Narrative:

Glass cockpit B767 at near max landing weight. I was PF and had joined final approach course at 3000 ' outside of wugal in night IMC to the VOR/DME 22L at jfk. The autopilot was engaged and assigned airspeed was 170. Approach clearance was received in the following manor. 'Decend to 2;000 ft cleared VOR/DME 22L'. Since flaps were extended and I was in approach mode on a segment of the approach; I selected VNAV and intervene with speed. PNF had set 2;000 ft in the MCP and I made the point that we could now set FAF altitude. PNF agreed and set 1;400 ft. Since we were below the vertical path; my plan was to allow VNAV to intercept the path from below; but the PNF made the comment that we had to leave 3;000 ft based upon the clearance. After a second of thought I decided that he was technically correct; even though I didn't think it mattered to the controller. I needed a different mode to begin the descent per clearance and flch was selected. The subsequent request of the controller to further reduce speed kept us busy configuring to gear down and final flaps to accommodate. It was a reasonably slow descent but reaching 2;000 ft there was no sign of level off and all three pilots verbalized it. Before we were 100 ft off altitude; I recognized the problem and told the PNF to reset 2;000 ft in the MCP and I re-punched the flch button to make sure it knew to fly up instead of down. I was reluctant to disengage the ap if there was any alternative due to the precision required. The ap was initially slower than I expected to reverse the vertical path. I saw below 1;800 ft and airspeed at vref when the automation aggressively added lots of power and pitched up. Soon we were blasting through 2;000 ft at a pitch in excess of 10 degrees and I knew I had to disengage the autopilot. I got it stabilized below 2;300 ft and a little right of course correcting back. I then reselected ap and reprogrammed the MCP. This time I stayed in VNAV a little above 2;200 ft and allowed it to intercept the vertical path from that altitude. Soon the FAF was active and rounded up MDA was selected in the MCP. The approach was stable and I continued to an uneventful landing. Sometimes I wonder if our training; in its attempt to reduce mental gymnastics by supplying rules of thumb about when to select various buttons; is doing us a disservice because of the many ways a clearance can be delivered. Have we thought of all the different twists?

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Original NASA ASRS Text

Title: B767 Flight Crew reports descending below an intermediate approach segment altitude while attempting to use LNAV and VNAV to fly the VOR DME Runway 22 approach at JFK. The MCP altitude was set to 1400 feet prior to WUGAL; allowing the aircraft to descend below 2000 feet prematurely. Altitude is quickly corrected and flight continues to landing.

Narrative: Glass cockpit B767 at near max landing weight. I was PF and had joined final approach course at 3000 ' outside of WUGAL in night IMC to the VOR/DME 22L at JFK. The autopilot was engaged and assigned airspeed was 170. Approach clearance was received in the following manor. 'Decend to 2;000 ft cleared VOR/DME 22L'. Since flaps were extended and I was in approach mode on a segment of the approach; I selected VNAV and intervene with speed. PNF had set 2;000 ft in the MCP and I made the point that we could now set FAF altitude. PNF agreed and set 1;400 ft. Since we were below the vertical path; my plan was to allow VNAV to intercept the path from below; but the PNF made the comment that we had to leave 3;000 ft based upon the clearance. After a second of thought I decided that he was technically correct; even though I didn't think it mattered to the controller. I needed a different mode to begin the descent per clearance and FLCH was selected. The subsequent request of the controller to further reduce speed kept us busy configuring to gear down and final flaps to accommodate. It was a reasonably slow descent but reaching 2;000 ft there was no sign of level off and all three pilots verbalized it. Before we were 100 ft off altitude; I recognized the problem and told the PNF to reset 2;000 ft in the MCP and I re-punched the FLCH button to make sure it knew to fly up instead of down. I was reluctant to disengage the AP if there was any alternative due to the precision required. The AP was initially slower than I expected to reverse the vertical path. I saw below 1;800 ft and airspeed at Vref when the automation aggressively added lots of power and pitched up. Soon we were blasting through 2;000 ft at a pitch in excess of 10 degrees and I knew I had to disengage the autopilot. I got it stabilized below 2;300 ft and a little right of course correcting back. I then reselected AP and reprogrammed the MCP. This time I stayed in VNAV a little above 2;200 ft and allowed it to intercept the vertical path from that altitude. Soon the FAF was active and rounded up MDA was selected in the MCP. The approach was stable and I continued to an uneventful landing. Sometimes I wonder if our training; in its attempt to reduce mental gymnastics by supplying rules of thumb about when to select various buttons; is doing us a disservice because of the many ways a clearance can be delivered. Have we thought of all the different twists?

Data retrieved from NASA's ASRS site as of April 2012 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.