world headquarters in new york, this is "nbc nightly news" with lester holt. good evening. now more than three weeks in, and with a battery life on those critical black boxes now measured in days, the search for that malaysia airlines 777 is only intensifying tonight. as the sun breaks on what is now a monday morning in australia, a second u.s. navy plane is poised to join the international hunt for the wreckage of flight 370. this, after they took advantage of better flying weather today. families publicly directed their anger at malaysian government officials, a determined group of aviators pressed on over the indian ocean in a risky top-wave search that today i.d.'d more potential clues to this tragic mystery. our bill kneale was on board. >> reporter: early morning and hopes rise again with the search planes. they fly 1,000 miles and then begin another long day of scouring the ocean for anything. it's week four, and so far, not a single object they've seen can be linked to the missing plane. all eyes are on the ocean and the visibility is clear. but one thing that's also clear is how immense this search area is. bigger than most states. suddenly, they spot something. the plane turns sharply and they load up smoke flares, firing them to mark the location. but it's a tree, not wreckage. up go the binoculars again. >> we owe it, i guess, to the families, anything that we can provide some answers for them, we want to, and we will. >> reporter: soon, another sighting. more promising. it's big and looks like metal. they sweep past it, over and over. well, this is what they saw from 500 feet. now the colors of the malaysian plane are red, blue, white and gray. so you can see how that would have attracted attention, but it is, in fact, a fishing net. then another sighting. four objects, maybe more. >> they were orange in nature, between two to three meters in length. we dropped a gps locater buoy in the area. >> reporter: what they see, ships will try to pick up and examine tomorrow. after 11 hours on this, the most intensive day of searching, rescue 103 returns, their piece of the puzzle done. but the mystery of flight 370 remains unsolved. bill kneale, nbc news, perth, australia. i'm katy tur in kuala lumpur. frustrated that they weren't getting enough information in beijing, dozens of chinese family members of passengers on mh-370 flew to malaysia on sunday and made their presence known immediately, holding their own news conference. clutching banners and chanting, "we want the evidence. we want our relatives," demanding answers the malaysian government says they just don't have. we want them to apologize for giving out confusing information in the past week which caused the delay in the search and rescue effort, says one man. >> the first thing we would want is to get our family back. that's the most important thing. >> reporter: 23 days since mh-370 went missing and many of those whose loved ones are now lost refuse to accept the malaysian officials' version of events, doubting the plane was even in the indian ocean. six days ago, the prime minister said it was beyond any reasonable doubt that the plane was lost and anyone on board survived. on saturday, these words from the malaysian transportation minister. >> hope against hope. please, we will continue to find survivors. >> reporter: confusion that is only fueling their suspicion that the malaysian government either severely mishandled the search or is not being entirely forthcoming. and those chinese families will be going to a prayer vigil in a few hours. so far, the malaysian government hasn't responded to them publicly. but, lester, they haven't had their daily news conference, their daily news updates, since friday. >> katy tur for us in kuala lumpur, thank you. still on edge tonight, as more than 150 aftershocks have rocked the region on the heels of that 1.5-magnitude earthquake friday night. rehema ellis has more for us. >> reporter: when the earth shakes like this, as it has twice in the last 14 days in southern california, it rattles nerves. >> like, i still can't like breathe correctly because i'm scared it's going to happen again. >> reporter: customers ran for cover at this ice cream parlor. you can see the furniture sway in this 5-year-old's bedroom. friday's 5.1-magnitude quake was centered in la habra, just outside los angeles. since then, more than 150 aftershocks ranging from 1.0 to 4.1 have hit the area. at least half a dozen houses have been red tagged for further inspection. are you getting calls from people wondering should they stay in their houses? >> we're doing a lot of calming and educating the public and telling them what to expect. make sure they're ready to shut the gas off if they have to. make sure that all their children know the exit and where to meet. >> reporter: southern california gas continues to respond to 1,000 calls about gas leaks, while power has just been restored to nearly 1,000 customers. this couple from fullerton sustaining serious damage to their home. the fire department told them their chimney could come down in the next quake. do you think about when that could happen? >> every time we feel a tremor. >> you don't know if that's -- >> yeah, you don't know if that's the one. >> reporter: but could there be a big one in store for california in the near future? lucy jones from the u.s. geological survey said it's highly unlikely that friday's quake is a foreshock to a larger seismic event. >> by the time we get another -- into the weekend, the probability is essentially gone. >> reporter: but a 7.5 quake on the same fault line could hit the densest neighborhoods in los angeles and prove deadly. >> people are very nervous out there right now. we haven't had an earthquake like this in quite some time. >> reporter: rehema ellis, nbc news, los angeles. in washington state, eight days now since one of the worst mudslides in u.s. history, and the work of finding the missing and the remnants of their lives goes on tonight in treacherous conditions. meantime, the number of those thought to be missing has actually been scaled back now, on a day when the victims were honored. nbc's miguel almaguer is there again for us tonight. miguel? >> reporter: lester, the number of missing dropped from 90 to 30. the official death toll is 18. though they've found another body, yet to be identified. the rescue mission is under way as the heartache sets in. in a community where faith has been tested -- >> this week is hard to put into words. >> reporter: -- tonight, there is comfort no one here is alone. it seems most of oso has reached out to natasha houstis. >> people brought brand new clothes. >> reporter: the 26-year-old lost her mother, christina, her daughter, sonoa, and everything she owned. >> people see a mudslide and they see all the aerial photographs, but they don't see the people who lived in there. >> reporter: memories and pictures pulled from the mud are all natasha has left. keepsakes like her baby's bunny. but tonight, she's worried about her best friend, amanda, and her son, baby duke. >> our houses were about 70 feet apart maybe. >> reporter: they are still in the hospital. >> she can't even sleep at night because she has so many memories of what just happened. how do you get that out of your mind? >> reporter: now eight days after the slide, many of the survivors want answers. why didn't everyone know this hillside was deemed unsafe? >> it was a known hazard. the timing of when something like that would fail in the future is obviously very difficult to establish. but the idea that that was actually a dangerous slope was known. >> reporter: washington's governor, jay inslee. >> we will get to the bottom of all those questions. it will take a very extensive geological review. but today, look, we got to focus on this rescue and recovery. >> reporter: with 620 people involved in the rescue, exhaustion has set in. >> takes you ten minutes just to go probably five feet. >> reporter: search dogs ordered on a two-day break before they can return. in oso, everyone wants to help. and in this small town, tonight, everyone is still hurting. with dozens still missing, today the governor insists this is a rescue mission not just a recovery. tonight search teams will enter day ten. >> miguel, thank you. a memo released by congressional investigators reportedly shows that federal safety officials declined to launch a formal investigation of the problem more than six years ago, even after being presented about problems and complaints and reports of crashes. on tuesday, a house subcommittee will open a hearing on the ignition problem and recall of millions of cars. gm's new chief executive is scheduled to testify. the future of ukraine and competing visions for that country was the subject of an urgent meeting in paris tonight between secretary of state john kerry and his russian counterpart. nbc's kristen welker is following it for us from the white house tonight. kristen? >> there seem to be an agreement toe keep talking. kerry said he and sergei lavrov talked about ways to deescalate tensions. and he raised concerns about the russian troop build-up along the ukraine border, which he says has caused a climate of fear and intimidation, but russia didn't say it would pull back. kerry wants to see free and fair elections as well as rights for minorities. he emphasized it is ultimately up to the ukrainians to decide the road ahead. now, tensions have been mounting since russia annexed crimea earlier this month with the u.s. concerned russia wants to enter other areas of ukraine. today, defense secretary chuck hagel ordered nato's top commander to head back to headquarters in europe, saying a lack of transparency on the part of russia when it comes to their troops. lester? >> kristen welker, thank you. tomorrow is the official day for enrolling in a healthcare plan from the affordable health care act. more than 6 million people have enrolled since the program was launched six months ago. despite the disastrous rollout of the government's website.,. despite the disastrous rollout of the government's websit . despite the disastrous rollout of the government's websit despite the disastrous rollout of the government's websitdespie the disastrous rollout of the government's websitfgovr websitalgovernment's websit government's website. nbc's peter alexander is taking a look at one state where volunteers are making that final push. >> reporter: in huntsville, alabama, 24-year-old devon cross is part of a grassroots campaign. >> find out the most affordable coverage for you. sound good? >> sounds good. >> reporter: one of 600 student volunteers crisscrossing the state to enroll the uninsured here before the march 31st deadline. for people upset about obamacare, especially in a state like alabama, what do you say to them? >> do you want to help? do you want to be insured? >> reporter: taking their message to barbershops and free health clinics like this one that can barely keep up with the number of uninsured adults who need care. >> healthcare is not a political issue. fundamentally, it's about protecting your family. >> reporter: new yorker david liss left a dream job as a banker in london to create bama. >> this is about healthcare in your community and there's nothing more american than access to care. >> reporter: liss says his volunteers have signed up more than 3,000 people. alabama isn't exactly the easiest place to sell anything obama. as one of the most conservative states, alabama has some of the most vocal opponents, including governor robert bentley. >> everything in the patient protection and affordable care act is everything but affordable. >> reporter: with limited resources, trying to accomplish on a local level what the administration is spending $52 million this year trying to do nationally. >> sign up now. you never know when you might take a hit. >> reporter: let me see the office. liss has been working out of his used honda since december, packing up 1,000 miles a week. >> i keep my bag under here, more flyers. water bottles. my toiletries. can't leave home without those. >> reporter: you're living out of this place. a personal campaign going down to the wire in the midst of a heated national debate. peter alexander, nbc news, huntsville, alabama. when nightly news continues on this sunday, the grueling and emotional work of first responders. dr. nancy snyderman looks at the impact on them. and later, a study raises new health concerns for women about consuming diet drinks. for eight days now, we've seen how difficult the recovery has been in washington state after that devastating mudslide, not only for the dozens of families involved, but the rescuers taking part in the effort. we asked our chief medical editor, dr. nancy snyderman, to take a look at the impact of this kind of work on the first responders. >> reporter: goat farmers jeff and jan mcclelland have been volunteer firefightersn washington the last five years. but nothing prepared them for what they faced this past week. >> when we got to this particular incident, you couldn't even fathom what had happened. >> reporter: one of the worst landslides in u.s. history. >> people can be gone so fast. just tell the people that you love that you love them and hold them close. >> reporter: first responders like the mcclellans risk their lives to try to save others and experts say their wounds also run deep. >> in some ways your whole system is overwhelmed by the stress. you can feel helpless that you can't do enough to save people. >> reporter: the responders put their own needs aside when disaster strikes, people like paramedic tony mccarty, who we met last may in moore, oklahoma, when an ef-5 tornado cut through his community, killing 25 people. he was one of the first on the scene. >> there is nothing good to say about holding a lifeless child in your hands. you hurt for the family. >> this is the side of first responders that people don't get to see. >> reporter: but when they save lives, it's a reminder why they make the sacrifice. >> one, two, three. >> reporter: when a devastating earthquake struck haiti four years ago, killing more than 316,000 people, the los angeles county fire department answered a call for help. >> when you pull somebody out alive, regardless of the circumstances, they're all tough, but it's remarkable. >> as difficult as all these things are, the reality is that there is a part of some people that go through this that develop new meaning in their life. >> reporter: back in washington, jeff and jan mcclellan continue to help in the search, masking their pain. >> you don't take the time to deal with it right now, 'cause we -- i feel like we don't have time to deal with it right now. >> reporter: when so many have yet to be found. >> we keep on going, because we're going to bring closure to families. >> reporter: still searching for the missing and the will to stay strong. dr. nancy snyderman, nbc news. we're back in a moment with a possible link between diet drinks and heart disease in women. we're back with health news and a study that came out this weekend suggesting a correlation between health disease and consuming diet drinks. the research was presented at the research was presented at a meeting of the american college of cardiology in washington. we get more tonight from kristen dahlgren. >> for many women, it's a daily staple. >> i drink it because it has less calories and i'm always watching my weight. >> reporter: a new study suggests that older women who drink more diet drinks may have a higher risk of heart disease. >> women who consume two or more diet drinks had higher rates of cardiovascular events. >> reporter: the women's health initiative study looks at 60,000 postmenopausal women over a nine-year span. the women who consumed two or more diet drinks per day were 30% more likely to experience a cardiovascular event and 50% more likely to die from related heart disease than women who never or rarely drank diet drinks. researchers caution it may not be a direct cause and effect. the women may be choosing diet drinks to compensate for other unhealthy habits. the researchers did note that the women drinking more diet drinks often did have more risk factors. >> the higher proportion of women with a history of diabetes, a higher proportion of women with the history of high blood pressure. they also, on average, consumed higher calories. >> reporter: in a statement, the american beverage association says because of other factors, it is impossible to attribute their cardiovascular health issues to their diet beverage intake. but for researchers looking into the science of heart disease, it is at least cracking the surface. >> it raises a challenge to the scientific community to look at this further and hopefully in the near future, we will have a definitive answer to this question. >> reporter: a question that has many wondering whether their favorite drink could have bitter consequences. kristen dahlgren, nbc news, new york. up next, another milestone, marking half a century of trying to come up with the right question. finally tonight, it was on this day 50 years ago that a game show phenomena was born right here at 30 rock. after all that time, "jeopardy!" still draws millions each night, trying to guess the question to the answer. here is nbc's erica hill. >> let's play "jeopardy!". >> reporter: and that's how it all began back in march of 1964, as art fleming introduced viewers to what would become the most popular quiz show of all time. >> there had not been any trivia quiz shows on since the 1950s because of the quiz show scandal, but merv griffin brought it back with "jeopardy!" >> reporter: creator merv griffin credits his wife with the idea, give the answer and have the contestants guess the question. >> what are cigars? >> cigars are right, yes. >> reporter: art fleming aired the original "jeopardy!" which taped right here in this studio at rockefeller center. >> that is the award they gave me for being grand champion. >> reporter: this retired navy technician, who first appeared on the show in 1965, went on to become the all-time leading champion of the fleming era. what was it like when you got here, to be a contestant on "jeopardy!"? was it nerve-racking? >> you had a degree of nervousness. if you're going to be on "jeopardy!" you have to be a little bit tense. you have to be a little bit nervous, because if you're loose, you lose. and you get beaten by the button. >> reporter: how much money did you walk away with? >> $11,110. >> reporter: from fleming to trebek, the show has produced its share of headlines over the past 50 years. in 2000, a record store clerk went on to win the most money in "jeopardy!" history. >> about $3.4 million. >> reporter: the record for longest winning streak goes to ken jennings, helped by a change in the rules. >> up until 2003, a champion could only win for five days. now it's unlimited. >> reporter: brad rutter admits there is a friendly rivalry between he and jennings, but neither was a match for ibm supercomputer, watson. >> what is arabic? >> ken and i looked at each other and said this must be what it's like to play against us. >> reporter: no denying this quiz show has earned its place in history. burt cameron still watches every night. >> doesn't everybody? >> reporter: erica hill, nbc news, new york. that's "nbc nightly news" for this sunday. brian williams will be here tomorrow. i'm lester holt, reporting from new york. for all of us here at nbc news, good night. \s good evening. i'm dine dwyer. >> and i'm terry mcsweeney. >> suspended state senator leland yee of san francisco is scheduled to make an appearance in federal court tomorrow. he's accused in an extension corruption scandal exposed after a five-year fbi sting. though the evidence appears , experts say it's far from an open and shut case. nbc's bay area monty fronsies is live in redwood city where he just spoke to a legal analyst. >> reporter: terry, good evening. most of the charges that leland yee faces have to do with public corruption. those kinds of charges are difficult to prove. leland yee's political career may well be over but the legal case against him is another