A B737-800 first officer noticed the pdf speed tape in the low speed range and asked for flaps 25 in...

Narrative:

Flight on approach to runway; I was configuring for landing; at that time I noticed something different when I asked for gear down; flaps 15 on the airspeed indicator. The zipper changed to proper indications then reappeared therefore I was flying in the zipper approximately 170 to 175 knots; I did not want to interrupt the captain because he was looking for traffic that was close to us. After the traffic was insight I had to slow the aircraft; so I asked for flaps 25 and I was going to tell the captain about the airspeed tape and at the same time we got the speed low warning; but the airspeed was not low.captain told me to go around; this was not a normal go around. The flaps indicated they were at 8 degrees; but the flap handle was at 25 degrees and we also had a leading edge warning indication. I advanced the throttles and asked for gear up; but I did not push the toga switches because I did not want to over speed the flaps. I set speed to 180 knots for the auto throttles and used vertical speed mode set to 1;000 FPM. I knew if I pushed the toga switches that would have created an additional problem. Captain advised the tower we were going around; they said fly runway heading and climb to 4;000 feet and call departure.captain called ATC; [advised them of the situation] and asked for holding to work on the problem. The captain and I looked at the fuel load and realized that we did not have sufficient fuel to hold; work on the problem; and fly to an alternate runway; therefore we both decided to go to our alternate which had a long runway and work on the problem in route. The captain asked for radar vectors to our alternate airport. ATC advised fly heading 360 and climb to 10;000 feet. Airspeed was 180 knots and vertical speed mode was 1;000 FPM; at this time I took over ATC and flew the plane while the captain did the QRH and all check lists. He notified the flight attendants; the passengers; and the company. After all items were completed the captain took over the ATC and approach and landing was completed in our alternate.

Original NASA ASRS Text

Title: A B737-800 First Officer noticed the PDF speed tape in the low speed range and asked for Flaps 25 in preparation for landing. When the SPEED LOW warning alerted as he slowed; the crew executed a go-around; found the flaps at 8 and diverted their alternate airport with its long runway.

Narrative: Flight on approach to runway; I was configuring for landing; at that time I noticed something different when I asked for gear down; flaps 15 on the airspeed indicator. The zipper changed to proper indications then reappeared therefore I was flying in the zipper approximately 170 to 175 knots; I did not want to interrupt the Captain because he was looking for traffic that was close to us. After the traffic was insight I had to slow the aircraft; so I asked for flaps 25 and I was going to tell the Captain about the airspeed tape and at the same time we got the speed low warning; but the airspeed was not low.Captain told me to go around; this was not a normal go around. The flaps indicated they were at 8 degrees; but the flap handle was at 25 degrees and we also had a leading edge warning indication. I advanced the throttles and asked for gear up; but I did not push the TOGA switches because I did not want to over speed the flaps. I set speed to 180 knots for the auto throttles and used vertical speed mode set to 1;000 FPM. I knew if I pushed the TOGA switches that would have created an additional problem. Captain advised the Tower we were going around; they said fly runway heading and climb to 4;000 feet and call Departure.Captain called ATC; [advised them of the situation] and asked for holding to work on the problem. The Captain and I looked at the fuel load and realized that we did not have sufficient fuel to hold; work on the problem; and fly to an alternate runway; therefore we both decided to go to our alternate which had a long runway and work on the problem in route. The Captain asked for radar vectors to our alternate airport. ATC advised fly heading 360 and climb to 10;000 feet. Airspeed was 180 knots and vertical speed mode was 1;000 FPM; at this time I took over ATC and flew the plane while the Captain did the QRH and all check lists. He notified the flight attendants; the passengers; and the company. After all items were completed the Captain took over the ATC and approach and landing was completed in our alternate.

Data retrieved from NASA's ASRS site 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.

Attributes
ACN	1398157
Time
Date	201610
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Aircraft 1
Make Model Name	B737-800
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Route In Use	Visual Approach
Flight Plan	IFR
Component
Aircraft Component	Wing Trailing Edge
Person 1
Function	First Officer Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy Deviation - Speed All Types Inflight Event / Encounter Fuel Issue

A B737-800 first officer noticed the pdf speed tape in the low speed range and asked for flaps 25 in preparation for landing. When the speed low warning alerted as he slowed; the crew executed a go-around; found the flaps at 8 and diverted their alternate airport with its long runway.