MD-80 Series (DC-9-80) Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Distraction; Situational Awareness
Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Became Reoriented
Company Policy; Human Factors
The FO was the PF and I was the PM. Flying out of LAS on the Shead 9 departure ATC instructed us to level off at 11000 feet instead the usual FL190 for this departure. Our new standard operating procedure is to use Cost Index 70 in the FMS which will climb the plane at 335 KIAS once above 10000 until transitioning to Mach speeds at around FL250 or so. The plane was on autopilot with the FMS in VNAV. After passing 10000 feet the airplane pitched down to accelerate to 335 KIAS. Once leveling at 11000 the FMS retarded the autothrottles from climb power to a power setting that would maintain 335 KIAS. Our VMO is 340 KIAS. So the barberpole and the airspeed indicator needle are almost on top of each other while in this now 'normal' mode. Subsequently ATC cleared us to FL190. I set the altitude in the altitude pre-selector and the PF engaged the FMS in VNAV climb. The autothrottles advanced and the aircraft started to pitch up; however; the autothrottles added the power quicker than the autopilot did the pitching up. I was not 'glued' on the airspeed indicator since the airplane was in the proper automation mode and I was busy attending to other duties as well (climb-check at 10000; entering proposed times in the flight-plan log; adjusting cabin temperatures; verifying correct modes on the FMA; changing the frequencies on Com 2 etc.) I was alerted by the overspeed clacker that we must have accelerated to our VMO. I looked at the airspeed indicator and saw both needles on top of each other. The PF promptly adjusted the climb speed on the DFGS to 320 KIAS in order to maintain a more acceptable buffer to our VMO in deviation from our SOP guidance. I made a logbook entry upon arrival [and] no discrepancies were found.Our new procedure puts our climb speed with 335 KIAS awfully close to our VMO on every flight from approx. 10000 MSL until the mid-20s flight levels. That is a long time and gives the airplane ample opportunities to 'accidentally' accelerate to our VMO be it due to sluggish autopilots; binary autothrottles that know only full forward or aft; sudden turbulence; windshear; wake turbulence; gusts; inversion layers; embedded convective activity etc. etc. Ever since that procedure was implemented 'every' single FO that I have flown with since modifies the FMS to climb out at a slower speed than commanded. And while I agree that this is a good idea it also violates our standard operating procedure. Why are we implementing a procedure that virtually no pilot feels comfortable following ever on any single flight? And if you do follow it then you better stay glued to the airspeed indicator in order to avoid overspeeds while neglecting other duties and a proper scan of all other flight instruments.It is my recommendation to implement [the new procedure] for cruise only and use a more conservative Index for our climb profile. I will from now on override the FMS on every single climbout in order to maintain a safe buffer between our actual airspeed and VMO and 335 KIAS is not the number I shall use as it is too close to our overspeed limit considering the capabilities of our equipment and the fluid dynamics of the ever changing atmospheric conditions. Given the choice of following a newly implemented procedure or maintaining a safe airspeed I believe it is in the best interest of safety to do the latter.
MD-80 Captain reported an overspeed in climb that he felt was related to a recent change in procedure that calls for a high speed climbout.