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EFVS in 737NG

Old 08-14-2023, 10:12 AM
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Question EFVS in 737NG

Hi Pilots,

So, as you can see by my nickname, I am not a pilot. However, I have a very specific question about EFVS, EVS, and landing with such technology.

I've read some articles about EFVS, so these are my current assumptions (please let me know if I am wrong):
So there have been several airplane manufacturers like Bombardier, Gulfstream, and Dassault that equipped their newest airplanes with HUDs and EVS from Collins or Elbit. As I've understood it, HUD and EFVS are very common in military aircraft, but up until a couple of years ago, it was not common for a Gulfstream to be equipped with such a system. The benefits are enhanced vision in CAT3 weather (I hope that's the correct category for bad weather; I mean, like really bad weather with minimum RVR). I understand that it may make sense to equip private jets with such technology as they may land in airports that don't have other safe landing infrastructure.
I found that EFVS is part of the FAA regulation:
However, I don't understand if EFVS will be mandatory for big commercial airplanes like the 737NG or 737 Max. Unfortunately, I could not find any information on whether 737s are already equipped with EFVS.

My questions:
Is EFVS mandatory in the States or in Europe?
Do you find any benefit in using EFVS while landing?
Are there other systems onboard that provide you with the same safety and information as an EFVS? (Like, do you really need it or is it just a gimmick for bad weather if you are about to land at a local Chilean airport?)
Do you think airlines see a benefit in EFVS?
Would retrofitting a 737NG fleet with EFVS even make sense?

Thank you in advance for your support!
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Old 08-15-2023, 10:21 AM
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This is my understanding, not 100% sure it's all correct...

It's not mandated for US 121, and never will be for retrofit. It might possibly become standard or even mandated for future new aircraft.

It's a additional cost, complexity, and maintenance. Also will need regular database updates since you don't want to fly down with a synthetic image of the runway environment in summer and then have to transition to a view of real world winter for example.

As you say it may have more utility for bizjets that flt into smaller, less-equipped airports. Some US airlines were early adopters of HUD technology since they fly into smaller, remote, less-equipped fields... those might go for synthetic vision.

Also training... depending on how good it is, it might require significant additional pilot training to use in low-vis, and that would probably include on-going recurrent training (more cost). 121 is pretty good with CAT 11/CAT III autoland approaches, we're already trained and comfortable doing that and don't need to see the runway before we arrive. There do not appear to be any safety issues with CAT II/III for the most part. Again, it could be helpful at smaller airports.

So it will probably come eventually but there's no rush to spend the money on retrofits for most 121 operators.
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Old 08-20-2023, 02:08 AM
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Thanks for your insights!

Do you know if there is any publicly available database about airports and each airports distinct landing infrastructure? Like I want to find out how many airports that can service a 737NG that don't have CAT II/CAT III safety infrastructure.
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Old 08-20-2023, 06:03 AM
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In large biz jets, EVS has been common for, at least, 15 years. I was using EVS in a Global XRS in 2008. There’s training and recurrent in the sim has one EVS approach to minimums. The limitation is it’s dependent on an IR image—hear differentials. Works great in some types of fog, smoke, haze. Wet snow, depending on droplets size some fog, very heavy rain, not so good. I went into Delhi in early morning, reported viz around 500m, on EVS I had the lights and airport clear at 6 miles all the way to touchdown. Even helped taxiing in, warm human marshallers show up well in 50F temps. The Pilot gets the EVS (IR) image with the HUD data superimposed on it. Takes some practive to use it easily. I always taught “use the HUD/EVS every landing”. If you use it on a low weather day, you’ll be worse shape than without it.

Synthetic vision isn’t there yet for a sole landing supplement, proving the databases are accurate, satellite availability is the issue. Probably a combination of microwave radar, synthetic vision from terrain database and IR will be the future. Speaking of synthetic vision, arriving in Rio de Janeiro one night, all very comfortable with a 15” screen full of flight data superimposed on the “picture” of the approach, lose a satellite and back to no picture instantly. The system needs a minimum number of GPS satellites to ensure accuracy and integrity. Once accustomed to SVS, it’s a crutch.
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Old 08-21-2023, 07:51 AM
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Originally Posted by ImNoPilot

Do you know if there is any publicly available database about airports and each airports distinct landing infrastructure? Like I want to find out how many airports that can service a 737NG that don't have CAT II/CAT III safety infrastructure.
Are you looking for something like this?

That database will give you numbers on types of approaches in the US, including lower minimums programs (cat II, III, etc). It won't tell you what airports can service a 737. When you say "service," what do you mean? Ramp weight bearing capacity, FBO space, fueling or air stairs or lav waste truck? Towbars?

Cat II and Cat III approaches aren't so much about safety as they are about operations; they enable approaches and landings with lower visibility minimums, and lower approach altitude minimums, than other types of approaches. What they do is allow an operator to continue operating legally into an airport when visibility and ceiling are too low to go there with other kinds of approaches. Airplanes capable of only Category 1 minimums, for example, might divert and go somewhere else, while the Cat II or Cat III aircraft may be able to get in.

Below certain minimums, autoland capability becomes necessary, which involves the aircraft, the approach procedure, and the crew; all have to be qualified. A requirement associated with lower minimums approaches is protecting the approach path and electronic areas from interference; many airports have ILS approaches, for example, but few have protections or programs to protect the ILS critical area, enough to qualify for the lower minimum approaches. That said, a trained crew and approved aircraft can conduct autolands at most airports, but at airports without Cat II/III authorizations, the higher minimums must still be respected so far as visual identification of the runway environment/approach lights, etc. Where autoland isn't advisable or possible, automation, training, and maintenance of the aircraft to a given standard is still a plus, and as others have noted, enhanced vision is still a useful tool under most circumstances. Like any such system, one must always keep in mind that from the cockpit, one is viewing a two-dimensional representation of what's outside the cockpit, not what's actually outside the cockpit. That distinction has bitten pilots before.

Enhanced vision, night vision, infrared, etc, add a great level of situational awareness to many (not all) operations, but also come with limitations, like any tool. I used to fly an approach to a runway in Iraq, which had an ILS, but had a place on the ILS that was well known for small arms fire; common practice was to offset the approach to avoid the location of the small arms fire (a village on a hill). Visibility at times would become sharply reduced due to sand, etc, and we were nearly always in the dark. The offset approach was enhanced considerably by heads-up infrared and night vision information which allowed a fairly clear picture of the runway and surrounding terrain and features, including threat areas. Not an issue for domestic flying in the US, but enhanced situational awareness, visibility, etc, are additional tools that increase the level of useful information available in the cockpit. There are many such layers that take us from old, traditional, limited cockpits, to where we are now, and no doubt there's far more to come, but anything that enhances safety is a good thing (or as noted above, can also become a crutch that leaves us handicapped, to a degree, when we're without). Thus, even without lower minimum procedures, products such as enhanced vision have merit and value so long as they're not the objects of over-reliance. Basic airmanship still counts, but all the tools, from enhanced vision to lower minimum capabilities, to ground proximity information, to the more advanced traffic information that we have today, and even better radars, coupled with far better cockpit displays that overlay larger screens and more horizon, with navigation information and so much more, all combine to give us the tools to operate more safely and efficiently with far greater awareness at nearly all levels; this is true whether we have a runway in front of us that's certified for Cat II/III, or not.
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Old 08-21-2023, 12:31 PM
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To the OP:
I don't know about other operations, but I suspect they are similar to ours. At FedEx, we have a HUD and EFVS on all our Boeing aircraft and MD-11s. This equipment has no affect on any CAT-2 or CAT-3 operations. Those are conducted using auto-land and most aircraft (absent MELs or other issues) are able to utilize the lowest published minimums down to 300/300/300 (75m/75m/75m) RVR. Flying these approaches is done the same whether the HUD/EFVS is used or not. Of course, there might be some enhanced SA on the part of the Captain (and FO using a repeater that's being installed), but that won't affect the outcome of the approach in terms of being able to land out of it.
The only benefits of the HUD/EFVS officially is on CAT-1 ILS and non-ILS approaches in the 50 US states, US territories and US military airports.
The planned use of EFVS allowed charted approach visibility minimums required to start an approach to be reduced to a lower "derived" value. For example, charted visibility requirements of 1 mile can be reduced to 5/8 of a mile.
If enhanced vision allows identification of the runway threshold and TDZ, it is allowable to continue to 100 feet above TDZE. At that point, it's required to identify the threshold, lights or markings of the threshold, TDZ or lights or markings of the TDZ using natural vision or a MAP must be executed. So the bottom line is that EFVS is really just a way to potentially get into a field that's only equipped with CAT-1 ILS and/or various forms of non-precision approaches (non-ILS approaches).
The other benefit involves use of the HUD (EFVS has no bearing) which allows a reduction in takeoff minimums for the Captain from 500 RVR to 300 RVR. This provision must be charted for the specific runway and there are only a handful of airports world-wide where this capability can be utilized.
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