Has anyone been dropped in guide mode when the device is levered by hand ?

I.e. WITHOUT the sling/redirect/body weight method.

I'm trying to understand if the recommendation to always back up the lowering setup has a specific justification in the manual lever case, or if it is a simplification for educational purposes (e.g. safer to say "always" than count on people understanding when a backup is vs isn't necessary).

To me, lowering using a carabiner-hand lever feels like lowering with a Grigri.  I have not (yet) seen a recommendation to back up a Grigri lower with a friction hitch.  Wondering if a guide mode device levered by a caraber has some subtle additional failure mode.

Talking about this, if it's not obvious:
 

If I understand your question correctly its because to let rope lower you have to either overcome the weight of the climbing rope, or get them unweighted from it. As long as the climbing rope is weighted it will pinch the belayer strands and not let out slack.

If you overcome the weighted rope and don't back up the climber when you undo the guided mode you've essentially created a 1:1 (corrected thanks!) pulley system around the carabiner. This sudden release of weight would be unsafe to trust purely on grip to hold.

Look at the video from OR on how to lower a follower, it takes quite a bit of force to undo the guide mode, and to lower you flip the device so that way you aren't utilizing guide mode any more.

https://youtu.be/EyxeUg7_4Kk?t=131

Using a biner as a lever to lower a second who has fully weighted a rope is nearly impossible.  Have you tried?  Focus on biner ratcheting and device redirect.  Or carry a grigri if you anticipate your second having to work on a sequence.

If you are overcoming the weight of the climber by simply pushing the carabiner up with your hand, the device locks as soon as you stop pushing - just like with a GriGri lever.

(the danger of the body-weight-redirect method in the OR video is well documented and understood, I'm not asking about that one)

chris magness wrote: Using a biner as a lever to lower a second who has fully weighted a rope is nearly impossible.  Have you tried?

Yes, several times, including people who weigh more than me.

I didn't know you could do this, but that's really handy. I don't see any likely failure modes... could be fun to experiment close to the ground and see what boneheaded things you can do while trying to lower. 2 unlikely things - maybe if you totally panic you can reflexively jerk the ATC further back and drop the climber, sorta similar to the bad panic reflex of grabbing above the rope on a grigri (but less likely). Or maybe the extra carabiner leverage could let you accidentally rotate the ATC along the axis of the loaded rope, compromising the auto-locking that way, sorta like the ATC guide failure mode when belaying 2 people at once if the ropes both pull different directions.

Hm, one thing I'm learning from the comments here is that the method is not as well known / commonly used as I thought.  That means the lack of accidents with it isn't as indicative of safety as it would be if the method were used a lot..

Jacob Wolniewicz wrote: If you overcome the weighted rope and don't back up the climber when you undo the guided mode you've essentially created a 2:1 pulley system around the carabiner much like you would have in a c-pulley crevasse rescue system.

I've used my nut tool as a lever instead of a carabiner to lower in guide mode. It seems to offer better control.
I haven't done it very often as I usually belay off my harness

Using a friction hitch backup is not specific to the lever lower in guide mode. Backups should be considered fundamental to direct anchor lowers, except if there is a obvious benefit to not use one.

Example may be, a very short lower where the fall consequence is reduced. Or a low angle lower where you may end up "fighting" the friction hitch.

There's a lot of options for direct anchor lowers, and the guide mode lever is among the worst. It should be considered an "improvised" technique and backed up. IE not your first choice if you plan to lower your partner.

Serge Smirnov wrote: Hm, one thing I'm learning from the comments here is that the method is not as well known / commonly used as I thought.  That means the lack of accidents with it isn't as indicative of safety as it would be if the method were used a lot..

I think anyone who has a pivot is likely to use this as their primary method for lowering at least short distances. I don't think there is anything particularly dangerous about it and I've never seen a serious recommendation to back it up.

This was how I was taught to lower on my reverso and I've never had any issues or sketchiness. That being said it's not often I lower in guide mode.

I find it way easiest to just throw them on a munter to lower, rather than lowering with a device.  You can easily use a friction hitch as a back-up as well.

coppolillo wrote: https://rockandice.com/climbing-accidents/climber-dropped-when-lowered-in-autoblock-mode/

According to both articles he used a sling redirect, which is a well-known cause of accidents when not backed up

chris magness wrote: Using a biner as a lever to lower a second who has fully weighted a rope is nearly impossible.  Have you tried?  Focus on biner ratcheting and device redirect.  Or carry a grigri if you anticipate your second having to work on a sequence.

This is absolutely false and I don't understand why people seek to unnecessarily make things so complicated. I've lowered people using the biner-in-the-hole method (as the manufacturers recommend) repeatedly on the Reverso and the Pivot. 

Not personally but saw someone dropped to the deck when unable to follow the crux of Bearded Cabage. This put me off guide-mode belaying for years. On reflection, I should have blamed the operator more than the device. It was Thanksgiving (2005?) and JT was a complete shitshow of incompetence: this was one of three serious or potentially serious accidents I witnessed over three days.

This is the only way I have ever lowered someone while belaying in guide mode, often with a fully weighted rope. Works great with a reverso. If I had to lower someone an entire pitch, I would probably do the whole redirect with a friction hitch, but even lowering someone like 20ft, this method works fine for me.

As with much in climbing, you need to know what you are doing, and practice enough to be confident of it. That's a real danger.

The only time I've ever been dropped, was when my partner was working out how to lower in guide mode, with me fully weighting the rope. It went from braked to nothing, instantly, and I was in free fall. I knew it might happen, it was only a very few feet, we planned on a possible fall to the deck, but it was still scarier than any fall before or since. Free fall on a weighted rope is just not like a fall with the rope to slow it. It is a complete failure of everything we count on. I won't climb multi or take a top belay with any but very experienced and very trusted partners, and yes, this partner is very trusted, both then and now.....but not yet experienced, back then.

I don't think operator error should be underestimated, in a climbing population with a lot of new climbers getting in over their heads, or worse, being ​in over their heads without realizing the danger they are in. Happens a whole lot, sadly.

Best, Helen