Frost Downs a Mooney

[pelmet]

Its that time of year again.

Each situation is different but I had a frost issue the other day. Was just a lot of dew on the roof of car beside me where I parked when I arrived. But either all dew quickly froze over at the airport or the aircraft for some reason had frost while that other car did not.

The sun had just risen but the aircraft was in a large shadow from the hangar. Seeing as I only had a limited amount of time for my booking, I moved the aircraft to a location in the sun and positioned it pointing away from the sun to get maximum sunlight to melt the frost which happened fairly quickly. But the leading edge still had frost, so I re-positioned the aircraft to allow the rest of the wing to have the frost melted while I did the walkaround and extensive sign-out procedure.

I did do the run-up with the aircraft positioned to maximize sunlight on the wings but it can't reach all of the wing. It all worked our well but now that I think about it, I suppose all that wetness could have frozen again as the temperature probably had not warmed up yet.. Might be worth another check before taking the runway.

Any other interesting frost stories.

"C-GEAR, a privately registered Mooney M20J, was conducting a local flight from Oliver (CAU3),
BC with only the pilot on board. The pilot initiated the takeoff roll and, at approximately rotation
speed, the aircraft shuddered. The pilot rejected the takeoff but was unable to come to a stop on
the runway. The excursion off the end of the runway ended when the airplane collided with the
airport perimeter fence. The overnight temperature was -3°C and conducive to ice or frost
formation. There is an active radio-controlled model flying club at CAU3 and the airport has a
NOTAM in place to that effect. The pilot was not injured but the airplane was substantially
damaged.

Maintenance has inspected the aircraft. Parts are being ordered from the manufacturer and repairs
to the wings and spinner will be completed. The engine will be torn down, inspected, and repairs
will be made as required."

[digits_]

A little bit of a vague description to determine the airplane 'shuddered' due to frost on the wings.

Frost on the runway, if any, was likely a more important cause for this crash I'd say.

[pelmet]

A little bit of a vague description to determine the airplane 'shuddered' due to frost on the wings.

Frost on the runway, if any, was likely a more important cause for this crash I'd say.

Unlikely. Possible contributor if the runway was slippery but frequently there is frost on aircraft but not on the paved surfaces. Ground warmth, I would say. But even if there was frost on the runway, it is normal to operate from such a surface.

The aircraft was said to be at rotation speed. I suppose the ‘shudder’ could have been from something else. Any guesses.

[photofly]

Searching for takeoff and landing roll for an M20J, Google throws up 880 and 770 feet respectively.

CAU3 has one runway 3100 feet long, and sits at an elevation of 1100 MSL. With temperature around zero, we can be assured that density altitude wasn't an issue that day.

You can draw your own conclusions about an airplane that, given that data, is unable to accelerate to a normal rotation speed and then stop safely on a runway of that length.

[pelmet]

Searching for takeoff and landing roll for an M20J, Google throws up 880 and 770 feet respectively.

CAU3 has one runway 3100 feet long, and sits at an elevation of 1100 MSL. With temperature around zero, we can be assured that density altitude wasn't an issue that day.

You can draw your own conclusions about an airplane that, given that data, is unable to accelerate to a normal rotation speed and then stop safely on a runway of that length.

One can also draw a conclusion that an aircraft that accelerated to rotation speed and is shuddering has a some sort of serious problem that has nothing to do with possible frost on a runway.

It is highly unlikely that the rejected takeoff started 880 feet(a test pilot certification value) from the threshold. I would be willing to bet with great odds given to the other person that the initiation of stopping the takeoff was at least halfway along and possibly after getting airborne in the ground effect.

At some further point, any frost on the runway would have started having an effect.

But….we likely won’t get any further info.

Interesting to note that there was snow on the grass, cars, and roofs when I looked out the window this morning…..none on the pavement. Typical for this time of year before the ground has frozen.

[photofly]

Maybe selecting a different, better, (or even any) go/no-go point would have prevented the damage. The registered owner lives in the town adjacent to the airport, so one might imagine it was his home field, and he would have been familiar with the normal aircraft performance there.

[pelmet]

Maybe selecting a different, better, (or even any) go/no-go point would have prevented the damage. The registered owner lives in the town adjacent to the airport, so one might imagine it was his home field, and he would have been familiar with the normal aircraft performance there.

Maybe. I guess it was go at least until the shuddering started, then at some point subsequent to that it was changed to no-go. How much after the start of the shuddering....unknown. Reason for the shuddering.....perhaps hinted at by the TSB when they mentioned that conditions were conducive to frost formation. Likely cause: something other than frost on the runway.

[photofly]

If the shuddering started before reaching a well-chosen go/no-go point, then there wouldn't have been any problem stopping. If the shuddering started after the go/no-go point either he was already airborne, which apparently he wasn't, or he had continued the attempt to takeoff beyond the go/no-go point. So it's hard to envision how a go/no-go point was properly included in the takeoff procedure.

Having done so wouldn't have prevented the shuddering, but it might have prevented the accident.

[pelmet]

If the shuddering started before reaching a well-chosen go/no-go point, then there wouldn't have been any problem stopping. If the shuddering started after the go/no-go point either he was already airborne, which apparently he wasn't, or he had continued the attempt to takeoff beyond the go/no-go point. So it's hard to envision how a go/no-go point was properly included in the takeoff procedure.

Having done so wouldn't have prevented the shuddering, but it might have prevented the accident.

Best to just ensure the wings are frost-free. Then you don’t have to end up hoping you notice where some sort of guesstimated ‘no-go’ point is located.

Where would you recommend this point be located for the takeoff in question.

[pdw]

A little bit of a vague description to determine the airplane 'shuddered' due to frost on the wings.

Frost on the runway, if any, was likely a more important cause for this crash I'd say.

Note the narrative itself mentions ice but nothing about there being any “on the wings”. I guess the aircraft shuddered from the undercarriage still being on the runway while the engine suddenly misses while at full power / rotation.

[photofly]

If the shuddering started before reaching a well-chosen go/no-go point, then there wouldn't have been any problem stopping. If the shuddering started after the go/no-go point either he was already airborne, which apparently he wasn't, or he had continued the attempt to takeoff beyond the go/no-go point. So it's hard to envision how a go/no-go point was properly included in the takeoff procedure.

Having done so wouldn't have prevented the shuddering, but it might have prevented the accident.

Best to just ensure the wings are frost-free. Then you don’t have to end up hoping you notice where some sort of guesstimated ‘no-go’ point is located.

I agree about removing frost from the wings, but do you not always consider a go/no-go point as part of your takeoff briefing? It's a skill taught to all PPL students and an assessed criteria on all flight tests: "specify a GO/NO GO decision point to the examiner;"

It's there in order to prevent an occurrence just like this one.

[pelmet]

If the shuddering started before reaching a well-chosen go/no-go point, then there wouldn't have been any problem stopping. If the shuddering started after the go/no-go point either he was already airborne, which apparently he wasn't, or he had continued the attempt to takeoff beyond the go/no-go point. So it's hard to envision how a go/no-go point was properly included in the takeoff procedure.

Having done so wouldn't have prevented the shuddering, but it might have prevented the accident.

Best to just ensure the wings are frost-free. Then you don’t have to end up hoping you notice where some sort of guesstimated ‘no-go’ point is located.

I agree about removing frost from the wings, but do you not always consider a go/no-go point as part of your takeoff briefing? It's a skill taught to all PPL students and an assessed criteria on all flight tests: "specify a GO/NO GO decision point to the examiner;"

It's there in order to prevent an occurrence just like this one.

Give us detail on how and where you would have located this point for the takeoff in question. Assume no obstacles and the performance figures you have is.

[photofly]

I suppose I might have said to myself that if I’m not airborne either right after taxiway Bravo (departing 18) or past the big hangars (departing 36), depending on in which direction I was departing, I would be stopping. That would give me 1500’ to go, and 1700’ to stop.

[digits_]

Even with frost on the wings and an otherwise functioning airplane, there is no reason why it would take him longer than 900 ft to get to rotation speed. If at that point you don't rotate, there should be plenty of room to abort. Something else must have been going on.

Obviously don't fly with frost on the wings, but it's not necessarily the culprit for every accident in 'conditions conducive to ice or frost formation' either.

[pelmet]

Unfortunately, we will likely never get further info. I suspect it was just a written report to the TSB from the pilot. No mention of whether an attempt to rotate was made, which is typically what happens at rotation speed(and it was reported to have reached that speed).

No mention as to why the aircraft shuddered(which is not uncommon when an aircraft is stalling once airborne but unlikely from an aerodynamic point of view if no rotation has been attempted yet).

Delayed RTO due to attempts to get flying out of the ground effect? Who knows. A little common sense can result in plausible theories.

Or…

Perhaps that nice, smooth runway caused shuddering, or an engine malfunction, or magnetic forces from a recent solar burst.

Whatever it was, we will likely never get 100% proof. Of note, as you get experienced reading accident and incident reports, you will find that you sometimes have to read between the lines to come to a logical, likely conclusion while realizing that it is not a foolproof conclusion.

Regardless, it is the time of year for increased awareness of the effects of frost.

[AirFrame]

Carb ice could have caused a shudder. It's also the right time of year for that.

[goldeneagle]

I suppose I might have said to myself that if I’m not airborne either right after taxiway Bravo (departing 18) or past the big hangars (departing 36), depending on in which direction I was departing, I would be stopping. That would give me 1500’ to go, and 1700’ to stop.

You have an inherent assumption there that the aircraft was departing from one of the thresholds, and didn't just start it's roll from where it entered the runway.

[karmutzen]

"Frost" is just too convenient a mantra, and supports all that poster narrative. Same airplane doesn't fall out of the sky when it picks up 1/4" of ice. Most of us that fly in Canada are dealing with some frost/ice on takeoff. Adapt, there is no warm hangar, there is no deicing station, or you can just abandon the airplane there until the next summer. Clean best you can, maximize runway length, add some airspeed, reduce weight. I've seen guys take off empty, fly 15 min, then come back and load passengers with an ice-free airplane. Frost didn't down a Mooney, ignorance did.

[pelmet]

"Frost" is just too convenient a mantra, and supports all that poster narrative. Same airplane doesn't fall out of the sky when it picks up 1/4" of ice. Most of us that fly in Canada are dealing with some frost/ice on takeoff. Adapt, there is no warm hangar, there is no deicing station, or you can just abandon the airplane there until the next summer. Clean best you can, maximize runway length, add some airspeed, reduce weight. I've seen guys take off empty, fly 15 min, then come back and load passengers with an ice-free airplane. Frost didn't down a Mooney, ignorance did.

I agree that one can typically get airborne with some frost contamination with no noticeable effect. Most of us have probably scraped an aircraft with frost and there are still bits left in a variety of areas as it is really impossible to get every last bit. There seems to be a residue as well with frost. There are no doubt a multitude of variables including the actual texture frost itself(seems to be different types just like snow), the wing, the amount of frost on the wing, aircraft weight, density altitude, etc.

I have done some winter flying in Alaska in a C172 and seen some interesting frost there as well that I had not experienced before, such as tall ice crystals that was easily wiped completely away with a brush of the hand leaving a perfectly clean surface(fun to remove). One time, I arrived for a flight and there was a lot of frost and it was the regular frost that I am used to(not so fun to remove). Wing covers were used but the frost was so bad that there was some on the bottom of the wing. I did a lot of cleaning and even had a small heater but it took a long time just to clean the tail. The top of the wing and leading edge were probably 95% clean and perhaps 20% of the bottom of the wing still had frost, when added up over its entirety). I thought it through and considering that it is a high lift wing, cold out, and way below maximum weight, I took off rotating at a faster speed than normal at a slower rotation rate than normal(pretty much just let it fly off). As expected, there were no issues as I climbed out at a higher than normal speed allowing the rest of the frost to sublimate(For those ready to pounce for regulatory infraction, the FAA used to use common sense and allow aircraft in Alaska to takeoff with frost if it had been polished and maybe Canada should consider it).

Of course, this was not the first time I had done something like this. But in each case, one would want to think it through. I have flown Mooney's but they likely have a different wing that is more sensitive to contamination. If the pilot in Oliver had frost covering most of the top of the wing and left most of it in place, I wouldn't want to be on board that aircraft or most others for takeoff. Best to just get rid of most of it.

I have done the takeoff to burn off frost before the passenger arrives as well, but it was in the early evening on a light twin with a big wing(which I didn't want to scrape) just as frost was slowly starting. Did two flights to burn off the beginnings of it(and delay any more formation). But it does start up again soon after shut down of course.

"Frost" is just too convenient a mantra, and supports all that poster narrative. Same airplane doesn't fall out of the sky when it picks up 1/4" of ice.

Picking up a 1/4" of ice on the leading edge at a high airspeed is a lot different than trying to lift off at rotation speed with the top of the wing covered in frost. CatDriver has given his first hand experience on this forum of flying a DC-3 in icing conditions(handled easily) as compared to taking off with a frost covered wing(*almost crashed).

[CpnCrunch]

Perhaps the runway was frosty and the pilot held the nosewheel on the ground too long, resulting in shimmy. In that case simply rotating would have fixed it, although if you're not sure what the problem is it's probably safer to abort. Nosewheel shimmy can be quite violent when it happens.