B737 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 198; Flight Crew Type 824
Situational Awareness
Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Became Reoriented
Human Factors
I was practicing a HUD Takeoff. Upon throttle up to takeoff thrust; I remember depressing the Takeoff/Go-around (TO/GA) button. However; I must not have depressed it completely as my HUD display commanded much too high of a pitch angle. As the airspeed bled off; both my FO and I noticed; and mentioned that something wasn't right. I felt that the deck angle was far too high and the HUD was commanding an even higher pitch. I began to lower the nose. At the same time; my FO told me to lower the nose. The stick shaker activated for a second or two after which the pitch angle was brought to an acceptable level. We then continued normal operations without the use of the HUD.A quick up and down crosscheck from HUD to the lower flight director at the first sign of an anomaly could've prevented stick shaker activation.
The Captain made me aware at the outset he was a relatively new company Captain and didn't have much experience in [this model B737]. He had been practicing his HUD takeoff procedures lately and briefed he would perform one for our takeoff. We set up the instruments accordingly and the preflight; engine start; and taxi proceeded normally.The takeoff started out uneventfully but immediately after liftoff I noticed there was no FD displayed on either ADI. Just prior to raising the gear handle; I engaged Takeoff/Go-Around (TO/GA) to get the FD to come up. Initially the Captain brought the pitch indicator up into the command bars but then steadily continued to raise the pitch higher. I didn't react initially; knowing the command bars tend to fluctuate and can be inaccurate in [this model B737]; but I became concerned and spoke up when the airspeed slid back to V2 and then slightly below. I believe I said something like 'you're getting a little slow'. The airspeed froze for a second or two but the PF did not lower the nose at all and may have even raised it slightly.As airspeed continued to deteriorate I told him he needed to get the nose down. When he didn't seem to respond I began to apply forward pressure on the yoke and repeat the need to lower the nose. I can't recall what our lowest speed was but it was significantly lower than V2. That's when the stick shaker came alive; which certainly got the PF's attention; and he lowered the nose enough get out of stick shaker. At that point he said the HUD was giving bad guidance and stowed it. I told him to lower the nose further to build more airspeed as he started a turn for the departure. We retracted the flaps as the aircraft accelerated and climbed normally and the rest of the flight was uneventful.I can't speak to the HUD since I have no experience and little knowledge of that system. I wonder if selecting TO/GA after getting airborne had a negative effect its operation? But based on the actions of the Captain it's obvious he was very focused on whatever pitch guidance the HUD was providing and did not notice our negative aircraft state. Without a doubt; my fault was not being assertive soon enough to correct the situation before it became a bad situation. I saw the event developing and I didn't realize quickly enough that the Captain had become fixated and had lost situational awareness on what the aircraft was doing. I attempted to intervene; but it was too little too late to avoid getting to the point of stall indicator activation. I knew he was a new Captain; still getting used to a new system; and I should have been better prepared to proactively intervene as soon as the aircraft was approaching a potentially dangerous state.
B737 flight crew reported they got the stick shaker shortly after takeoff when the HUD commanded a steep pitch angle; probably because it was improperly set up.