Date: 201205
Local time of day: 0001-0600
Location: ZSE.ARTCC, WA
Flight conditions: IMC
Light: Dawn
Aircraft: Widebody Transport
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Cargo / Freight / Delivery
Flight phase: Cruise; Initial Approach; Final Approach
Airspace: Class A ZSE; Class B SEA
ATC / advisory: Center ZSE; Tower SEA
Aircraft component: Air/Ground Communication
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Distraction; Fatigue; Situational Awareness
Second reporter function: First Officer; Pilot Not Flying
Anomaly: Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT
Detector: Person Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented
Contributing factors: Environment - Non Weather Related; Human Factors; Procedure
Primary problem: Human Factors

Narrative: I removed my headset to stretch; yawn; etc; then the First Officer took a physiological break and I put the O2 mask on; but neglected to turn up the overhead speaker. When the First Officer returned to the cockpit he neglected to put his headset on and when I removed the O2 mask I also did not turn on my overhead speaker nor put on my headset. During a period of about 10-15 minutes neither of us had a headset on or the overhead speakers at a listening level. We received an ACARS Air-Air message that ATC wanted to talk with us. They had tried several times to reach us on the radio and finally asked a Company aircraft to message us which they did. We re-established radio comm with ATC and they did not appear concerned. We were both very tired and sleepy and had been drinking coffee in attempt to stay focused but the fatigue issue made us a bit sloppy with our attention to communication procedures. The overhead HUD projector has interfered with my use of the speaker in the past so I have got into the habit of just wearing my headset all of the time. I broke a habit pattern due to lack of sleep; but I will not do it again. Always ensure the speaker column is up when the mask is on and check it again after any crew change or when a crew member has taken a break. Always keep some column on even if wearing the headset.  A normal Flaps 35 ILS approach and landing was briefed for arrival. Weather was overcast with 10 miles visibility. I elected to use the HUD for my own training proficiency. After configuring the aircraft with the gear down and flaps at 28 deg; I disconnected the autopilot with the runways in sight on approach but we had a speed restriction of 170 knots to the FAF on 16C. I had configured early knowing that I was tired and wanted to have safe methodical and well stabilized approach. Coming down final; on one of my airspeed crosschecks the airspeed did not seem correct; but I could not identify what was wrong with it as I was just above the amber foot and the autothrottles were working efficiently; but I did have my hand on them 'in case.' The HUD projection was working well and I was established on LOC and Glide Slope and the runway clearly visible in front of me. The PM called stable at 500 FT; but failed to notice 'no green box' and shortly after we received the GPWS 'To low Flaps' warning. I knew immediately that I had failed to call for flaps 35. My evaluation of terrain; runway; and the airplane determined a call to set the flaps at 35; which we did; and I made an uneventful landing. The pitch forces and trim changes from 28-35 are minuscule thus the landing was well within acceptable parameters. I should have gone around at the GPWS call. I think my fatigue was the biggest factor and that is the fatigue of back side of the clock flying. I had plenty of rest previous nights; but just not enough prior to this flight with a  show after night. I woke up at midnight and drove to work after getting about 3 hrs rest. I should have vocalized my earlier concern to the First Officer about my concern that something didn't seem right when on final. And I should have gone around. We clearly did not have a green box on final and I always check that but did not this time for some reason. I will always check it in the future regardless. When using the HUD you must move your head a bit to see the display and the green box symbology. I did not and should have gone around. Train our pilots to recognize fatigue signs during critical phases of flight. Train our pilots ensure a 'Green Box' prior to the stable call. I should have gone around.


Second narrative: I realized that upon returning from the break; I neglected to replace my headset on my head; and that; coupled with having my cockpit speaker turned down; did not allow me to hear SEA center's request to change frequencies.On final approach into SEA; the 'too-low flaps' aural warning activated. We realized that the flaps were set at 28 degrees vs. 35 degrees and we placed the flaps into the 35 degree setting and completed the before landing check on short final and landed the aircraft. Causes and Contributing factors: Fatigue:  From prior experience and airmanship; I realized that fatigue on this flight sequence would definitely be present in some form. I was sure that this particular flight would be the most fatiguing on my schedule for the month. I therefore initiated fatigue risk management strategies beginning on the first of the month when I swapped off a day turn with a 36 hour layover into this pairing with this night turn flight. I realized and was aware that when I chose to do this swap; that I was increasing my risk exposure for mishap events.  I also realized that in this 4+ hour flight sequence; that I would be jumpseating into the night turn for the first time in many months and this also increased my risk exposure. To mitigate this exposure; I planned on three possibilities for napping opportunities: 1) during the afternoon at home prior to jumpseating 2) On the jumpseat to work; and 3) on the two hour turn at my crew base.  I chose not to drink coffee or any caffeinated beverage after 10 am to help my chances of being able to nap.  I unfortunately was not tired and was not able nap during these periods. To further mitigate this exposure to fatigue; I planned; and chose; to drink coffee at show time; and during preflight which I did do. This strategy worked fairly well and I was alert for all of the flight. I also planned on having another cup of coffee prior to descent which I did not do; as I felt an above average level of alertness throughout the flight and prior to descent. While I felt alert; I realized and was fully aware that fatigue was present within myself because of my lack of sleep in the past 24 hours. Therefore; I made a conscious effort at telling myself to increase my vigilance on the approach phase. However; this was not enough and I found myself focusing on the airspeed and glidepath during the approach; even though those parameters varied little. I did not fully complete the before landing check; and I made a stable call out at 500 FT RA and stated we were cleared to land; even though the aircraft was still configured with 28 degrees of flaps. This resulted in the aural warning. Given that these events have never happened to me in my flying career; I must attribute this event as the result of fatigue; and I fully believe that this situation would be much less likely to have occurred during a similar day flight. Other factors: Flight Discipline: On the room for improvement side; not choosing to initiate a go around is a concern as looking back on this sequence of events; and being technically unstable; requires a course of action which I did not attempt to initiate. Airmanship:  On the positive side; given all of the other factors involved; I realized that a safe and fully configured 35 degree flap landing was entirely probable given the situation of every other parameter being met with clear; calm; VMC conditions; and chose to continue the approach versus initiate and request a go around. I believe that I must have a more 'go-around' mentality versus a 'land' mentality.  Also; I must be even more vigilant to the effects of managing my fatigue risks; especially during the approach and landing phases of flight. Unfortunately; I don't know how I could be more risk averse given the situations; without calling in fatigued on nearly every night flight.


Synopsis: A Cargo flight crew described fatigue induced communication and procedural errors during flight after their inability to sleep during the previous daylight rest cycle.