Date: 201309
Local time of day: 0601-1200
Location: ISN.Airport, ND
Flight conditions: VMC
Light: Daylight
Aircraft: Embraer Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Takeoff / Launch
ATC / advisory: CTAF ISN
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Training / Qualification; Confusion; Communication Breakdown
Second reporter function: Pilot Not Flying; First Officer
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Weight And Balance
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Became Reoriented
Contributing factors: Environment - Non Weather Related; Company Policy; Aircraft; Procedure
Primary problem: Ambiguous

Narrative: Preflight in ISN manual weight and balance we entered all information and called Dispatch. Based on current field conditions we were given numbers for a flaps 9 takeoff Runway 29 or a flaps 18 takeoff Runway 11. We choose Runway 29 because the winds slightly favored that runway and flaps 9 is the more standard procedure. Taking the runway I decided to run the engines up with the brakes held because of the relatively short runway length. During the takeoff roll it seemed we were using a lot of runway and in my best estimate as flying pilot we got airborne with 1;000 FT of runway remaining. This seemed abnormal to both me and the First Officer. After the flight we counted the passengers and found that 44 of the 49 passengers were men and in my estimation we had 45 passengers over 200 LBS several of them closer to 300 than 200. In summary I believe we were significantly heavier than we thought we were due to underestimation of passengers' weight. I feel this may be an everyday occurrence in ISN. I have no way of verifying my hunch that we had an unsafe extended takeoff roll as I couldn't find an accelerate stop chart in our manuals. Not knowing how much passengers weighed; not knowing if flaps 18 was available for Runway 29 as we have no more charts. [We are] relying on Dispatch to run numbers with no ability to manually verify; generally not as much information available to us as before introduction of new weight and balance procedures. [It is] not as easy to make an informed decision on safest runway choice [and] flap 9/18 choice in this case. Based on the higher MGTW for Runway 11; I should have taken Runway 11 with the 5 KT tailwinds; used a more conservative passenger weight estimate in ISN or weigh each passenger manually. List available flap configurations for to each runway in a bulletin or give me at least one general takeoff distance chart to keep in my manual.


Second narrative: We boarded the aircraft noting that our flight would be full; or nearly so. From the release it seemed that we would possibly be very close to being weight restricted as our maximum takeoff weight for both runways seemed quite close to our own planned takeoff weight. We loaded up 49 passengers and approximately 30 bags; and called Dispatch to get our numbers for departure.While rolling down the runway I was somewhat glued to the 'runway length remaining' signs. I watched 6; 5; 4; and 3; go by and thought 'wow' we are using a lot of runway. I really didn't think much of it because it is a short runway and knew that we'd use a lot of it. As the nose was lifting off I watched the 1;000 FT remaining sign go from my center of vision through to the corner of my eye.There were several threats on this flight including the crew's unfamiliarity with procedures at this airport and the fact that it is uncontrolled. Neither of us had ever been to this airport. Another threat could be the fact that Dispatch put the information into [the dispatch computer program] and relayed that information to us through the telephone. Here is something that I find interesting about our situation; and something I believe could have disastrous effects on departures such as ours. When departing out of a non-[programmed] airport we rely on our dispatchers to program data and relay that information to us. On a normal flight the crew will take the information from the flight attendant and station personnel and input that data directly into ACARS. The information passes directly from the source into the computer through the flight crew. However on a non-ACARS flight like our flight this morning; that information went from the Flight Attendant and station crew; to the Captain; in a phone to a Dispatcher; into a computer; back to the Dispatcher who read it to the Captain; who wrote it on the paper. There were a lot of opportunities to have incorrect information entered in the chain of communication. (This by the way; I believe is a HUGE threat). I have to wonder today if we could have possibly had incorrect takeoff information because of a lapse in communication.I think that it's important to be more aware of what is going on during the planning process. During the few minutes prior to push it's extremely busy; especially operating a non-ACARS aircraft. It's very easy to rush though things which make it easier to miss important and relevant information to our flight.  For instance had we noticed on the ground how close MGTOW was to GTOW would we have questioned Dispatch about it?  Our V speeds seemed quite high; and the fact that they weren't split might have been something to consider. In our training were told that our automated weight and balance calculation system is a great system and that it's OK to trust that information. That may be true; but I'm not sure that I trust the way we input the information into the system. I hope the company is able to look into this flight.


Synopsis: A flight crew lifted off ISN Runway 29 with less than 1;000 FT remaining and discovered after the fact that passenger and baggage weight was heavier than calculated and other flap/runway options should have been considered.