B737 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 134; Flight Crew Total 1337; Flight Crew Type 1337
Distraction; Training / Qualification
Deviation - Altitude Crossing Restriction Not Met; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Human Factors; Environment - Non Weather Related
The Pilot Flying (PF) was flying the LINKK1 arrival to ILS 27 at IAH. The PF initiated a VNAV descent on the LINKK1 and was below path during the arrival. Inside of RDFSH while in VNAV we were cleared for the ILS 27. 1500' was called for and set in MCP. Since we were in VNAV and the step downs were in the legs page; I agreed with this altitude in the MCP. Just inside TRANN the PF asked for approach mode; this disengaged VNAV and since we were below the VNAV path we continued to 1500 no longer protected to 2000' at DENTO or FESTA. We were VMC the entire time and had the airport ad runway insight. ATC issued a low altitude warning. We climbed to 2000' and completed the approach normally.
Pilot reported receiving a low altitude warning from ATC while on the ILS 27 into IAH; which they attributed to the change from VNAV to approach mode.