Narrative:

Near the metropolitan fix at 3;000 feet [and] 250 kts with autopilot engaged in LNAV altitude hold; while transitioning from the PHLBO3 STAR to the ILS runway 4R approach into ewr; the approach controller initially gave us direct to the grity if and cleared us for the approach; maintain 3000 feet until established. We used LNAV to go direct to grity; selected the app mode; began to slow down and selected flaps 5.a few miles from grity; the controller gave us a left heading to vector us just outside the FAF; doins; and told us to maintain 2;000 feet until established and 190 kts or more until doins. Since [we were] in a 737 with lower maximum flaps speeds; at a light weight; and with engine anti-ice on; we knew we would have a difficult time slowing and descending. PF (pilot flying) selected heading sel for the new vector. Pm (pilot monitoring) selected 2;000 feet on the MCP and the PF selected lvl chg and 190 kts. After some discussion on how it would be difficult to slow; PF requested flaps 10; gear down and extended the speed brakes. VOR localizer captured just outside of the FAF. PF selected target speed. As PF; I was fixated on the airspeed that was not decreasing and waiting for the next flap setting speeds. F15; 25 and 30 were selected. Both PF and pm believed that GS had captured; but it had not and we were still in lvl chg. Pm incorrectly set tdze. PF was fixated on the air speeds. We changed to tower frequency and checked in. [The] aircraft was still lvl chg and tdze in the MCP (mode control panel) altitude [and] the aircraft descended below glideslope. After the 1;000 feet callout both the PF and pm began to realize that we were below GS. At the same time the tower said that we were low altitude and should be at 1;700 feet. Our altitude was going through 900 feet. PF disconnected the ap (autopilot) and added power and climbed immediately back to the glide path. Though unstable at 1;000 feet we were stable at 500 feet and continued to land.

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Original NASA ASRS Text

Title: B737 First Officer reported descending below glideslope due to inappropriate automation settings while on the ILS Runway 4R approach into EWR.

Narrative: Near the METRO fix at 3;000 feet [and] 250 kts with autopilot engaged in LNAV ALT HOLD; while transitioning from the PHLBO3 STAR to the ILS Runway 4R approach into EWR; the Approach Controller initially gave us direct to the GRITY IF and cleared us for the approach; maintain 3000 feet until established. We used LNAV to go direct to GRITY; selected the APP mode; began to slow down and selected flaps 5.A few miles from GRITY; the Controller gave us a left heading to vector us just outside the FAF; DOINS; and told us to maintain 2;000 feet until established and 190 kts or more until DOINS. Since [we were] in a 737 with lower maximum flaps speeds; at a light weight; and with engine anti-ice on; we knew we would have a difficult time slowing and descending. PF (Pilot Flying) selected HDG SEL for the new vector. PM (Pilot Monitoring) selected 2;000 feet on the MCP and the PF selected LVL CHG and 190 kts. After some discussion on how it would be difficult to slow; PF requested flaps 10; gear down and extended the speed brakes. VOR LOC captured just outside of the FAF. PF selected target speed. As PF; I was fixated on the airspeed that was not decreasing and waiting for the next flap setting speeds. F15; 25 and 30 were selected. Both PF and PM believed that GS had captured; but it had not and we were still in LVL CHG. PM incorrectly set TDZE. PF was fixated on the air speeds. We changed to Tower frequency and checked in. [The] aircraft was still LVL CHG and TDZE in the MCP (Mode Control Panel) altitude [and] the aircraft descended below glideslope. After the 1;000 feet callout both the PF and PM began to realize that we were below GS. At the same time the Tower said that we were low altitude and should be at 1;700 feet. Our altitude was going through 900 feet. PF disconnected the AP (Autopilot) and added power and climbed immediately back to the glide path. Though unstable at 1;000 feet we were stable at 500 feet and continued to land.

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.