B767-300 and 300 ER
Flight Crew Commercial
Situational Awareness; Human-Machine Interface; Communication Breakdown
Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew FLC Overrode Automation; Flight Crew Returned To Clearance
Aircraft; Human Factors; Procedure
The Captain was pilot flying as we flew the Clare RNAV SID off Runway 17R from DFW and during the turn toward SWB over TREXX he selected HDG Select Mode rather than LNAV. I told him he was in heading select and called out [the resulting] deviation from the SID track. The Captain said he was worried about the bank angle LNAV was using and went to HDG select to reduce it (LNAV was using a 25-30 degree bank and IAS was 246-248 KTS at a weight of about 400;000 pounds with the flaps up). We were approximately 1.5 miles off the LNAV course at our furthest point before correcting back to course. ATC made no comment about the deviation.
After taking off Runway 17R at DFW; the jet was having difficulty making the at/above 5;000 FT crossing restriction at TREXX (not to exceed 240 KTS) with the flaps up. We barely made the required crossing restriction; but then--because of the nearly 90 degree turn required over TREXX to intercept the course towards JOLEN--to prevent the jet from dangerously approaching stall buffet (the airspeed readout was flashing intermittently at this time) I elected to select a bank angle limit of five degrees and; as we accelerated; 10 degrees (less than a standard rate turn) to prevent the airspeed from bleeding off below 240 KTS. Consequently we began to track off the magenta line outside of course to the south reaching a maximum distance of 1.5 NM off track before reacquiring the magenta line track.The First Officer was advising me of the deviations as I was making the turn. It was VFR and there were no apparent conflicts or TCAS alerts. The First Officer never advised the Controller of the deviation; or requested course relief; but instead kept advising me of the track deviations.In retrospect; it would have been better to have left the flaps at one degree until after passing TREXX and making the turn towards JOLEN as well as advising ATC and requesting the necessary required relief. Having not flown the 767-300 in over a month due to being on vacation also contributed to my rusty airmanship.
When faced with a pilot induced need to choose between track perfection versus avoiding an approach to a stall while flying the CLARE RNAV SID off Runway 17R at DFW; the Captain chose the latter and limited bank angle to avoid a flaps up approach to a stall. The First Officer and Relief Pilot worried over; and continually reminded the Captain; of the resultant track deviation.