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[Krystal McGinty-Carter]

Its interesting that you mention the term"bingo fuel." Its a term that very common today in commercial aviation. I work as a dispatcher and do divert fuel or "bingo fuel" calculations pretty much on a daily basis. This kind of made me sit back and think how much the new generations of pilots (and their dispatchers!) take for granted.

Nowadays when we plan flights with "plan B" in mind. Not just, "fly aimlessly until we find something that resembles a runway" but we list it out, brief on and and say "If we cant get into East Jesus, we are going to fly direct to Nowheresville. It will take about this much gas. We should also carry our standard reserve, plus enough to make a few passes.   My great uncle flew in WW1 and WW2. I only met him a couple of times when I was still pretty young but my Great Grandfather recounted some of the stories that he told about flying in the days before modern fuel planning. Sure, there was fuel planning but NOT to the extent that we have today. Today we have fuel indications that tell us, right down to the drop, how much fuel we have on board. We have up to the minute weather updates, ATC resources on every corner of the earth, and ground support at our beck and call.

So I offer a modern dispatchers take on this. (Please save the questions and tomato throwing until afterwards!)

In my line of work, we are responsible for every flight from the moment it blocks out to the time it blocks in. The pilots send position reports, noting their location and fuel on board and we recalculate their fuel numbers. If the route or altitude needs to change for whatever reason, again we are hacking away at a computer to update it again.  If something happens and they cant get into their destination, we are helping our pilots find the best place to land within the scope of their fuel...be it their filed alternate or somewhere more favorable.  We are there to do these calculations so the pilot can concentrate on the vital task of flying the airplane. Amelia didnt have a "dispatcher" per se.

It has been loosely reported that Amelias "Plan B" was to head south towards the Phoenix Islands, but I have to wonder if this was a hard and fast plan or if it was something said casually. Sometimes, in our predeparture pow-wow, the Captain and I will have a discussion as to whether or not we should carry extra fuel for an alternate. Sometimes we will come to a "gentemens agreement"....usually to the tune of "Well, we TECHNICALLY arent requiring but its looking a little sketchy... buuut... we would als have to leave X many passengers behind if we carry an alternate. So lets do this: If things start to go tango uniform enroute, we'll drop into X station."  Something tells me her plan B, if she had one, probably went something like that.   

Ive heard all of the fuel numbers and all I can gather is that she was carrying fuel to get her to her destination plus reserve. It would seem that if she intended to use the Phoenix group as her alternate she would have ensured that she would have enough to GET to the Phoenix group....meaning that when she was filling her airplane, she would have had to have, at the very least,  allotted X amount of gas to get there.  Whats the point of having a "plan B" if youre just going to run out of fuel halfway there and end up in the drink?  If this were the case, one would think we would see more documentation about it.   I dont think Amelia ever believed that she wouldnt reach Howland.  We have personal recounts that she was particularly arrogant in that sense. I also believed that she suffered from a debilitating condition that I see in many of my crews who are on the last leg of a 4 day pairing faced with unexpected bad weather or some other fast arising circumstance.....a serious case of "GetHome-itis." We have pilots who could fly a bathtub, but something about suddenly getting put into unexpected airborne holding on their "go-home" leg, makes some pilots want to push it even if the situation is hopeless. For example, an airport fogs in at 1 am and now its below mins. Its highly unlikely its going to improve in the 20 minutes of fuel you have to hold with before you HAVE to divert....but pilots with GetHome-itis will hold down to the last minutes and often times end up cutting into their reserve getting to their alternate. Mind you, I was a commuter for 6 years and have suffered from this condition as well.  Its like having a monkey on your back. All you want is to walk in your front door, grab a beer (or pop or milk or whatever) from your icebox and be HOME.

 Moving on. I dont think she specifically had Gardner in mind when she took off for Howland.  Nor did Noonan. In her mind, there was no other option but Howland. I just dont see a preplanned "bingo fuel.".

What I DO see is that she had a very experienced navigator.  While he may not have known the name of the island, he certainly had the most up-to-date charts attainable for the time and surely would have started sniffing out somewhere ANYWHERE they could reach. He starts doing the math. While Amelia is still holding out hope in a deteriorating situation, perhaps her navigator was plotting out distances.  At some point, perhaps he finally convinced her that the circling thing was doing nothing but wasting gas, time and energy. Showed her the calculations and helped her work out the fuel to determine if it was possible.   I dont think it was a " holding down to divert fuel" in this case rather more of an "Airport closed on final....find a peice of pavement (or in this case, coral) and land on it." 

Maybe Noonan took on the role of an early form of dispatch. 

[Nathan Leaf]

Great post Krystal.

I am informed by World War 2 military aviation, especially carrier aviation, and so use the term "bingo fuel" accordingly.  While I believe you are absolutely correct that fuel measurement and planning was not as exact and extensive then as it is today, I can assure you that for carrier operations, it was the primary consideration in planning flight operations.  One can only appreciate the agonizing decision Admiral Spruance faced after locating the Japanese carriers at Midway, recognizing that launching his planes at maximum fuel range (for normal cruising flight) meant ordering the deaths of many of his pilots and gunners, and the losses of many, if not all, of his extremely valuable planes simply due to limited fuel range.

Even land-based aircraft learned this lesson early in the war ... Japanese fighter escorts in the long flight from Rabaul to Guadalcanal learned how critical fuel conservation was to their survival, and their combat tactics evolved accordingly.  The American ground-based aircraft at Guadalacanal learned these same lessons towards the end of the campaign, as the Allies established their toehold in the Solomons.

As neither Earhart nor Noonan was a military aviator and were making their flight prior to the valuable aviation lessons learned in World War 2, it is unlikely that either of them used the term "bingo fuel" nor even incorporated it in their psychologies as a rigorously urgent concept to the degree a naval aviator might.  I do agree Earhart was arrogant to some degree, and I agree she fully believed she would find Howland.  I doubt Earhart participated in Noonan's Plan B beyond sharing fuel calculations and a casual discussion of the "what ifs".

But I certainly believe Noonan had a Plan B.

Noonan had the experience of navigating across the Pacific for PanAm, so he knew and understood the unique challenges of flight in that region.  He was also an officer in the Merchant Marine during World War I with the threat of u-boat torpedo attacks ever present (he was supposed to be on one boat, S/S Cairnhill, which was torpedoed and sank with all hands lost, as well as Noonan's passport and personal belongings!).  I do not believe Noonan shared Earhart's posited arrogance when it came to contingencies over vast stretches of ocean.

And so while he might not have known Gardner by name, I believe he knew Baker by name, and knew Baker was to the SSE of Howland, and considered it as a possible 'locator' prior to the flight.  I believe Noonan *must* have considered the possibility of failing to find Howland.  And in so doing, he would have recognized that there were two alternatives if they failed to find Howland after cruising the LOP for a period of time: 

1) doubling back to the WSW towards Beru Island;
2) continuing on the LOP to the SSE in hopes of finding either Howland or Baker. 

Choosing between those alternatives would be determined by the fuel consideration ... Beru was certainly near (if not beyond) the extreme end of their fuel range given a search period in the Howland vicinity.  Alternative #2 offers the advantage of including 2 possible islands to spot well within fuel range ...  this is the critical contingency factor in my view. 

So then Noonan considers the next "what-if" ... what if we don't see Baker?  He continues the SSE course line to ... the Phoenix Islands. He reviews his fuel calculation, and draws an 'X' near Gardner.  Between Baker and that 'X', he sees possible markers in the form of coral atolls on his chart, and then MacKean.  Not inviting prospects, but better than a ditch at sea near Howland.  He calculates fuel again to determine when they would need to depart the Howland area to reach 'X'.  That is Plan B ... the worst case scenario, with the "bingo fuel" time established only in Noonan's mind as a dark and remote consideration. "If we don't see Howland, surely we'll see Baker," he says to himself in a nervous, self-comforting tone.

So although I don't think Earhart had Gardner in mind when they took off for Howland, I think Noonan certainly had Baker in mind, and thus had Gardner in mind to the extent that the Phoenix Islands represented, literally, the end of the line on the 157 heading. 

Whether he shared specifics of Plan B beyond Baker with Earhart prior to their flight is endlessly debatable, but I think once their search time for Howland began to approach the time Noonan had established as "bingo", he would have felt compelled to share the details of the considerations that went in to Plan B with her.  And if that is the way it happened, I can only imagine Amelia's change in mindset as that discussion progressed.

This is not to say I do not preclude the possibility that your version of events, i.e. Noonan as in-flight "dispatch" once panic begins to set in near Howland, is the correct one.  It's just difficult for me to accept that a Navigator as experienced as Noonan would fail to have a Plan B, and by definition, the primary consideration for any Plan B in aviation is fuel.

[Krystal McGinty-Carter]

Good point.

Could you elaborate on Noonan having a calculated "bingo" in mind?  Are we speculating that he would have been monitoring the fuel in flight or that he took their current fuel situation and came up with his own?  While Im sure Noonan was a highly skilled navigator, I have to wonder how much training he had in fuel planning.   He had limited flight training. It seems that Earhart would have had a much better understanding of how her airplane burned fuel so wouldnt it, in theory, be Earhart who calculated the bingo?  Fred may have had the plan B in his head, but it would have been more likely that Earhart came up with the "divert fuel."

"Hey Amelia, look at this. If we fly south on the LOP, we should see Baker. Do you think we have the gas for it?"
"Im pretty sure we do."

.............

"Ok, Freddie. We should have seen Baker by now. Got any other ideas?"
"Well, if we keep flying south we should hit the Phoenix group. Lots of places to land there."
"Its going to be pushing it but I think we can do it."

............

"Hey look! An Island!



*Cue dramatic music as she comes in for a landing*


-Krystal "Dispatch Betty" McGinty

[Nathan Leaf]

My speculation is that he calculated the "bingo" before they ever departed Lae, with the information on the Electra's fuel consumption they had accumulated to date.  Earhart, as a pilot, may have had a better understanding of how the Electra burned fuel, but I doubt Noonan neglected this critical area of flight planning, and I presume he consulted her regularly both on the ground and in flight to tap her evolving knowledge.   That knowledge would be an important part of the Plan B process that an experienced, disciplined navigator employed prior to every leg of every flight.

I do not speculate as to how they monitored or calculated fuel in-flight on that leg to Howland ... my hunch is that Amelia's posited arrogance biased her to persisting in finding Howland even if that meant going beyond a pre-calculated "bingo" by a few or several minutes, while Noonan's discipline as a navigator biased him to adhering strictly to the Plan B that I believe he devised before they departed Lae.  If conflict emerged here as the search for Howland became increasingly fruitless and fuel was running ever lower, it is certainly possible that they would do whatever possible to confirm their existing fuel levels, insofar as this is even possible to achieve to a high degree of confidence (in-dash fuel gauges were known to be notoriously inaccurate) to stretch their time in the Howland vicinity as long as possible.

[Krystal McGinty-Carter]

My question is not so much "Did Fred have a backup plan" but more "Did he have a hand in the fuel planning for said backup?"    I don't doubt he had some kind of "contingency plan" but was he going over the fuel at regular intervals throughout the flight and making those calculations himself, or was Amelia doing it? We they working it out together. Was Noonan peering over her shoulder and secretly making plans to tie her up and take over the plane if she didn't listen to him about bugging out?    How much would he have known about how to do those calculations?  We see some writing about his time flying with Pan Am but was he solely responsible for navigation or did he perform other pilot-not-flying duties such as monitoring fuel consumption? 

Maybe he mentioned his backup plan to her on the ground and THAT is where the rumors about the Phoenix Group alternate came up.  And if he did mention it, do you think she listened?

[Nathan Leaf]

I think the answer to your question is yes, he had a role in "fuel planning".   After all, you cannot execute a contingency plan if you do not have the available fuel.  And the contingency plan most certainly required input from the navigator.  So it becomes a circular part of the process with just two people on board the aircraft.

Whether or not you believe Gene Vidal's hearsay about Amelia's plan in case they couldn't find Howland, specifically that they would fly a reciprocal to the Gilberts, they must have discussed the possibility of not finding Howland in the flight planning stages before departing Oakland.  If not then, they must have discussed it at some point between Oakland and the departure from Lae.  How could they not have discussed the contingencies around the singularly most difficult navigational challenge in the history of human aviation to that point?

If Fred heard Amelia say, "in that case, we'll turn around and fly back to the Gilberts", he very likely took out his charts, plotted that course, and performed some calculations.  The question underpinning those calculations is:  do we have the fuel for this? 

That's not just a simple question for an experienced navigator, it is a particularly burning question, because this leg of the around-the-world flight stands out from all the rest.  Beyond the simple hazards of flying and the unpredictability of weather, this leg is the only one without a suitable alternative to the primary objective for landing the plane even if conditions en route are perfect.

To me, from the moment that question entered his mind, it matters not when and where he discussed it with Amelia or anyone else involved in the flight planning for that matter.  It was a critical consideration, one he could not have ignored as the flight's navigator.

Maybe he kept the question to himself initially and simply inserted himself into an active role monitoring and calculating the Electra's fuel consumption as the flight proceeded east from Oakland, then broached the subject of Plan B fuel considerations with Amelia in Lae.

Or maybe he pulled her aside during the planning phase in May as the aircraft was being repaired, asked her to show him her calculations, and then threw the Baker/Phoenix/157 line out as an alternative to a Gilberts reciprocal.

I don't know.  But the uniqueness of that leg of the trip made fuel consumption the primary consideration in navigating for Plan B. 

"Amelia, if the Gilberts is your Plan B, we should consider flying along the LOP to the SSE instead.  If we find Baker, we will know how to return precisely to Howland and have plenty of fuel to find it and land there with a narrowed search area.  But if we don't find Baker as we fly SSE, we will likely encounter one of these islands [MacKean and/or Gardner] in the Phoenix Group, which offer similar prospects for ending our flight as the Gilberts ... undesirable, to say the least.  Using the only other identifiable landmark, Baker Island, in the vicinity of Howland in our Plan B is extremely prudent given the fuel considerations we face."

How could she not listen to that?   

[Krystal McGinty-Carter]

How could she not listen to that?   

She didn't listen to the radio experts. 

[Nathan Leaf]

How could she not listen to that?   

She didn't listen to the radio experts. 

True.  But the radio experts weren't on board with skin in the game, either.

[Krystal McGinty-Carter]

You have to wonder what was going through his head when the radio became hopeless.

There is so little published about Noonan's thoughts through this entire ordeal. Or perhaps it just seems that way because of the overwhelming number of Earharts documents that have been published.  His letters home were simple, to the point, and a little dry. It appears he didn't discuss much about the trip, at least in the technical sense.  Earharts letters could be overly descriptive and full of emotion and she wasn't shy about sharing the details.  You have to wonder if he kept any kind of journal or log that would have revealed his true feelings, thoughts, and opinions of the trip, including any misgivings. I think by the time they departed for Howland, Earhart was just so ready to get the H back to California that she may have been overlooking some thing.  Noonan seems like he was probably the quiet voice of reason. It may have gone in one ear and out the other but I imagine he was used to that. So perhaps he kept that Plan B in the back pocket just in case. He knew how much fuel they had on board and perhaps roughly how much they were supposed to have when they landed and kept that in mind. He knew that if they got lost, she would have no choice but to pay attention.

[C.W. Herndon]

Its interesting that you mention the term"bingo fuel." Its a term that very common today in commercial aviation. I work as a dispatcher and do divert fuel or "bingo fuel" calculations pretty much on a daily basis.

In all of my years as both a military and civilian pilot, I never heard the term "bingo fuel" used anywhere except during combat operations of the military. Here is a link to what the U.S. Federal Aviation Administration has to say about the use of the term.

[Krystal McGinty-Carter]

Oh I understand where the term came from.  This is the third airline for which Ive had the pleasure of dispatching.  We have used the phraseology "bingo fuel"  in all of them.

I dont particularly care for it, personally. In my opinion its too vague. You will never hear me use the phrase "bingo fuel, x.x" in any ACARS or ARINC communication. I word it as "Divert to KABC at x.x lbs of fuel." When Im dealing with flights in the air, I am direct and to the point. "At THIS amount of fuel, GO HERE."

[Nathan Leaf]

I did not introduce the slang "bingo fuel" in this thread to suggest FN/AE used that terminology, nor to suggest that it was common terminology at the time amongst anyone other than U.S. carrier pilots, nor to suggest that we use it here as standard lexicon when discussing contingency planning for the final leg of this tragic flight.

I used it because it is a very convenient (and specific) term, even if just military aviator slang, to use to explain a different conceptual approach to Noonan's possible contingency planning than that put forth by the LaPook hypothesis (i.e. box search Howland) or the Tighar hypothesis (NNW on LOP, then SSE on LOP to Howland), which in fact allows for either (or even both) of those scenarios by starting from the end point: running out of fuel.

If the contingency originally considered was a ditch at Beru Island (closest of the Gilberts) per Gene Vidal's hearsay evidence of Amelia's comments, then Noonan was compelled to consider alternatives because the corresponding equation, max fuel range = ditch at Beru + reaching Howland vicinity with no search time, was not very inviting.

Alternative A = LaPook.  Box search for Howland until fuel runs out
Alternative B = Tighar.  Reach LOP, then NNW for , then SSE until fuel runs out

The "bingo fuel" concept simply constructs the contingency in reverse.  Differences in assumptions around max fuel range among the various theorists notwithstanding, what is the most distant landfall achieveable that allows for at least some incremental search time in the Howland vicinity (as opposed to the zero search option offered by the Gilberts)?  Manra, in the Phoenix Islands, offers only a slightly better prospect than Beru.  The Gardner-Canton line, on the other hand, offers some time on station near Howland.  Gardner's a touch closer than Canton.  And Gardner has the advantage of being very close to the Howland-Baker line, with McKean and Winslow Reef also in the vicinity as possible "catcher's mitt" markers. 

I draw my "X" at Gardner.  "Bingo fuel" is the time to depart the Howland vicinity on a heading that approximates the LOP to the SSE to burn my last drops of fuel upon reaching "X".   Whether the time between arrival to the Howland vicinity and "bingo fuel" is spent in a box search or cruising the LOP to the NNW and back again, or both, is irrelevant.  The point of the "bingo fuel" exercise is to demonstrate that this contingency allows for the same possible outcome as an immediate return to the Gilberts but with three distinct advantages:

1) Time to search in the Howland vicinity.
2) Potential to spot Baker and thus navigate to Howland from Baker.
3) Potential to spot Winslow Reef, McKean or Gardner itself en route to Gardner.

I fully apprciate the criticisms of this approach. i.e. "you can't navigate from an unknown location..." and "a fuel calculation to reach X from Howland requires that you be at Howland...", and also of course the possibility that they didn't have enough fuel to reach Gardner in the first place.  But if you're lost, something has gone wrong, and your contingency plan goes in to effect.  The margin for error en route to Howland is greater to the North-South than it is for East-West, so if you missed the Howland-Baker "catcher's mitt" on either side (or right in between), flying SSE to 'X' after "bingo" is reached searching (whether box search or otherwise) offers the highest probability solution to the predicament.

(Apologies for duplicating many of the discussion points from the other navigation threads here ... I have read them all, including Gary's posts on his site, but wanted to offer my perspective).

[JNev]

The LOP does not seem to have been of 'Baker and the Phoenix group' but rather a logical device for finding Howland.  We've heard a lot about search patterns - boxes and offsets, etc., but not one shred of radio traffic supports a 'box', but 'LOP 157-337' rings clear as a bell, and we know what it would relate to: it would have passed right through Howland on any reasonable plot Noonan would have been working on.

That Gardner may have been found in lieu of Howland suggests to me that an accident of navigation happened along the way - some will howl, but my belief is that was a likely outcome and because the flight somehow got tragically further south on it's approach to the LOP / what was thought to be Howland, than intended.  They had to fly all that night with a lot of blindness if I understand weather and what Earhart had to say; I don't know that they had any great means of tracking for drift, either.  In those conditions, that kind of navigation - dead reckoning, can easily put you off several percent - maybe 10 or 15% if winds are bad enough.  Maybe Noonan thought he had that pegged and over-compensated, not realizing an error; maybe he had no way of knowing... maybe, maybe, maybe - point being, 'unkowns'.  It is not hard to think of the flight emerging at what would be an extension of the LOP (or what they thought was on it) many miles south (I've left off the specific arguments of winds, etc. here for now).

"On the line 157 - 337" at the end of known things about Earhart doesn't sound much like "turning back to the Gilberts", or "about to start a box search" to me - it sounds much more like "we've flown up and down the line and can't see it", if I had to guess.

So what next?

Noonan had to have known something of fuel state - it is fundamental to any notion of navigation.  As such, he'd of known that the Gilberts were a bridge too far, in all likelihood.  I don't buy that he was ignorant of the Phoenix group, and while perhaps not equipped with specifics, I doubt he'd of missed that at least there was scattered land down there within 300 or so miles - as opposed to flying off to the NNW.  Not much of a catcher's mitt, but better than tying to make it to Siberia - and logically may have thought they'd hit Howland yet, just further south than thought.

But what of Earhart's own statement about turning back as a contingency?  I suspect Noonan let Earhart go on as she would, but did his own thinking about the details.  As Krystal pointed out, he may have known she'd listen if she had to - but probably not so much before she had to.  I tend to suspect an eventual Phoenix-direction was therefore a) accidental to some extent, and b) realized by Noonan as a safer error than some others -

And the rest would be pure luck, if they hit Gardner like many of us think they did.  It would not be hard to spot from some distance, as opposed to a bitty island like Howland.  Last we knew, they were on a 'track' (direction not known, admittedly) that could get them there, too.

That leaves some variables in some of our minds - like has been suggested, Noonan might have gotten a moon shot in the daylight and realized he was too far south.  I've argued that - and maybe he did - and maybe it came too late: fuel might have overruled - go for broke, we'll never hit Howland but may just find a Phoenix group island.

Great mystery, isn't it?

[Steve Van Slyke]

New member, first-time post (marine celestial navigator).  After reading Long, Gillespie and King, here's my present assessment.

Since AE and FN never spotted Howland, nor did the Itasca spot them, it must be assumed that either Noonan's advanced sun sight LOP or his DR (or a combination) were significantly in error.   If the assumed advanced 157-337 LOP was good, this would mean that the DR was off by probably 40 miles or more (standard maximum DR error of 10% for air navigation would have been 222 NM). Given how far he was off on the Dakar landfall after crossing the Atlantic, this seems entirely possible.

If the assumed advanced LOP was not good (+/- 10nm errors not uncommon, I am told, in aviation celestial) then, the DR may have been relatively good in terms of course, but they would have turned short or long of the line passing through Howland.  Most likely they would have turned short since the prevailing winds were against them and stronger than they apparently assumed.

Thus in the former case they may have been on (or close to) the line passing through Howland, but because of DR errors have been so far to the south of their intended track that when they ultimately turned on the line to search for Howland they were already south of Baker, which would explain why they saw neither island.  In the second case (errors in the advanced LOP) they might have turned south 20 or more miles short of the line passing through Howland and Baker even though their track toward Howland was good.  Without RDF bearings they could not know.

[JNev]

Welcome, Steve, great post.

As a marine celestial navigator you are well-qualified of course.  What you have shared is very much what I have believed may have happened in my less qualified view. 

Your point about a combination of errors, that is with regard to the line of position and DR effort, makes a great deal of sense to me.  Had the flight turned onto what was believed to be the line of position too soon, Noonan may have set the flight up to find Gardner quite unwittingly.  Secondly, if too far south as you describe, Howland and Baker could easily have been missed during any excursion to the north to find Howland along the believed line of position.  This too would put the flight in a better place to run across Gardner during further flight southward. 

I have seen many arguments both ways, but do believe that because the Phoenix group does offer some better chance of landfall than would further travel toward the Northwest, that the final exploratory leg along the line of position most likely would have been to the southeast.

My suspicion is that The flight simply and accidentally found itself within site of Gardner island within an hour or so of Earhart's last confirmed call.  I believe subsequent calls that may have been made simply were not heard, tragically, due to some problem with her day time frequency.

Of course this view is disputed by some.  One argument against it is "you can't navigate to Gardner if you don't kmow where you are in the first place" - and I agree, hence the navigational accident as described.  Another is that the Phoenix group is so scattered as to be useless as a 'catcher's mitt' - and I agree somewhat as I believe that the idea may have been secondary: some scattered lands are better than none, so why not use that at least slim possibility in one's favor when calculating the final direction for land or bust?  It should beat knowing that no lands will be found if one has erred to the north.

What amazes me is how certain some are as to how wrong this all has to be, and that the flight could only have ended in the open sea.  Maybe - but I have severe doubts about that for the same reason Friedell (Capt of the USS Colorado) did - a land plane navigitor should be expected to think in terms of finding alternate land, not fuel exhaustion over open water.

I suppose like so many things about this mystery, however, many are guided more by their particular fixations than by points such as you have made so well.  Thanks for sharing such a well qualified view of the Earhart-Noonan navigational conundrum.