B777 flight crew describes the circumstances leading up to a go-around during vectors for an ILS to ...

Attributes
ACN	1100174
Time
Date	201307
Local Time Of Day	0001-0600
Place
Locale Reference	IAD.Airport
State Reference	DC
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	B777 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Plan	IFR
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 265 Flight Crew Total 19385 Flight Crew Type 4993
Person 2
Function	Pilot Not Flying First Officer
Experience	Flight Crew Last 90 Days 160 Flight Crew Total 16000 Flight Crew Type 3500
Events
Anomaly	ATC Issue All Types Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Deviation - Speed All Types

Narrative:

We were vectored to intercept 19L localizer at 4;000 feet outside of izumi at 210 knots. Prior to intercept we were again vectored to intercept 19L localizer about 7-8 NM outside of domsi at 180 knots. Just before intercept we were told to look for traffic at 10 o'clock and the runway and report either or both. We saw the runway and called it and I thought we were given clearance to land so I armed the approach mode of the autopilot system. We spotted the traffic at our 12 o'clock and about 2-3 NM ahead at 2;100 feet. He was being vectored in front of us for the same runway. We told the ATC we were too close and he replied he only needed 3/10 of a mile separation to make it legal. The autopilot system then captured the glideslope and we started out of 4;000 feet and since the three of us could not agree if we were given the approach clearance we called and asked and we were told to maintain 4;000 feet. I clicked off the autopilot after descending 300-400 feet and got back to 4;000 feet. In the process of correcting my mistake; the airspeed dropped into the low airspeed (yellow bracket) momentarily as I pushed the throttles up. Then ATC gave us a turn to 160 and then back to 220 to intercept the localizer but by this time we were still at 4;000 feet and only 2.5 NM from the outer marker so we called for a go-around. ATC took us out to the east and brought us back into the localizer about 7 NM out for an uneventful approach.

Original NASA ASRS Text

Title: B777 flight crew describes the circumstances leading up to a go-around during vectors for an ILS to Runway 19L at IAD. A descent is initiated and airspeed gets low due to minimal spacing with the traffic ahead.

Narrative: We were vectored to intercept 19L localizer at 4;000 feet outside of IZUMI at 210 knots. Prior to intercept we were again vectored to intercept 19L localizer about 7-8 NM outside of DOMSI at 180 knots. Just before intercept we were told to look for traffic at 10 o'clock and the runway and report either or both. We saw the runway and called it and I thought we were given clearance to land so I armed the approach mode of the autopilot system. We spotted the traffic at our 12 o'clock and about 2-3 NM ahead at 2;100 feet. He was being vectored in front of us for the same runway. We told the ATC we were too close and he replied he only needed 3/10 of a mile separation to make it legal. The autopilot system then captured the glideslope and we started out of 4;000 feet and since the three of us could not agree if we were given the approach clearance we called and asked and we were told to maintain 4;000 feet. I clicked off the autopilot after descending 300-400 feet and got back to 4;000 feet. In the process of correcting my mistake; the airspeed dropped into the low airspeed (yellow bracket) momentarily as I pushed the throttles up. Then ATC gave us a turn to 160 and then back to 220 to intercept the localizer but by this time we were still at 4;000 feet and only 2.5 NM from the outer marker so we called for a go-around. ATC took us out to the east and brought us back into the localizer about 7 NM out for an uneventful approach.

Data retrieved from NASA's ASRS site as of July 2013 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.

B777 flight crew describes the circumstances leading up to a go-around during vectors for an ILS to runway 19L at iad. A descent is initiated and airspeed gets low due to minimal spacing with the traffic ahead.