FOQA erroneous detections

[saraceno]

I just received an email from my company telling me l exceeded the stablized approach criteria. Foqa registered a descent rate greater than 1500 feet below 500 feet. It never happened during the flight, when l read the email l thought it was a joke, my first officer called me right after he read the email, we both were confused. Can any engineer or expert tell me how this can happen? Thanks

[wiggy]

No idea. Do you have the option to go into the office and see the trace and/or a replay of the approach ( FWIW we do)?

[galaxy flyer]

Makes me glad I'm not an airline pilot!

[Machinbird]

Can any engineer or expert tell me how this can happen? Thanks I am definitely not an expert on FOQA, but viewing this incident as a piece of an information system output, it is entirely possible that the wrong record was identified to your flight.
It may be someone else's problem.

[Amadis of Gaul]

I just received an email from my company telling me l exceeded the stablized approach criteria. Foqa registered a descent rate greater than 1500 feet below 500 feet. It never happened during the flight, when l read the email l thought it was a joke, my first officer called me right after he read the email, we both were confused. Can any engineer or expert tell me how this can happen? Thanks
This is the first I hear of FOQA department sending emails about anything...They usually use different channels, but I digress...

It's not entirely impossible to momentarily hit a high descent rate down low (or to have an erroneous VS indication), which is why I'm surprised that your flight got tagged based on that one parameter. Usually FOQA doesn't flag a flight unless a number of parameters were exceeded.

So, I guess my question would be what more there is to the story here...

[safetypee]

VSI, rate of change of pressure altitude, or radio altimeter ?

Wind speed, gusts, both pressure altimeters on the same pressure setting ?

Compare with previous flights in the same location.

Data source, recording rate, accuracy, analysis software ?

Aircraft configuration, change in flap / gear, yaw / roll (airflow - pressure crossflow between sensors) ?

[Tu.114]

As far as I am aware, those flight data monitoring systems are highly customizable by individual airlines and their trigger values are subject to change as needed. If a certain setup shows a lot of false warnings, it may well be adjusted not to raise unwanted false alarms any more. This has happened more than once already. It also may find it hard to differentiate between a bog standard Cat I ILS or a more taxing approach, say, with a glideslope angle of 5° that obviously requires sink rates greater than standard, even more so when correcting a slight deviation like 3 whites/1 red. It is is one of the analysts jobs to filter such unwanted alerts out and not tarnish the system by pestering the crews with heaps of unwarranted envelopes.

That said, the other side of the coin is that such a system may take note of exceedances that happened only for a fraction of a second and were immediately corrected. It has also been said that several crews that have been invited for a reenactment of the flight phase in which the system fired a warning were rather surprised at the situation in retrospective; it did not seem all that interesting to them while it occurred.

It is hard to deliver a diagnosis here. It may well be that the collected data is erroneous; that theory might be verified by checking several of the individual aircrafts flights around the one in question for occurrence of the same finding. It is possible as well that we are talking about an approach here that has a certain tendency or even an approval for higher sink rates while still being formally stabilized. Also, there have been findings from that system that looked weird in isolation, but a synoptic view with more data from that flight showed it to be perfectly normal.

[Max Angle]

I am definitely not an expert on FOQA, but viewing this incident as a piece of an information system output, it is entirely possible that the wrong record was identified to your flight.

Exactly that happened to me about 10 years ago, resolved very quickly by the flight safety manager who was very embarrassed by the whole thing so definitely worth checking.

[victorc10]

I had an e-mail last year saying I had busted the landing gate and landed, they noted I had filed an ASR, my reply was that on that date I was at home enjoying a Beer so it was more than likely someone else. They had got it wrong and apologised profusely.

[The Dominican]

Those systems do record erroneous data from time to time...., a couple years ago I had a notification that the flap 30 speed had been exceeded......, we were at .81 and FL390 with the flaps up (of course) when it registered the overspeed...., go figure!

[vapilot2004]

I would just add to the above that you should request to see the entire record. In our experience, instantaneous readings can (and do) go momentarily out of bounds - particularly when ADIRU is the source or when the bounds are triggered by an input that monitors analogue state changes.

Remember, computers make very fast, very accurate mistakes.

[PJ2]

Normally, "instantaneous" readings, (data spikes or very short-term valid excursions) are filtered by the design of the FOQA Event usually by requiring a certain amount of time, say 3 seconds for example for a high-rate-of-descent Event, to ensure that that's what was going on, and it wasn't just short, transient, ("going through the red light") value. Excursions occur all the time, and, particularly if the approach is rapidly re-stabilized, our program leaves such excursions out of the data. We call crews, we do not send emails and the discussion is a welcome one as the crew is often as curious about what FOQA shows as we are about learning from the occurrence.

Also, I am a very strong believer in pilot-run FOQA programs, or at least having active line pilots watching the data on a regular basis and doing the crew contacts under the direction of the FOQA Program Manager. I know this is may seem unrealistic to many but in my experience, (running FDM since the late 80's and flying the line), avoids many of the pitfalls like the one being cited here.

FOQA Programs need to be tailored to the airline's operation and designed and implemented to reflect the air carrier's safety culture. To reinforce something stated above, there are as many ways to do flight data monitoring as there are programs and no two are alike.

[Zaphod Beblebrox]

Have you ever seen a radar altimeter just go nuts for a few seconds. I have seen it and it caused the same thing and I got a call from our FOQA gate keepers, (pilots) and he said forget it. He just had to call and later he followed up that the next day the captains radar altimeter failed and had to be replaced.

It happens.

[Tee Emm]

If ever you get called up for tea and bikkies over an alleged CVR transcription event and the transcription is shown to you on paper, make sure you demand to hear the tape from which the transcription was made. in other words don't take what was written down as what was really said.

A pilot was accused of being impatient on the radio and a violation filed using the written transcription by a clerk in the DCA (Australia) accident investigation office as evidence. Three R/T transmissions by the pilot was offered as evidence. One was "Request Airways clearance" but written down as "are we clear"

Another was "Ready 30 seconds" which was an authorised terminology in AIP meaning we are ready for take off but need 30 seconds in the lined up position.
The investigating official used that transmission as evidence the pilot was in a hurry and therefore impatient.:confused:

[saraceno]

I really appreciate the replies I received, l forgot to mention that my employer is an Asian carrier, having said that, pilots who work or have worked in this part of the world know what l mean, common sense is a very rare commodity here. I had a meeting with my chief and to put it in a nutshell, my conversation could have been more productive if l had it with a wall. Next week l m going to review the data with the foqa team, l requested an hearing. Thanks again to all of you

[Sidestick_n_Rudder]

All I can add is that when I did FOQA, every flight that had been flagged by the computer had to be reviewed by me (the FOQA pilot) and if the parameters didn't make sense, it was immediately binned. Almost 30-50% of flights that have been flagged by the FOQA system were "false positives" and separating the chaff was a big part of my job...

Then again, it was in an European company. I too know first hand how sometimes things work in Asia... :ugh:

If you get the chance of seeing your flight's record, check for consistency with other parameters, like pitch, thrust, speed, radio altitude change, G/S deviation etc. if you really had 1500ft/min sink rate on approach, the other parameters would show too. Good luck!

[aterpster]

gf:

Makes me glad I'm not an airline pilot!

For the U.S. airline pilots this is one of areas where ALPA, APA, et al, are very effective.

[SunLord]

From AC120-82, this seems to be a High Descent Rate exceedance. The basic algorithm should be "Descent rate > x fpm for x seconds", so if properly implemented, you can rule out transient instrument errors. Would suggest checking what the monitoring window is for this event and if possible the FPM and altitude plotting for this particular descent. Since your FDM software has the data, I would guess it should be readily available for your review.

This is my first post in this forum, I am an engineer getting started with FOQA implementation for our product.

[PJ2]

aterpster, re "For the U.S. airline pilots this is one of areas where ALPA, APA, et al, are very effective.":ok:, and, I will add, also with air carriers in Canada.

[Airbubba]

I am definitely not an expert on FOQA, but viewing this incident as a piece of an information system output, it is entirely possible that the wrong record was identified to your flight.
It may be someone else's problem.

I had an e-mail last year saying I had busted the landing gate and landed, they noted I had filed an ASR, my reply was that on that date I was at home enjoying a Beer so it was more than likely someone else. They had got it wrong and apologised profusely.

Exactly that happened to me about 10 years ago, resolved very quickly by the flight safety manager who was very embarrassed by the whole thing so definitely worth checking.

I've certainly had that experience myself. Got a call from flight ops about a flight operated by a near namesake with a similar surname. I was concerned by the initial tone of the call but when they told me the sector, I realized that it was one that I didn't operate. I couldn't resist reeling in the hapless management pilot a little when I told him that he would have to drop my next trip with pay and then I would come in to discuss the situation on my assigned duty days, not my days off. He repeatedly emphasized that any counseling and training offered was totally non-punitive. I quickly resolved the issue by giving my employee number, he agreed that it wasn't me and was apologetic. And I sure didn't want to jerk him around too much because someday it might really be me at the end of that long green table with no ashtray. ;)

I'll observe that over the years these safety monitoring programs always seem to start out as 'totally non-punitive' and sometimes morph into something else. I believe the NTSB has already come out in favor of random CVR auditing and cockpit cameras. I'm sure when these innovations come we'll be similarly assured that any information garnered can never be used for punitive purposes.

Have you ever seen a radar altimeter just go nuts for a few seconds. I have seen it and it caused the same thing and I got a call from our FOQA gate keepers, (pilots) and he said forget it. He just had to call and later he followed up that the next day the captains radar altimeter failed and had to be replaced.

A couple of decades ago two of my colleagues were accused of flying under a bridge on a night visual approach to a West Coast airport, perhaps PDX or SFO, I'm not sure. Some nimby volunteer noise warden called the FAA to report the sighting and the feds took a look at their radar data. Sure enough, one of our planes showed a very low altitude on final over the water although the time seemed to be a couple of hours off. Don't know if they were able to get the data from the plane's FDR or QAR but it turned out that the Mode C encoder on that aircraft was intermittent. Apparently the controller made a remark to that effect but perhaps the crew didn't write it up at an outstation back in the day.

[halas]

Got an email two years ago for failing to stow thrust reversers for 50 seconds after application at an African destination.

Screen shot of my roster pointed out l was in SFO at the time.

Apology came back. Thing was, it was me, wrong date :)

[Uplinker]

Makes me glad I'm not an airline pilot!

Obviously I can't see your face to know if you're joking, but none of us should be concerned about FDM (FOQA).

If we are flying the company's aircraft the way we have been trained and asked to do, we need not worry. If something happened that took us outside normal company limits, and we recovered the situation - perhaps by going around and making another approach - then we should not be concerned, particularly if we tell the management about it before they see it in the data.

My boss once phoned me some days after I had gone around and asked me what happened. His tone suggested he was expecting a long convoluted excuse, so when I said, "Oh that's easy to answer; I cocked it up" (I was too fast on approach at the stability check gate). There was a pause and then the mood lightened considerably. He started laughing and said, "Oh, OK, well try not to do it again, bye !".

If pilots are flying outside the limits, then it is only common sense that reasons must be found. There might be training issues that the company has not spotted, and if a trend is noticed they can train against it. If pilots are flying like cowboys, then they need to be reined in.

The key is, most bosses find it uncomfortable to give you a bollocking, and having to do so puts them in a bad mood to start with. So if you cock something up, then 'fess up to the boss and/or write an ASR before they get the call from FDM department and have to pick up the phone to you :ok:

Erroneous data needs investigating too, but again, we should not be overly worried about this.

[Piltdown Man]

Bum numbers are regular visitors in FOQA data centres. I'm not sure how they sneak in but their certainly do. So when exceedences are flagged they have to viewed in context. Overspeeds for example. If aircraft cannot accelerate and decelerate in fractions of a second. Unless of course there was significant windsheer. The windsheer can be detected from ADC data. Without windsheer, the airspeed exceedence can be ignited. So what I'm saying is that the value of a single parameter is not significant for a short period of time and any exceedence has to be viewed in context.

In your case, a ROD in excess of 1,500 FPM so close to the ground would be a memorable event. So if that didn't happen, the questions have to be:

1. What was the airspeed before, during and after the event?
2. What was the thrust setting before, during and after the event?
3. Where you fully configured?
4. What data was used to calculate ROD? Baro or calculated radio closure rate? The latter can be affected by too many other factors.
5. Why didn't the EGPWS chime in?
6. What sort of approach? If it was an ILS, then providing the glideslope was maintained and the airspeed remained constant then the ROD would have to have been constant.

Take a calculator, pen and paper to the repay. You may well have to do some maths.

Best of luck.

[Piltdown Man]

Regarding my above post, I'm assuming the data is for the correct date, flight number aircraft registration, location and you actually operated the flight in question.

[Airbubba]

My boss once phoned me some days after I had gone around and asked me what happened. His tone suggested he was expecting a long convoluted excuse, so when I said, "Oh that's easy to answer; I cocked it up" (I was too fast on approach at the stability check gate). There was a pause and then the mood lightened considerably. He started laughing and said, "Oh, OK, well try not to do it again, bye !".

If pilots are flying outside the limits, then it is only common sense that reasons must be found. There might be training issues that the company has not spotted, and if a trend is noticed they can train against it. If pilots are flying like cowboys, then they need to be reined in.

Where I've worked in recent years you never get a call about going around, you get a call if things weren't right and you didn't go around.

I've been around long enough to remember the 'cowboys', legends in their own mind who wouldn't use checklists and flew Space Shuttle unspooled approaches in a 727. :eek: 250 to the marker and configure on the way down. Or, the 'tower watch this' zoom climb takeoff with pax onboard. :mad:

FOQA and some of those other acronyms have cleaned up the business and made things safer, but perhaps more paranoid, for us all.

A few years ago we were sometimes flight planned at near our maximum Mach number to keep the crew duty day within limits. In smooth air no problem, Mr. Boeing builds a stable airplane. However, a few bumps (e.g. over Japan) or a temperature change and you could easily overspeed slightly and get the EICAS and aural warnings. Open the speed window, dial back a few knots, problem solved.

At some point the feds decided that even a momentary overspeed warning was an 'exceedance' and needed to be logged and investigated as an incident. There was some verbiage in a systems manual that said the warning came on several knots before VMO/MMO but the inflight activation of a warning system required a maintenance writeup, a signoff and an operations report. Obviously I didn't want to spend my layovers trying to type an explanation into a computer form so I backed off the speed a bit to avoid the warning.

Did this make the operation safer? I'm not sure but I have found myself worrying about what went on the FOQA record and doing a go around because I was stable at 800 feet but not at 1000. Or delaying a takeoff because I didn't have data for the intersection in use even though the numbers for an upwind intersection with less runway looked good. Years ago folks would laugh at those decisions but now things are much more CYA in my observation. And, maybe I have more of a conscience knowing that any decision I make is recorded and subject to review, sometimes weeks later.

[saraceno]

First of all l would like to thank each one of your messages, very good points. So l asked to review the data and to me it looks like a clear updraft, no egpws activation, no airspeed change, no glide slope deviation, no change in thrust and fully configured for landing well before the event was registered. My main point to my chief was that in order to have a rate of descent of 1500 feet per minute and no glide slope deviation, our ground speed should have been 300 knots. He was not interested to the facts, l guess he was sticking to his alternative fact, one only, rate of descent 1500 fpm. My first officer, local guy, thought he could persuade them, not interested either. I personally thing FOQA has improved safety overall, but unfortunately the use of it sometimes has created an histeric paranoia between pilots which often becomes the problem and not the solution. Thanks again to all of you.

[Piltdown Man]

Thanks for the update. It looks like you are working for a bunch of ignorant half-wits who cannot and must not be trusted. I also fully agree with you that idiots like your chief will create a vast chasm between the office and line pilots. Incidents like this will prevent them from ever improving their workforce's abilities because they have broken the trust that has to exist between the two sides for this to occur. A few more smoking holes I'm afraid.

[PENKO]

For what it's worth, I once had a printout on landing stating that we had just made a severe hard landing. We looked at each other in amusement because as far as greasers go, we just made one of the better ones! Called up maintenance control who just shrugged it away stating 'it happens sometimes, probably a glitch in the system just as you touched down'. They would of course follow it up with other flight data, which I am sure showed that we made a very safe and ordinary landing, because I never heard anything of it again.

So yes, it does happen that the systems flag an event which you know never happened. Hopefully other objective data will back you up if you work for an outfit who will not give you the benefit of doubt.

[gerago]

This was probably KAL. A friend got hauled up because he took over from the local F/O who flared high, touched down at 2300 ft down a 13123 ft long runway at Vref-12 kts. Why, because he did not land before the 2000ft mark and he touched down below Vref-10! There was some windshift down at the touchdown zone...they didn't want to know or even care. Why dob him for landing at 2300 ft when it was within the 3000ft zone? Their answer, there was a " worrying uptrend of people landing beyond 2000 ft of late "!

After much arguments and several trips to the " OC ", he was off the hook. But they flagged him, got the checkers ( LCPs ) to breathe down on him on his line checks and even badmouthed him to the Boeing Sim guys!

Still wanna work for those nit-wits??? Life style commuting contracts? Give me a break. When things go bad, they can really go very bad over there.

[Dan Winterland]

The People's Republic of China was one of the first countries to have FDAP/FOQA. However, the way they use it is very different to those with more enlightened flight safety. In some PRC companies, pilots earn 'demerit points' from the flight data. Often the first they know there's a transgression is that they see their pay being docked! It's policing by data and although it does make the guys follow the rules, the issue is that they guys know the data parameters and will fly to them. They also know what they can get away with as it's not a parameter.

The net effect is a poor safety culture with no-one willing to report voluntarily and which means those errors not captured by the data (such as taking off with incorrect performance calculations) will never be known about. Until perhaps there is an accident - and even then the evidence may not be proved.

It's a poor way of using flight data and very ineffective. It's common in Asia and it's clearly the policy at saraceno's employer.