NCT.TRACON
State Reference	CA
Environment
Flight Conditions	Marginal
Aircraft 1
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Route In Use	Vectors
Flight Plan	IFR
Component
Aircraft Component	FMS/FMC
Person 1
Function	First Officer Pilot Not Flying
Events
Anomaly	Deviation - Altitude Crossing Restriction Not Met Deviation - Altitude Overshoot Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy

A B757-200 flight crew; cleared to cross jenfr at 4;100 ft and; shortly after; cleared for the ILS 30 at oak descended below the restriction when the PF entered the glideslope intercept altitude in the altitude alert window while operating in flch mode vice VNAV as intended.