cblaisd

On UA flight 1607 (an Airbus 319), RNO-SFO, this afternoon, we we did the Point Reyes-then SFO VOR-then depart SFO VOR on 140 radial for the downwind leg (This seems a common approach to set up a left-downwind that is as long as necessary for traffic conditions?). Over Moffett Field we were given our base turn and then fairly quickly a turn to final for 28L. Approach control asked our pilot if a) he had the field in sight, and b) if he had the Delta 757 in sight which was at the same time turning from a right base leg to final for 28R. Our captain replied affirmatively to both and was then cleared for the approach to 28L and the controller then told him that the Delta 757 would be landing on the parallel. As we came down the final approach course, the Delta aircraft was exactly abeam us and the speeds were the same. The Delta captain once asked Approach if the UA traffic (us) was going to speed up or slow down; the controller replied "negative; he's landing on the parallel." South of the San Mateo Bridge, per usual, we were handed off to the tower controller. Still the two aircraft were absolutely even and abeam one another, as if they were connected by an invisible rod. Just north of the San Mateo bridge, though, the Delta aircraft suddenly stopped descending and then slowly began to climb and the Delta captain came on the frequency and said "We're breaking off the approach; that guy's just too close to us." Tower then gave him a 280 heading and handed him off to departure for his go-around.

I waited for the pilots after our flight and asked them why the Delta captain had done a go-around. They simply said they guessed he was uncomfortable with how close together the aircraft were; I didn't push for any further explanation or supposition on their parts. My question of Mark Rogers (or if we have other UA pilots lurking here), then, is this: Why might the Delta pilot have been uncomfortable with the parallel landing? Does Delta have different rules for pilots for parallel approaches at SFO on the 28L/R than does UA? (And with that last line maybe this even belongs now in the UA forum )

UAPremierExec

Wake turbulence from the 757 could very well have been a factor.. plus those runways are alot closer together than most.

I've came into SFO once from LAS on an A320.. we had a 744 just behind us by about 100 feet.. we both landed @ the same time, including flare... i *wish* i had my camera with me... it was awesome.

((fyi, i'm only a student pilot))

-n

Mark Rogers

The runways at San Francisco are very tightly spaced - just 750 feet apart. These runways are far closer than the 4300' needed to conduct independent parallel instrument approaches, so in order to use both runways at the same time, visual approaches must be used. In a visual approach, one or both of the participating aircraft must maintain separation with the other aircraft on the approach. Until the San Mateo bridge, both aircraft would be flying the speed assigned by ATC, most likely 180 knots. After the bridge, each aircraft will slow to approach speed. The A319 approach speed (especially after a short flight from RNO) would have likely been quite a bit slower than the approach speed of the DL 757. If the Delta 757 had been instructed to maintain visual separation with the A319, it would be impossible to do this if the A319 passed behind, and it would be impossible to slow below approach speed, thus prompting a go-around. Alternatively, the DL crew could have just felt the aircraft were too close regardless, and initiated a go-around. Even at SFO, it's fairly rare to be exactly abeam another aircraft; usually you're staggered a few hundred feet and the trailing aircraft is responsible for ensuring visual separation.

As far as I know, DL does not have any different procedures for parallel visual approaches than anyone else. If they did, they likely wouldn't have accepted the approach in the first place. The DL crew probably doesn't have much exposure to SFO, and they may have felt uncomfortable with the close spacing (much closer than just about any other airport I know).

--Mark Rogers

Ocn Vw 1K

Until Mark "comes up on the freq", let me add 0.02 of my ATC knowledge here. Bay Approach (Bay) often refers to the specific runways each pair of planes has for the benefit of both: "United xxx, you're for the left, Delta on your right is for the right." If Bay Approach used the phrase, "parallel", rather than the more precise, "left" , "right", that could have made the DL capt. less than comfortable as the aircraft stayed abeam. DL also could have been concerned if, as sometimes happens on a longer approach, Bay or SFO Tower might change a plane to the other runway. Remember, UA accepted a visual approach and if DL was also on a visual, then might have had more of an expectation that the aircraft were primarily responsible. I suspect that this was more of a reaction of the individual captain and not the Company's policy, and not necessarily a reaction (only) to UA. Perhaps the DL Captain does not fly as often into SFO as the typical RNO rocketeer and is more sensitive to the thinner separation of the 28s. The reverse applies to ATC with foreign pilots. SFO & Bay will be careful with certain carriers to make sure they understand the SFO approach jargon before pairing them up for simultaneous approaches.

FullFare

Mark: Thanx for a scholarly explanation. Good piloting, as always.

------------------
AAExecPlat; Lifetime AAirpass; 3MillMiles; UApremier-PassPlus

cblaisd

I believe he was. The controller asked him a couple of times if he had UA traffic in sight, and told him the UA would be landing "on the parallel" and to maintain separation.

Quote:

<font face="Verdana, Arial, Helvetica, sans-serif" size="2"> it would be impossible to do this if the A319 passed behind, and it would be impossible to slow below approach speed, thus prompting a go-around.

Don't know here. As either a pilot (a lapsed and thus not-at-all current private pilot albeit) or a pax (I was sitting in 1D on this flight), I have never seen such perfectly synchronized base-to-final turns.

Quote:

<font face="Verdana, Arial, Helvetica, sans-serif" size="2"> Alternatively, the DL crew could have just felt the aircraft were too close regardless, and initiated a go-around.

That was certainly the sense I got from the DL pilot's comments.

Quote:

<font face="Verdana, Arial, Helvetica, sans-serif" size="2"> Even at SFO, it's fairly rare to be exactly abeam another aircraft; usually you're staggered a few hundred feet and the trailing aircraft is responsible for ensuring visual separation.

That's what I thought too, and so was suprised when they were indeed exactly abeam for several miles, given the differences between the two aircraft.

Quote:

<font face="Verdana, Arial, Helvetica, sans-serif" size="2"> As far as I know, DL does not have any different procedures for parallel visual approaches than anyone else. If they did, they likely wouldn't have accepted the approach in the first place. The DL crew probably doesn't have much exposure to SFO, and they may have felt uncomfortable with the close spacing (much closer than just about any other airport I know).

Given the slightly staggered times the DL and our UA flights were coming and going from Approach and Tower freqs, I wonder if the DL pilot got the word of the parallel traffic after having accepted a visual approach. In my conversation with the two UA pilots, they did also say, I recall now, something about the approach controller may have put DL on final in a spot that wasn't the best.

Thanks much, Mark, for your quick and most helpful response. It is appreciated and lots of us really are grateful to have your expertise here!



[This message has been edited by cblaisd (edited 04-02-2002).]

Mark Rogers

That is probable. Once the DL 757 had reported the airport in sight (or the San Mateo Bridge on one of the charted visuals - e.g. FMS Bridge 28R), they would have been cleared for the visual approach. Later, they would be asked if they had the other traffic in sight, and when they did, they would be instructed to maintain visual separation. This is one reason flight crews are slow to report other traffic in sight at times. If the DL 757 was uncomfortable with maintaining visual separation, they could have not reported the other traffic in sight, leaving the responsibility for separation to the controller. Of course, if the 757 had been far enough ahead, the controllers could have just had the A319 maintain visual separation. If this were not possible, the DL 757 would have either had to eventually report the traffic in sight, or be broken off from the approach by ATC. My point is only that it is commonplace for aircraft flying the approaches to SFO to delay reporting other aircrft in sight until they are comfortable maintaining visual separation. Of course, a go-around is not a major event, and is certainly recommended if the crew is not comfortable with the approach. There might even have been other factors involved, such as initial line experience for one of the DL crewmembers.

--Mark Rogers

couscous

Interesting subject...I have wondered many times landing at SFO how uncomfortable some pilots must be with others aircrafts so close from theirs.... Thanks Mark...

househead

This last Monday, I flew in ORD to SFO and our UA 747-400 landed pretty much simultaneously with a KLM 747-400. It was quite a sight to see with the other plane right next to us. Captain announced on the intercom a couple minutes before landing to let everyone know that he was aware of the plane next to us, and that we were going to be landing on separate runways, and not to worry...

-househead

midway7

Did this 3-4 years ago while flying a Shuttle 735 up from LAX. We were on the left and a DL L10 was on the right. Incredible experience. Have a great picture of the L10 too.

The DL pilots were following the ultimate rule of thumb - the final decision lies within the pilot in command. He probably did not like it - so he pulled off it. I rather them be safe than sorry...