<< >> NASA ASRS Report 104137, February 1989

Flight crew complaint about sequence flashing white obstruction lights on power company towers 5 NM from runway 10 at pdx.

Attributes
ACN	104137
Time
Date	198902
Day	Fri
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : pdx
State Reference	OR
Altitude	msl bound lower : 1300 msl bound upper : 1300
Environment
Flight Conditions	Mixed
Light	Night
Aircraft 1
Controlling Facilities	tower : pdx tower : day
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : instrument pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 150 flight time total : 9000 flight time type : 100
ASRS Report	104137
Person 2
Affiliation	government : faa
Function	controller : local
Qualification	controller : radar
Events
Anomaly	inflight encounter other
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Airport
Air Traffic Incident	other
Situations
Airport	other physical facility

Narrative:

On localizer approach runway 10 pdx (G/south inoperative) at 600' above MDA I came out of the clouds. Immediately in front of me were flashing white lights that appeared to be sequenced flasher lead-in lights. Since I appeared to be high and close (referencing the white lights) I rechked altitude and DME and realized that the runway had to be 5 NM in front of me. About 1 NM further the runway lights became visible. Later conversation with tower indicated I had seen obstruction lights on a power line (?) crossing the columbia river. On a marginal visibility approach, with high winds, turbulence and shears, the potential to mistake those flashing white lights for sequenced approach lights is significant. I believe the obstruction lights should be red versus white and if they must flash they should flash consistently and not in an alternating or sequenced fashion. The lack of G/south on the approach was a contributing factor, but need not have been significant.

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Original NASA ASRS Text

Title: FLT CREW COMPLAINT ABOUT SEQUENCE FLASHING WHITE OBSTRUCTION LIGHTS ON POWER COMPANY TOWERS 5 NM FROM RWY 10 AT PDX.

Narrative: ON LOC APCH RWY 10 PDX (G/S INOP) AT 600' ABOVE MDA I CAME OUT OF THE CLOUDS. IMMEDIATELY IN FRONT OF ME WERE FLASHING WHITE LIGHTS THAT APPEARED TO BE SEQUENCED FLASHER LEAD-IN LIGHTS. SINCE I APPEARED TO BE HIGH AND CLOSE (REFERENCING THE WHITE LIGHTS) I RECHKED ALT AND DME AND REALIZED THAT THE RWY HAD TO BE 5 NM IN FRONT OF ME. ABOUT 1 NM FURTHER THE RWY LIGHTS BECAME VISIBLE. LATER CONVERSATION WITH TWR INDICATED I HAD SEEN OBSTRUCTION LIGHTS ON A POWER LINE (?) XING THE COLUMBIA RIVER. ON A MARGINAL VISIBILITY APCH, WITH HIGH WINDS, TURB AND SHEARS, THE POTENTIAL TO MISTAKE THOSE FLASHING WHITE LIGHTS FOR SEQUENCED APCH LIGHTS IS SIGNIFICANT. I BELIEVE THE OBSTRUCTION LIGHTS SHOULD BE RED VERSUS WHITE AND IF THEY MUST FLASH THEY SHOULD FLASH CONSISTENTLY AND NOT IN AN ALTERNATING OR SEQUENCED FASHION. THE LACK OF G/S ON THE APCH WAS A CONTRIBUTING FACTOR, BUT NEED NOT HAVE BEEN SIGNIFICANT.

Data retrieved from NASA's ASRS site as of August 2007 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.