Date: 201204
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: Q400
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
ATC / advisory: Ground ZZZ
Second aircraft: B737 Undifferentiated or Other Model
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Fatigue; Other / Unknown; Time Pressure; Communication Breakdown
Anomaly: Conflict Ground Conflict; Critical
Detector: Person Flight Crew
When detected: Taxi
Result: Flight Crew Took Evasive Action
Contributing factors: Human Factors; Company Policy
Primary problem: Human Factors

Narrative: While northbound on taxiway S; I was cleared to Runway XXL via S; D; D10; E. The north half of ZZZ seemed nearly deserted of taxiing aircraft. On S; I could see no one ahead of me or approaching from behind on D or E. As I turned onto D from S my path along D and E looked like it would be clear all the way to XXL. Anything I saw looked far away from me. The portion of E that I could see ahead of the Q400 left wing tip remained clear as I taxied east on D. I turned onto D10 and as the aircraft rotated so that I could see what was behind me past the wing tip on E I perceived orange movement and slammed on the brakes as a Boeing 737 came into view close and moving rapidly left to right on E. I came to a stop beyond the dashed lines separating D from E and could see that the risk of collision had passed (because I had stopped in time) and that the B737 wing tip would clear the nose of the Q400 with more than room to spare. After I stopped the aircraft; the next sound was of the First Officer yelling 'Holy crap!' A few seconds after B737 passed I continued my taxi onto E and the next sound was of apologetic transmissions from ZZZ Ground Control for what had just happened and I recall hearing 'Air Carrier X; that was NOT your fault.' There were no transmissions at any time either to or from the B737 crew on ground frequency immediately before or at any time after the incident before we switched to Tower frequency. At the end of this event I believed that the Controller; myself; and the First Officer were definitely aware. I do not know if the B737 crew was aware. Despite my slamming on the brakes my stop was not violent as the brakes were cold and take a lot of force to stop and I do not believe that the cabin crew or passengers were aware. Sometime after completion of the flight I confirmed that the flight attendants were not aware.The simplistic cause of this event is two aircraft coming within 2-3 seconds of trying to occupy the same space at the same time while taxiing at ZZZ. The more helpful cause of this event will need a larger perspective than the one I can provide. One can expect that many contributors to the cause of the event are fleeting bits of information that may not be captured or have to be recreated from available information. One can also expect that the information that is captured will be filtered through individual bias in the process of being captured. I provided my own description of the event above and surely contributed my own bias. To more fully understand the cause means getting information and bias from the First Officer I flew with; the First Officer and Captain of the B737 flight; the Ground Controller involved; any ATC personnel in close proximity to the Ground Controller involved; records of cockpit conversations (now too late); records of communications at ZZZ before and immediately after the event; and any ground radar tracks and available imagery. Of course; any bias should be filtered out to the extent possible. What I can provide is my perspective on how the event that did not happen was avoided. The event I'm referring to is the two aircraft coming together in about a 38 knot collision perhaps totaling two aircraft at a cost of $80 million or so combined; staining the reputation of ZZZ Ground Control; staining the reputation of [the other company] and their taxi procedures; not doing any good for my reputation; and perhaps killing myself and whoever else happened to be in the way of the part of the B737 that penetrated the Q400.I can identify two factors that contributed to the more costly event not happening. The first factor is that I was adequately rested. I was not well rested; but I was adequately rested. I got about 6 hours and 45 minutes of sleep the night before. I consider well rested to be 8 or more hours of sleep in the previous 24 hours. This was a two day trip for me and I was by far the most rested person of the crew. I have had the opportunity to use excess vacation anduse the provisions of my union contract to give myself more days off and more rest and better trips over the past 6 months. Better rest provides for a healthier mental outlook; improved alertness; and better self-discipline in the cockpit. It all paid off in a big way on the taxiway at ZZZ. Luck contributed to the first factor also-meaning that I was adequately rested. We were lucky that this event happened after the union took over trip building in early 2011. We were lucky for the incremental improvements that the union was able to make in trips that contribute to incrementally more rested pilots. We were lucky that this did not happen in the fall of 2010 when perhaps the least responsible trips ever [were produced] in the history of Air Carrier X and when I was perhaps the most fatigued I have been since doing field training in a light infantry unit many years ago. We were lucky this did not happen in the summer of 2010 when 70 Air Carrier X pilots per month were removing themselves from trips as too fatigued to fly. By my estimate; only 1 in 10 Air Carrier X pilots that are too fatigued to fly removes themselves from work making the true figure of pilots too fatigued to fly safely and avoid a collision with B737 perhaps close to 700 occasions per month in summer 2010. We were lucky that I have no plans for working at Air Carrier Y. The word is out among Air Carrier X pilots that the Air Carrier X Chief Pilot is turning sick call information from Air Carrier X over to Air Carrier Y HR; making working sick and unfit to fly a (perceived) necessity for those Air Carrier X pilots planning to move on to Air Carrier Y. We are lucky we have a union at Air Carrier X. Senior VP of Air Carrier X Air Operations said directly to me; 'Air Carrier X has NO responsibility to schedule safely. That is YOUR responsibility. It is your union's job to negotiate it.' We are also lucky that we were not flying the schedules proposed by Air Carrier X management recently for the new proposed ZZZ1 base that will have nearly all Air Carrier X ZZZ1 based pilots repeatedly on almost every trip swapping between getting up at 3 or 4 a.m. and working until midnight every few days; every week; and every month. Non-stop circadian swaps for eternity; Non-stop high risk pilots until; and if; the union is able to intercede. The second factor contributing to the costly event not happening is that I was stubborn. I was stubbornly taxiing with an abundance of caution when many might argue there were no threats to be avoided and I was stubbornly looking for threats while I taxied. All (perhaps 95% that is) of the traffic and congestion at ZZZ immediately preceding the event were at the south side of the airport. Once I hit taxi way S; the traffic and threats were behind me and I had a clear shot all the way to XXL. Or; at least I thought all the ground threats were behind me on the south side. As mentioned earlier; the north side was nearly deserted. By taxi with caution; I estimate I was going about 18 knots on the straight ways of S and D and about 10 knots or slightly faster on the roomy (for a Q400) turns such as S to D and D/D10 to E. I had my HUD down; but am not aware of ever looking inside to check my speed. All my attention during the taxi other than checklists was outside the cockpit. So; when B737 appeared on E; I was probably going a little slower than my management considers safe and I was looking out the window for threats and I was pretty quick on the brakes. I am aware of 9 pilots at my base being called in by management and threatened with termination for going slow over the recent several weeks and months. This represents more than 10% of the captains at my base recently threatened with termination. When you subtract Check Airmen who are not at risk and subtract the Air Carrier X speed demons; the risk to a cautious pilot may be closer to 20%. To both my great relief and great surprise I was not on the list of those found offensive to management.I am thankful. I believe that the purpose of the threats is no so much to fire the 10% threatened but to put a chill on the other 90% that might choose to operate a little safer at the price of a little speed. My speed coming around the corner when I saw B737 may have been slow enough to generate a frown from management had I been observed in other than the context of this report. I never in a million years expected to see B737 or anyone on E coming from the left. I perceived that I was operating in a very low threat environment once I cleared the south half of ZZZ airport. I perceived that I was being a little overly cautious on the ground at ZZZ that day.I am now going to move into the area of conjecture in an attempt to help with the identification of possible causes. Conjecture means what might be the case based on my experience and might just as easily be found to be not the case. My first conjecture is that I am not aware of any errors on the part of the B737 crew; the ground controllers or myself. This B737 crew was operating within the norms of taxi speed for every other crew. My next conjecture is to ask whether the B737 crew ever saw me during the event. If they did not see me I don't really have any more to offer along that line of thought. If the B737 crew did see me; my conjectures can go in several directions. One direction I can go with this is that I was seen on taxi way D before I reached D10 and dismissed as a threat to the safety of the B737 flight. Why would I be dismissed as a threat? Well; if it was an experienced B737 crew they may have known that Air Carrier X only makes right turns into the alley where Air Carrier Y and Air Carrier X park; except that this changed a few weeks ago when Air Carrier Y/Air Carrier X [relocated terminals]. Another conjecture I'll make is that B737 noticed the same thing that I did -- that there was an unusually small amount of traffic around D and E and you could 'safely' open her up and speed to the gate. Another conjecture is that is that as speed increases one looks further ahead. One looks further down the road on the interstate in Wyoming than one looks when pulling out of one's driveway in a quiet residential area. B737 may have visually cleared D10 of threats and have been looking at D9 or beyond as I was doing the D-D10-E turn. One's cone of vision directs more ahead than to the side as well. Also; this same idea may have affected me as well. I had already seen that E was 'clear' while I was on D. Although I was looking onto E as I turned; I sure as heck was not looking for a fast mover and was quite surprised-or should I say more surprised as I would have been surprised to see anyone there at any speed. So; if B737 was looking beyond the threat; I was looking almost too close to see a slightly more distant threat.There you have it. All I'm sure about is that I have no idea which of my conjectures is close to the mark -- maybe none are -- and which are far from the mark. I'd sure like to know the rest of the story.




Synopsis: A ground conflict with a fast taxiing B737--avoided by abrupt braking following late recognition of the hazard--compelled the Captain of a Q400 to submit a lengthy report addressing the commuter airline's physiologically debilitating scheduling and its deleterious effects on situational awareness and timely responses to such crises on the part of their flight crew.