Narrative:

As we departed ont on runway 26R on the pomona 7 departure; I was the pilot monitoring (pm) and the first officer was the PF. We did a normal departure in clear VMC. As we started the right turn from our 256 degree heading to join the pom 114 degree radial we were within 2-3 mi of the pom VOR. The PF selected the navigation mode and engaged the LNAV. The autoplt was engaged. At this time we were probably at about 4000-5000 ft in the climb at an IAS of 240-250 KTS. Our clearance was to climb to 14000 ft with the at or below 7000 ft restr over the pom VOR. The autoplt went into the 'altitude acquired' mode within several seconds of the autoplt engagement. It was apparent that our aircraft would complete the turn; reach 7000 ft and cross the pom at about the same instant. When the autoplt went into 'altitude acquire;' the airspeed began to gradually climb but we were still several KTS below 250 KTS. I wasn't sure if we would cross the pom VOR and be able to continue the climb at or below 250 KTS or if we would slip above 250 KTS just before we crossed that point. Not being the PF; I didn't know for sure what the plan was; but I was watching it and trying to anticipate what was going to happen. We crossed the VOR at about 253 KTS but before the climb started and the airspeed begin to bleed back off; we had reached a peak speed of 258 KTS. This period above 250 KTS lasted for a period of about 5-10 seconds. I made an 'airspeed' callout the second it went over 250 KTS as I was watching it very closely. The PF corrected immediately by simultaneously accelerating the climb rate and reducing the thrust. The correction was immediate but it still took about 5-10 seconds for the airspeed to drop below 250 KTS. The departure continued without further incident. Once above 10000 ft we ran the climb checklist then discussed the event. The FAA inspector on the jump seat said he thought there was a problem with the departure procedure design itself since he said he had observed the exact same thing happen the previous week on another company flight. On that flight; he said that the captain was the PF but the results were almost identical. He said he felt like too many things were happening at the same point (a turn; an intercept; a leveloff; a fix crossing with an immediate climb to follow). He stated that he planned to report the problem to the ATC route specialist in that area to see if they might be able to come up with a simpler departure procedure and asked us to report it to the company to see if they could get involved. On a personal level; I feel that we could have prevented it all by simply briefing that concern before we departed. There are a number of departures around the system that have a similar set of circumstances. By simply briefing it before flight we could adjust our initial climb rate (after the first 1000 ft) to approximately 1000-1500 FPM from 3000-7000 ft by simply pulling the thrust back to hold that rate of climb at 240 KTS; would have solved the problem. We would have reached 7000 ft after the pom VOR and would have never had to level off even momentarily. At that rate of climb; the 'altitude acquire' will not engage nearly as early and would thus prevent the ensuing acceleration in speed. That also would reduce a lot of unnecessary TCAS alerts with traffic in level flight just above. I feel that it would be easier for us to 'fix' the problem; rather than for ATC to 'fix' it. Just briefing it before flight would have assured that the PF and the pm (regardless of which seat did which role) were both on the same page before it all took place and that there was a game plan in place to prevent the occurrence. Callback conversation with reporter revealed the following information: reporter stated that his air carrier does not use autothrottles and that the aircraft was in vertical speed during the climb. Because of the aircraft's high climb rate that day; the autopilot transitioned to altitude acq at between 4000 ft and 5000 ft. At the time the overspeed occurred he believes the aircraft had not yet transitioned to altitude hold but it would have been the flying pilot's job to pull power in order to control speed at 250 KTS or less. The crew was feeling overloaded atthat point because the aircraft was 1-2 miles prior to pom; the reporter was looking for traffic and the first officer was heads down trying to program the LNAV after pom.

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Original NASA ASRS Text

Title: A B737-300'S FMS ON THE ONT POMONA 7 IN THE ALT ACQ MODE AS IT REACHED 7;000' PRIOR TO POM. THE ACFT OVERSPED TO 258 KTS DURING TRANSITION TO ALT HOLD.

Narrative: AS WE DEPARTED ONT ON RWY 26R ON THE POMONA 7 DEP; I WAS THE PLT MONITORING (PM) AND THE FO WAS THE PF. WE DID A NORMAL DEP IN CLR VMC. AS WE STARTED THE R TURN FROM OUR 256 DEG HDG TO JOIN THE POM 114 DEG RADIAL WE WERE WITHIN 2-3 MI OF THE POM VOR. THE PF SELECTED THE NAV MODE AND ENGAGED THE LNAV. THE AUTOPLT WAS ENGAGED. AT THIS TIME WE WERE PROBABLY AT ABOUT 4000-5000 FT IN THE CLB AT AN IAS OF 240-250 KTS. OUR CLRNC WAS TO CLB TO 14000 FT WITH THE AT OR BELOW 7000 FT RESTR OVER THE POM VOR. THE AUTOPLT WENT INTO THE 'ALT ACQUIRED' MODE WITHIN SEVERAL SECONDS OF THE AUTOPLT ENGAGEMENT. IT WAS APPARENT THAT OUR ACFT WOULD COMPLETE THE TURN; REACH 7000 FT AND CROSS THE POM AT ABOUT THE SAME INSTANT. WHEN THE AUTOPLT WENT INTO 'ALT ACQUIRE;' THE AIRSPD BEGAN TO GRADUALLY CLB BUT WE WERE STILL SEVERAL KTS BELOW 250 KTS. I WASN'T SURE IF WE WOULD CROSS THE POM VOR AND BE ABLE TO CONTINUE THE CLB AT OR BELOW 250 KTS OR IF WE WOULD SLIP ABOVE 250 KTS JUST BEFORE WE CROSSED THAT POINT. NOT BEING THE PF; I DIDN'T KNOW FOR SURE WHAT THE PLAN WAS; BUT I WAS WATCHING IT AND TRYING TO ANTICIPATE WHAT WAS GOING TO HAPPEN. WE CROSSED THE VOR AT ABOUT 253 KTS BUT BEFORE THE CLB STARTED AND THE AIRSPD BEGIN TO BLEED BACK OFF; WE HAD REACHED A PEAK SPD OF 258 KTS. THIS PERIOD ABOVE 250 KTS LASTED FOR A PERIOD OF ABOUT 5-10 SECONDS. I MADE AN 'AIRSPD' CALLOUT THE SECOND IT WENT OVER 250 KTS AS I WAS WATCHING IT VERY CLOSELY. THE PF CORRECTED IMMEDIATELY BY SIMULTANEOUSLY ACCELERATING THE CLB RATE AND REDUCING THE THRUST. THE CORRECTION WAS IMMEDIATE BUT IT STILL TOOK ABOUT 5-10 SECONDS FOR THE AIRSPD TO DROP BELOW 250 KTS. THE DEP CONTINUED WITHOUT FURTHER INCIDENT. ONCE ABOVE 10000 FT WE RAN THE CLB CHKLIST THEN DISCUSSED THE EVENT. THE FAA INSPECTOR ON THE JUMP SEAT SAID HE THOUGHT THERE WAS A PROB WITH THE DEP PROC DESIGN ITSELF SINCE HE SAID HE HAD OBSERVED THE EXACT SAME THING HAPPEN THE PREVIOUS WK ON ANOTHER COMPANY FLT. ON THAT FLT; HE SAID THAT THE CAPT WAS THE PF BUT THE RESULTS WERE ALMOST IDENTICAL. HE SAID HE FELT LIKE TOO MANY THINGS WERE HAPPENING AT THE SAME POINT (A TURN; AN INTERCEPT; A LEVELOFF; A FIX XING WITH AN IMMEDIATE CLB TO FOLLOW). HE STATED THAT HE PLANNED TO RPT THE PROB TO THE ATC RTE SPECIALIST IN THAT AREA TO SEE IF THEY MIGHT BE ABLE TO COME UP WITH A SIMPLER DEP PROC AND ASKED US TO RPT IT TO THE COMPANY TO SEE IF THEY COULD GET INVOLVED. ON A PERSONAL LEVEL; I FEEL THAT WE COULD HAVE PREVENTED IT ALL BY SIMPLY BRIEFING THAT CONCERN BEFORE WE DEPARTED. THERE ARE A NUMBER OF DEPS AROUND THE SYS THAT HAVE A SIMILAR SET OF CIRCUMSTANCES. BY SIMPLY BRIEFING IT BEFORE FLT WE COULD ADJUST OUR INITIAL CLB RATE (AFTER THE FIRST 1000 FT) TO APPROX 1000-1500 FPM FROM 3000-7000 FT BY SIMPLY PULLING THE THRUST BACK TO HOLD THAT RATE OF CLB AT 240 KTS; WOULD HAVE SOLVED THE PROB. WE WOULD HAVE REACHED 7000 FT AFTER THE POM VOR AND WOULD HAVE NEVER HAD TO LEVEL OFF EVEN MOMENTARILY. AT THAT RATE OF CLB; THE 'ALT ACQUIRE' WILL NOT ENGAGE NEARLY AS EARLY AND WOULD THUS PREVENT THE ENSUING ACCELERATION IN SPD. THAT ALSO WOULD REDUCE A LOT OF UNNECESSARY TCAS ALERTS WITH TFC IN LEVEL FLT JUST ABOVE. I FEEL THAT IT WOULD BE EASIER FOR US TO 'FIX' THE PROB; RATHER THAN FOR ATC TO 'FIX' IT. JUST BRIEFING IT BEFORE FLT WOULD HAVE ASSURED THAT THE PF AND THE PM (REGARDLESS OF WHICH SEAT DID WHICH ROLE) WERE BOTH ON THE SAME PAGE BEFORE IT ALL TOOK PLACE AND THAT THERE WAS A GAME PLAN IN PLACE TO PREVENT THE OCCURRENCE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED THAT HIS ACR DOES NOT USE AUTOTHROTTLES AND THAT THE ACFT WAS IN VERTICAL SPD DURING THE CLB. BECAUSE OF THE ACFT'S HIGH CLB RATE THAT DAY; THE AUTOPILOT TRANSITIONED TO ALT ACQ AT BETWEEN 4000 FT AND 5000 FT. AT THE TIME THE OVERSPEED OCCURRED HE BELIEVES THE ACFT HAD NOT YET TRANSITIONED TO ALT HOLD BUT IT WOULD HAVE BEEN THE FLYING PILOT'S JOB TO PULL POWER IN ORDER TO CONTROL SPEED AT 250 KTS OR LESS. THE CREW WAS FEELING OVERLOADED ATTHAT POINT BECAUSE THE ACFT WAS 1-2 MILES PRIOR TO POM; THE REPORTER WAS LOOKING FOR TFC AND THE FO WAS HEADS DOWN TRYING TO PROGRAM THE LNAV AFTER POM.

Data retrieved from NASA's ASRS site as of January 2009 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.