Parallel approachs. Visual separation difficult to maintain until touchdown.

Attributes
ACN	305576
Time
Date	199505
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : sfo
State Reference	CA
Altitude	msl bound lower : 100 msl bound upper : 1000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : sfo tower : sfo
Operator	common carrier : air carrier
Make Model Name	DC-10 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	descent : approach landing other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : flight engineer pilot : instrument pilot : commercial
Experience	flight time last 90 days : 210 flight time total : 16000 flight time type : 800
ASRS Report	305576
Person 2
Affiliation	company : air carrier
Function	flight crew : second officer
Qualification	pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 240 flight time total : 9000 flight time type : 5000
ASRS Report	305833
Events
Anomaly	other anomaly other other anomaly other
Independent Detector	other flight crewa
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other

Narrative:

Accepted a visual approach to runway 28R sfo at about 8 mi. Approach pointed out traffic on runway 28L and gave us a reduction in speed to 170 KTS. We slowed to minimum approach speed in attempt to remain behind and visual on traffic on runway 28L and it appeared we would be able to do that but at about 100 ft AGL we pulled along side the traffic on runway 28L and while I was able to maintain visual on traffic (from left seat, first officer flying the aircraft) at the last min on final we were not able to remain behind the aircraft on runway 28L. It should be noted that the other aircraft was a commuter type with a higher profile glide path and landing longer than we were, this helped us maintain visual longer than we could have normally. It is very difficult to maintain visual separation and judge closure rates on this approach, particularly with different aircraft types and different profiles to the runways. Under these circumstances I will be reluctant to accept a visual approach again. Considering the different speeds we should have had more separation when cleared for the approach and I should have recognized that earlier.

Original NASA ASRS Text

Title: PARALLEL APCHS. VISUAL SEPARATION DIFFICULT TO MAINTAIN UNTIL TOUCHDOWN.

Narrative: ACCEPTED A VISUAL APCH TO RWY 28R SFO AT ABOUT 8 MI. APCH POINTED OUT TFC ON RWY 28L AND GAVE US A REDUCTION IN SPD TO 170 KTS. WE SLOWED TO MINIMUM APCH SPD IN ATTEMPT TO REMAIN BEHIND AND VISUAL ON TFC ON RWY 28L AND IT APPEARED WE WOULD BE ABLE TO DO THAT BUT AT ABOUT 100 FT AGL WE PULLED ALONG SIDE THE TFC ON RWY 28L AND WHILE I WAS ABLE TO MAINTAIN VISUAL ON TFC (FROM L SEAT, FO FLYING THE ACFT) AT THE LAST MIN ON FINAL WE WERE NOT ABLE TO REMAIN BEHIND THE ACFT ON RWY 28L. IT SHOULD BE NOTED THAT THE OTHER ACFT WAS A COMMUTER TYPE WITH A HIGHER PROFILE GLIDE PATH AND LNDG LONGER THAN WE WERE, THIS HELPED US MAINTAIN VISUAL LONGER THAN WE COULD HAVE NORMALLY. IT IS VERY DIFFICULT TO MAINTAIN VISUAL SEPARATION AND JUDGE CLOSURE RATES ON THIS APCH, PARTICULARLY WITH DIFFERENT ACFT TYPES AND DIFFERENT PROFILES TO THE RWYS. UNDER THESE CIRCUMSTANCES I WILL BE RELUCTANT TO ACCEPT A VISUAL APCH AGAIN. CONSIDERING THE DIFFERENT SPDS WE SHOULD HAVE HAD MORE SEPARATION WHEN CLRED FOR THE APCH AND I SHOULD HAVE RECOGNIZED THAT EARLIER.

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