Laser pointer to detect wing ice?

[FL420]

Does anyone have any experience with or knowledge of the technique of using a handheld laser pointer to detect frost or ice on the top of a wing during preflight inspection? How about from the cockpit inflight?

I remember hearing or reading something several years back about someone recommending it. Supposedly the presence of ice causes the light beam to disperse or attenuate. I haven't been able to track down any specifics online.

 

[sleddriver71]

Never heard of using the laser pointer. What's wrong with a flashlight? It's always worked fine for me (better than an ice light on the Seneca's and Chieftains). It's not that hard to see or detect. A drop in airspeed is usually a good indication too.

 

[sky37d]

A little change in attitude, pitch, is a good indicator, too.

 

[FL420]

Okay. To be more specific. A laser pointer was reported to be useful to detect a layer of clear ice on the top of a wing before flight. A layer which may be difficult to see because it's clear and difficult to feel because it's smooth.

 

[Dr Pokenhiemer]

If you can't tell if there's ice on the wing on your PREFLIGHT, maybe you should stick your tongue to it! Who needs a laser pointer----maybe the guy in the Sporty's book--the one with the head thing that holds 2 mag lights.

 

[Gorilla]

You guys are missing his point. Clear ice on, say, a B777 wing can be difficult to detect. Touch it? Stick your tongue on it? Good luck, unless you're 20 feet tall, or drive a cherry picker on your walkaround. Not everyone flies Lears.

The MD-80 had a well-known clear ice problem due to supercooling of the wing fuel, followed by descent in even very light moisture. We had to climb a ladder and rub a PVC pole onto several texture strips to detect the ice on top. We also had to attempt to view surfaces from the AC cabin. I've detected clear ice in this way that would have been very difficult to detect in any other fashion.

I like this idea and see how it can be valuable. The scattering effect of the ice would be pretty obvious, although you'd need a powerful laser, maybe one of those green jobs.

 

[91100 100 set]

With all the hoopla lately with laser pointers and aviation, have fun trying to explain it's purpose to the overzealous TSA screener who finds it in your bag.

 

[Comin-In-Hot]

I don't know kid, magic tricks and laser swords are no match for a good blaster at your side.

-Han Solo

 

[FL420]

You guys are missing his point. Clear ice on, say, a B777 wing can be difficult to detect. Touch it? Stick your tongue on it? Good luck, unless you're 20 feet tall, or drive a cherry picker on your walkaround. Not everyone flies Lears.

Exactly. I can't remember the last time I flew anything small enough for me to touch the bottom of the wing, much less the top.

The MD-80 had a well-known clear ice problem due to supercooling of the wing fuel, followed by descent in even very light moisture. We had to climb a ladder and rub a PVC pole onto several texture strips to detect the ice on top.

I cringe everytime I see a Mad Dog pilot at the next gate climb up that rickety, icey aluminum ladder to check the top of the wing.

I like this idea and see how it can be valuable. The scattering effect of the ice would be pretty obvious, although you'd need a powerful laser, maybe one of those green jobs.

IIRC, a small red classroom type laser was used. Whether you are responsible for the safety of just one or more than 200 trusting souls you owe it to them to use all the tools available to you to get them off the airplane in as good a shape as they were when they got on.

 

[Thedude]

A little change in attitude, pitch, is a good indicator, too.

Its probably too late by then

 

[siucavflight]

Its probably too late by then

Why is that? A little change in attitude to hold altitude would be a very good indicator to a icing problem.

 

[FN FAL]

With all the hoopla lately with laser pointers and aviation, have fun trying to explain it's purpose to the overzealous TSA screener who finds it in your bag.

Or what about all the FBI agents coming to your house after some licktard reports seeing it being shone about while he's departing or arriving the airport?

They prosecuted that one guy in NJ under the Pat-Riot Act for shining a laser around where a pilot could see it. I could imagine that it wouldn't be to hard to get a pilot convicted for the same thing, even though he was just looking for ice on his wings.

All it would take is an inadvertent shining up in the sky or a reflection off of something on the plane and there would be some 'splaining to do if that went badly. Considering recent events with pilots and federal grand juries, pilots might want to learn their 5th amendment a little better than they do now, if they wan't to pursue shooting laser lights around an aerodrome.

 

[KeroseneSnorter]

I don't know kid, magic tricks and laser swords are no match for a good blaster at your side.

-Han Solo

Rroowwwwaaahhhh.

-Chewbacca

 

[Thedude]

Why is that? A little change in attitude to hold altitude would be a very good indicator to a icing problem.

I am making the assumption that we are talking about transport cat a/c. The majority of these a/c have anti-ice leading edges and not de-ice type boots not to mention the auto-pilot is normally on for approx 90% of the flight and also have a fairly wide load operating envelope (read trim required for flight). If you got into icing severe enough to notice a pitching moment, I dont think the anti-ice would be enough to correct the problem. Having flown large t'props with de-ice boots for a number of years, I never noticed a pitiching moment that was unusual. Once, I did see tha airspeed bleed off by a few knots and when we emerged from the IMC and we were carring a fairly large load of ice but no pitching moment. Little airplanes are another story and I haven't flown one in quite sometime.

 

[FN FAL]

I am making the assumption that we are talking about transport cat a/c. The majority of these a/c have anti-ice leading edges and not de-ice type boots not to mention the auto-pilot is normally on for approx 90% of the flight and also have a fairly wide load operating envelope (read trim required for flight). If you got into icing severe enough to notice a pitching moment, I dont think the anti-ice would be enough to correct the problem. Having flown large t'props with de-ice boots for a number of years, I never noticed a pitiching moment that was unusual. Once, I did see tha airspeed bleed off by a few knots and when we emerged from the IMC and we were carring a fairly large load of ice but no pitching moment. Little airplanes are another story and I haven't flown one in quite sometime.

Since you haven't learned anything since Roselawn, maybe you ought to save your own life and others, by staying out of "little airplanes".

The manufacturer indicated that the airworthiness directive was not incorporated into the Saab 340 manuals due to disagreements concerning the applicability of the information to the Saab 340. They also indicated the airworthiness directive was applicable to US operators only.

CASA did not impose the requirements of airworthiness directive 96-09-21 to flight manuals of the Saab 340 because the state of manufacture did not issue it. CASA stated this was in accordance with the standards and recommended practices of ICAO Annex 8 – Airworthiness of Aircraft.

The investigation team found however, that the airworthiness directive had been implemented in the flight manuals of other turboprop aircraft, either by a manufacturer’s amendment or a flight manual amendment issued by CASA.

In this occurrence, analysis of the recorded data showed that as the aircraft speed decreased, the autopilot commanded an increasing amount of nose up elevator to maintain altitude. Commensurate with this, the trim was also progressively increased nose up by the autopilot.

For further information on recorded data refer to section 1.11 of this
report.​

FIGURE 1:

Shows the movement of the pitch trim in the time leading up to the occurrence.

http://www.acpa.ca/safety/vh-lpi.pdf​

 

[Thedude]

Like I am gonna take advise from a guy that that doesn't have any significant time in anything bigger than a C-208

Maybe I should just re-state, by the time you notice a pitch changing moment...its probably to late.

 

[FN FAL]

Like I am gonna take advise from a guy that that doesn't have any significant time in anything bigger than a C-208

Maybe I should just re-state, by the time you notice a pitch changing moment...its probably to late.

Well, I got a quarter inch of ice x three legs yesterday and I didn't give up. It's not too late to get on the winning team, son.

 

[DrewBlows]

The MD-80 had a well-known clear ice problem due to supercooling of the wing fuel, followed by descent in even very light moisture.

Does the ice usually melt when fuel is added (assuming the temperature is above freezing)? I heard that there could be ice even in the summer (Super 80's in DFW), do you guys deice in July?

 

[Gorilla]

Does the ice usually melt when fuel is added (assuming the temperature is above freezing)? I heard that there could be ice even in the summer (Super 80's in DFW), do you guys deice in July?

I haven't flown 80's in a while. The phenomenon can occur at temps well above what would normally get your attention for ice, such as high 50's or low 60's on the ramp. Above a certain ambient temp, it wasn't an issue. Adding fuel often didn't do enough to melt the clear ice; it depends upon how much super-cooled fuel is still in the wings, and how much is added on the ground. Long cruising at high altitudes, followed by a quick turn in 50 to 60 degree moist ramp weather, would often cause significant ice.

They've added electrically-heated blankets at strategic locations on the wing skin, at least on some (or all) AA aircraft, not too sure about other MD-80's. The blanket eliminates the problem. It consumes huge current and is one of the first items load-shed when there's not enough power on the aircraft.

Maybe a current MD-80 guy will add to this or correct me.