I was watching Mayday, and they stated that the airbus autopilot has 2 modes to adjust the decent rate. One is to adjust the flight path angle, and the other being the regular vertical speed adjustment. I was wondering how I can use the airbus's flight path angle function? Ive never seen it before, and I think that would be a lot better then having to do the calculations manually. Does anyone know about this?

Hi, The HDG TRK/ VS FPV button can be found on the FCU just above the two autopilot switches. It is mainly used for manual flight and non precision approaches. For hand flying you can switch off the flight directors, engage FPV and handfly with a great deal of precision, you simply place the 'bird' ( a small symbol showing the aircrafts trajectory on the Primary flight display) where you want and the aircraft will fly the path, so for example if you need to fly a 3 degree glideslope simply place the bird on the 3 degree scale on the PFD. It is a great tool, I could go into a lot more but those are the basics. Best bet is to download an A3xx FCOM and have a read. Regards

Does anyone know about this?

Yup, it was in fact the poor labelling of that autopilot function which contributed to the crash of Air Inter Flight 148 in 1992 (this was when the Airbus was pretty new to most pilots and the understanding of such functions was less widely understood). As you noted, the MCP can be put in two different vertical speed modes: Flight Path Angle, or Vertical Speed, and originally on the Airbus A320, both modes displayed in a very similar way, which caused the crew of Air Inter 148 to dial in a 3,300 feet per minute descent rate whereas they thought they were selecting a 3.3 degree descent angle, which would be a much lower rate of descent. As a result they failed to clear some terrain and flew into a hillside in the Vosges Mountains whilst on long finals to Strasbourg, but the fact that they were flying at well over 250 knots below 10,000 feet certainly didn't help either, since they had little chance to react to any terrain warnings they might have got, or at least would have if Air Inter A320s had a GPWS system, which at that time they did not. The MCP on the Airbus family was subsequently modified as a result of that accident in order to display the two different modes in a much clearer fashion: VS now displays as a four-digit figure, FPA displays as a two-digit figure with a decimal point. What FPA will allow you to do is use the three-in-one descent rule in a much more intuitive manner amongst other things, and it will of course also let you fly a typical approach descent profile when completely independent of a glide slope lock, so you could for example use the feature to get into London City Airport if some ground aids were not functioning, since that has a steeper approach profile than the typical descent profiles found at most airports. It has proved demonstably useful for Airbus sales on occasion, because the Airbus A318 is one of the few twin jets that have been cleared to operate from London City Airport (for example where BA selected the diminutive Airbus with all-business class seating for its direct flight to the US from London City), owing to the need to demonstrate the ability to fly such steep approaches safely, which is a fairly long-winded certification process for an aircraft type. Al

...occasion, because the Airbus A318 is one of the few twin jets that have been cleared to operate from London City Airport (for example where BA selected the diminutive Airbus with all-business class seating for its direct flight to the US from London City), owing to the need to demonstrate the ability to fly such steep approaches safely, which is a fairly long-winded certification process for an aircraft type.

Its technically not a direct flight from LCY to the US. They stop in Shannon for about 45 mins to refuel , else they'd be too heavy to depart from London City. They do clear you through US customs at Shannon though, so its 45 mins well spent at least. Eastbound they do operate direct to London City from the US. Regards.Ernie.

Yup, it was in fact the poor labelling of that autopilot function which contributed to the crash of Air Inter Flight 148 in 1992 (this was when the Airbus was pretty new to most pilots and the understanding of such functions was less widely understood).

For the guys interested and since Alan brought it up.

THE MECHANISM OF THE ACCIDENT:After analysing the accident mechanisms, the commission reach the following conclusions:1 - The crew was late in modifying its approach strategy due to ambiguities in communication with air traffic control. They then let the controller guide them and relaxed their attention, particularly concerning their aircraft position awareness, and did not sufficiently anticipated preparing the aircraft configuration for landing.2 - In this situation, and because the controller's radar guidance did not place the aircraft in a position which allowed the pilot flying to align it before ANDLO, the crew was faced with a sudden workload peak in making necessary lateral corrections, preparing the aircraft configuration and initiating the descent.3 - The key event in the accident sequence was the start of aircraft descent at the distance required by the procedure but at an abnormally high vertical speed (3300 feet/min) instead of approx. 800 feet/min, and the crew failure to correct this abnormally high rate of descent.4 - The investigation did not determined, with certainty, the reason for this excessively high rate of descent . Of all the possible explanations it examined, the commission selected the following as seen most worthy of wider investigation and further preventative actions:4.1 - The rather probably assumptions of confusions in vertical modes (due either to the crew forgetting to change the trajectory reference or to incorrect execution of the change action) or of incorrect selection of the required value (for example, numerical value stipulated during briefing selected unintentionally) .4.2 - The highly unlikely possibility of a FCU failure (failure of the mode selection button or corruption of the target value the pilot selected on the FCU ahead of its use by the auto-pilot computer).5 - Regardless of which of these possibilities short-listed by the commission is considered, the accident was made possible by the crew's lack of noticing that the resulting vertical trajectory was incorrect, this being indicated, in particular, by a vertical speed approximately four times higher than the correct value, an abnormal nose-down attitude and an increase in speed along the trajectory .6 - The commission attributes this lack of perception by the crew to the following factors, mentioned in an order which in no way indicates priority:6.1 - Below-average crew performance characterised by a significant lack of cross-checks and checks on the outputs of actions delegated to automated systems. This lack is particularly obvious by the failure to make a number of the announcements required by the operating manual and a lack of the height/range check called for as part of a VOR DME approach.6.2 - An ambiance in which there was only minimum communication between crew members;6.3 - The ergonomics of the vertical trajectory monitoring parameters display, adequate for normal situations but providing insufficient warning to a crew trapped in an erroneous mental representation;6.4 - A late change to the approach strategy caused by ambiguity in crew-ATC communication ;6.5 - A relaxation of the crew's attention during radar guidance followed by an instantaneous peak workload which led them to concentrate on the horizontal position and the preparation of the aircraft configuration, delegating the vertical control entirely to the aircraft automatic systems;6.6 - During the approach alignment phase, the focusing of both crew members attention on the horizontal navigation and their lack of monitoring of the auto-pilot controlled vertical trajectory ;6.7 - The absence of a GPWS and an appropriate doctrine for its use, which deprived the crew of a last chance of being warned of the gravity of the situation.7 - Moreover, notwithstanding the possibility of a FCU failure, the commission considers that the ergonomic design of the auto-pilot vertical modes controls could have contributed to the creation of the accident situation . It believes the design tends to increase the probability of certain errors in use, particularly during a heavy workload.

Reference BEA f-ed920120. In short, it's a clear sign of some other, more psychological based, factors taking place if a pilot commands a 3.3 degree descent and then fails to see that his VS gets 'up' to 3300 ft/min while his GS would have made those 3.3 degrees just approx 800 ft/min (so they e. g. did not 'fly well over 250 knots below 10,000 feet', it actually ranged between 170 and 200 kts).As we are speaking about two pilots and also about the wrong vertical path being maintained for minutes, the thing doesn't actually get clearer.The rule is to set or command an AP change and then crosscheck if it is executed correctly. New to the plane, yes (162 and 61 hours), but new to flying (8800 and 3600 hours)? See some factors above. 'Pilot error' sadly summarizes quite brutally that there were factors in place to trigger a complete loss of situational awareness in that case. 3300 ft/min on the VS below 10.000ft should actually stress the need to regain some (the command for it actually was made being at only 5000ft MSL).That special Airbus also had a HUD in place, so the awareness on the instrument side (e. g. FPA display and VS readout) may even have been higher than normal, in theory, not to forget the deck angle differences between 800 ft/min and 3300 ft/min at speeds of 170-200 kts.But we don't know what happened in that cockpit, at that time. I'm just writing this because the lack of systems or their error (if present) can never be a way to explain why two professionals fly their working plane into a mountain range. One has to look at such things at a much wider, way beyond the glareshield, angle in my eyes. More on the topic, you see the FPA feature being available at other planes too, so it's not actually an Airbus special. You can e. g. use the E-Jets in the sim to get to know and use that neat stuff.The FPV display is present on even more airplanes.

Its technically not a direct flight from LCY to the US. They stop in Shannon for about 45 mins to refuel , else they'd be too heavy to depart from London City. They do clear you through US customs at Shannon though, so its 45 mins well spent at least. Eastbound they do operate direct to London City from the US. Regards.Ernie.

Yeah, I know they stop going one way owing to the prevailing winds and MTOW, but it was simply easier to type what I did on my post rather than stray off the point too far. Both that flight and the ones with similarly business-class outfitted code-sharing 737s making the trip across the pond from mainland Europe are some of the more unusual and interesting flights small airliners make these days. Wouldn't have fancied making that trip in a twin turbojet airliner a few years ago, even if it had been legal to do so back then! Al