Ship Designer

Ship design for the quest uses the tbg-shipdesigner webapp where a class is designed from a set of chosen frames, parts, and part quantities. Previously, designers used a Google Sheets "spreadsheet app", which is now superseded because of performance issues.

Most of the designs are debated at the thread and the #shipdesignbureau discord channel.

Example ship designer webapp link of a relatively recent design: [https://to-boldly-go.github.io/tbg-shipdesigner/shipdesigner.html#%7B%22Name%22:%22%20Cheapish%20Kepler%22,%22Blueprint%20Date%22:%222017-09-23T17:31+00:00%22,%22Parts%20List%22:%7B%22name%22:%22Starfleet%20Canon%20C8%22,%22timestamp%22:%222017-10-23T06:05:42.560Z%22%7D,%22Principal%20Frame%22:%22%5BT1%5D%20900kt%20Frigate%20Frame%22,%22Module%22:%7B%22Variant%22:%22-%22,%22Type%22:%22No%20Module%22%7D,%22Subsystems%22:%5B%7B%22Name%22:%22Warp%20Core%22,%22Sub-Frame%22:%22%5BT2%5D%20Md%20Frigate%20Warp%20Core%20Suite%22,%22Settings%22:%5B%7B%22Value%22:0,%22Name%22:%22Safety/Performance%22%7D%5D,%22Components%22:%5B%7B%22Name%22:%22Warp%20Core%20Type%22,%22Quantity%22:2,%22Part%22:%22%5BT2%5D%5BL%5D%5BC+%5D%20Type-I%20Block-A%20(40E)%20Warp%20Core%22%7D,%7B%22Name%22:%22M/AM%20Injectors%22,%22Quantity%22:2,%22Part%22:%22%5BT2%5D%5BL%5D%5BR-C-%5D%20Luna-VI%20High-Efficiency%20M/AM%20System%22%7D,%7B%22Name%22:%22Coolant%20Systems%22,%22Quantity%22:2,%22Part%22:%22%5BT2%5D%5BL%5D%20Mk%20VIII%20Mod%20L%20Yoyodyne%20Coolant%20System%22%7D,%7B%22Name%22:%22EPS%20Manifold%20System%22,%22Quantity%22:3,%22Part%22:%22%5BT3%5D%5BM%5D%5BR+%5D%20VSA-7%20Pulse%20Injection%20Manifold%22%7D,%7B%22Name%22:%22Eject%20System%22,%22Quantity%22:1,%22Part%22:%22%5BT2%5D%20EngOS%20Monitoring%20-%20Anak-Krueger%20EM%20Rails%22%7D%5D%7D,%7B%22Name%22:%22Engineering%22,%22Sub-Frame%22:%22%5BT2%5D%5BOET-SR-%5D%20Md%20Frigate%20Engineering%20Suite%22,%22Settings%22:%5B%5D,%22Components%22:%5B%7B%22Name%22:%22Structural%20Integrity%20Fields%22,%22Quantity%22:2,%22Part%22:%22%5BT2%5D%5BM%5D%20Type-VI%20SIF%22%7D,%7B%22Name%22:%22Navigational%20Deflector%22,%22Quantity%22:3,%22Part%22:%22%5BT1%5D%5BL%5D%20Modulated%20Graviton%20Beam%20Deflector%20Saucer-Only%22%7D,%7B%22Name%22:%22Nacelle%20System%22,%22Quantity%22:1,%22Part%22:%22%5BT1%5D%5BL%5D%202%20X%20Centaur-A%20Pattern%20Nacelle%22%7D,%7B%22Name%22:%22Replication%20Package%22,%22Quantity%22:1,%22Part%22:%22%5BT2%5D%5BM%5D%20S-Medical%20Mk%20VI%20Protein%20Synth%22%7D,%7B%22Name%22:%22Fuel%20&%20Matter%20Stores%22,%22Quantity%22:3,%22Part%22:%22%5BT2%5D%5BL%5D%202310-Light%20Pattern%20Deuterium%20Tanks%22%7D%5D%7D,%7B%22Name%22:%22Hull%22,%22Sub-Frame%22:%22%5BT2%5D%20Sm%20Frigate%20Hull%20Suite%22,%22Settings%22:%5B%5D,%22Components%22:%5B%7B%22Name%22:%22Hull%20System%22,%22Quantity%22:1,%22Part%22:%22%5BT2%5D%5BL%5D%20Lt.%20Alloy-3%20Duranium%20Hull%22%7D%5D%7D,%7B%22Name%22:%22Operations%22,%22Sub-Frame%22:%22%5BT2%5D%5BOE--%5D%20Lg%20Frigate%20Operations%20Suite%22,%22Settings%22:%5B%7B%22Value%22:false,%22Name%22:%22Isolinear?%22%7D%5D,%22Components%22:%5B%7B%22Name%22:%22Long-Range%20Sensors%22,%22Quantity%22:2,%22Part%22:%22%5BT2%5D%5BH%5D%20Mark-VII-Heavy%20LR%20Sensor%20Array%22%7D,%7B%22Name%22:%22Navigational%20Sensors%22,%22Quantity%22:2,%22Part%22:%22%5BT2%5D%5BH%5D%20Mark-VII-Heavy%20Nav%20Array%22%7D,%7B%22Name%22:%22Survey%20Sensors%22,%22Quantity%22:0,%22Part%22:%22No%20Survey%20Sensors%22%7D,%7B%22Name%22:%22Science%20Labs%22,%22Quantity%22:2,%22Part%22:%22%5BT2%5D%5BH%5D%20Spock-C%20Pattern%20Lab%22%7D,%7B%22Name%22:%22Computer%20Core%22,%22Quantity%22:3,%22Part%22:%22%5BT1%5D%5BL%5D%20Type-III-A%20Duotronic%20Core%22%7D,%7B%22Name%22:%22Operating%20System%22,%22Quantity%22:3,%22Part%22:%22%5BT2%5D%20Majel%203.1%20OS%22%7D,%7B%22Name%22:%22Secondary%20Core%22,%22Quantity%22:0,%22Part%22:%22No%20Core%22%7D,%7B%22Name%22:%22Diplomatic%20Package%22,%22Quantity%22:2,%22Part%22:%22%5BT1%5D%5BM%5D%20Lwaxana%20'04%20General%20Protocol%22%7D,%7B%22Name%22:%22Recreation%20Package%22,%22Quantity%22:1,%22Part%22:%22%5BT-1%5D%5BM%5D%202260s%20Rec%20Space%22%7D,%7B%22Name%22:%22Sickbay%22,%22Quantity%22:3,%22Part%22:%22%5BT2%5D%5BH%5D%20T'Koren%20Pattern%20Large%20Sickbay%22%7D%5D%7D,%7B%22Name%22:%22Tactical%22,%22Sub-Frame%22:%22%5BT1%5D%5BSR+%5D%20Sm%20Frigate%20Tactical%20Suite%22,%22Settings%22:%5B%7B%22Value%22:true,%22Name%22:%22Burst%20Launchers%22%7D,%7B%22Value%22:false,%22Name%22:%22Phaser%20Arrays%22%7D%5D,%22Components%22:%5B%7B%22Name%22:%22Primary%20Phasers%22,%22Quantity%22:2,%22Part%22:%22%5BT-1%5D%5BL%5D%20Model%2068%20Phaser%20Bank%22%7D,%7B%22Name%22:%22Secondary%20Phasers%22,%22Quantity%22:0,%22Part%22:%22No%20Phasers%22%7D,%7B%22Name%22:%22Torpedo%20System%22,%22Quantity%22:0,%22Part%22:%22No%20Torp%22%7D,%7B%22Name%22:%22Short-Range%20Sensors%22,%22Quantity%22:2,%22Part%22:%22%5BT2%5D%5BH%5D%20Mark-VI-Heavy%20SR%20Lateral%20Sensor%20Array%22%7D,%7B%22Name%22:%22Targeting%20Computer%22,%22Quantity%22:1,%22Part%22:%22No%20TCU%22%7D,%7B%22Name%22:%22Deflector%20Shields%22,%22Quantity%22:5,%22Part%22:%22%5BT2%5D%5BL%5D%20Mk-V-E%20Shield%20Gens%22%7D,%7B%22Name%22:%22Backup%20Deflectors%22,%22Quantity%22:5,%22Part%22:%22%5BT2%5D%5BL%5D%20Mk-V-E%20Shield%20Gens%22%7D,%7B%22Name%22:%22Impulse%20Engine%20Pwr%22,%22Quantity%22:1,%22Part%22:%22%5BT2%5D%5BM%5D%20SDB-09%20High-Power%20Impulse%20Drive%20Sys%22%7D%5D%7D%5D%7D A Kepler design]

Parts List
The parts list of available frames/parts and their stats/costs used in the ship designer are managed in the part builder. This is primarily used to load other parts lists, typically ones that are updated with latest confirmed available parts and/or speculative parts that haven't been researched yet.

The semi-official list of speculative parts lists are curated and published by SWB after each "Ex Astris, Scientia" results update.

Official Designs
TODO: put these in the ship class articles instead and link to them from here?

Proposed Designs
See Category:Proposed Ship Designs

To publish a proposed ship design for feedback (and for archival purposes), ship designer users should create subpages under their user pages that contains, at a minimum:
 * A link to the shipdesigner for the design (or a screenshot and/or thread post for older designs)
 * at the bottom

This page can be used as a template for new proposed designs.

Ship Design Bureau Frequently Asked Questions​
With the launch of the new starship designer webapp, the Ship Design Bureau is pleased to welcome newcomers to it’s ranks. It is our hope that more players will learn ship design, either to collaborate with us in designing new vessels, or simply to gain a better understanding of the ship design system in order to vote in a more informed manner. Both Forgothrax and SynchronizedWritersBlock have collaborated to create this FAQ document to help newcomers understand the intricacies of ship design. Make no mistake, this system is very complex and has many hidden nuances. We hope that you will, after reading this document, be able to avoid common mistakes in ship design.

With no further ado!


 * 1) What does the ship designer do and not do?


 * The app designs vessels of the types we already have in service and can request as new designs. It can design frigates, cruisers, and capitals / explorers. It can’t design noncombat ships such as engineering ships, hospital ships, or freighters. It can’t design very small ships, shuttles, or fighters. It can't design foreign ships with specialty parts.


 * If you want something completely different in form from current starfleet ships, odds are it cannot suffice. But if you want to build the next Miranda, or Rennie, or Amby, look no further!


 * 2) OK, how do I start?


 * Start by choosing the size of ship you want to make. The frame determines if you are making a frigate, cruiser, or explorer, and how much weight in parts you can stuff into your ship. Then pick a subframe size for each of the five categories (tactical, operations, hull, engineering, and warp). Finally, fill each subframe with individual parts, which will add stats like science, combat, or shields. You could potentially go back and change the frame and subframes later after you know what parts you want.


 * 3) How do I install a parts list?


 * Go to Part Editor and press Load Saved Parts, then make sure to Save Current Parts. Then go into the Ship Designer and make sure to select and Load Parts List. Do NOT use Importer, Importer is not used for anything you need to worry about unless you want to import from the old spreadsheet.


 * 4) Why pick one part over another?


 * Each part has a fixed set of ship stats that it affects. For example, all sickbays have a large effect on presence and a smaller effect on science. Each part also has costs, which are usually weight, BR, SR, crew, and power. Trading off effect for weight or cost is the essential work of ship design.


 * Many of these costs are dependent on other things, which can get complex. For example, BR is dependent entirely on weight. A heavy part will cost more BR, always. SR is dependent on part weight, frame size, and part variant SR multiplier. Crew is dependent on part variant and frame size. Power is dependent on frame size, but is itself generated by parts like the warp core, which can add a hidden cost in crew, SR, or weight.


 * 5) Why pick one subframe over another?


 * Subframes don't have many costs but affect the costs of the parts inside them. They can multiply or discount SR, crew, and power costs. They have a fixed weight cost (sometimes zero), a fixed build time, and a weight limit that is derived from the subframe size multiplied by the overall frame weight limit. So a small subframe in a 300kt frame will have a tiny limit, but a small subframe in a 1800kt frame might have a more usable limit.


 * The primary cost of a subframe is build time. A crew-heavy subframe (one with lots of crew-heavy parts) can trade increased build time for lower crew cost, for example.


 * 6) What's the difference between frame sizes?


 * Frames set the overall internal weight limit and determine the class of ship is. They spend a fixed amount of weight and have a fixed build time, both these costs usually go down as tech tier increases. Internal weight limit is a multiplier that affects almost all costs, notably crew and power cost, but also SR and some BR. Therefore a larger frame will almost always increase your costs substantially.


 * It's usually best to have the smallest frame that your design parts will support. That will ensure the lowest build time and lowest crew and SR cost.


 * 7) What do these tags mean? [L] or [H]? [SR-] or [R+]?


 * We've tried to tag things that are meaningfully different between parts of the same type. For example, if you see a computer core labelled [L] for light, you can be pretty sure that it will weigh less than a computer core labelled [H] for heavy. Also, the more + or - we use, the bigger the difference between parts of the same type. Tags do not compare to parts of different types! [C+] for warp cores could mean a totally different amount of crew compared to [C+] for torpedoes.


 * The tags we use are:
 * [T0], [T1], [T-1], etc - the research tier - note that 1 and -1 are not the same; negatives represent parts older than the start-of-game
 * [L], [M], or [H] - light, medium or heavy weight - this can sometimes but not always translate to small, medium, or large effect
 * [SR] - special resources
 * [C] - crew
 * [O], [E], [T] - each individual crew category: officers, enlisted, and technicians
 * [R] - reliability


 * Balancing different sizes and variants of parts is crucial to controlling cost and getting just the right amount of effect to bump you up to a next stat for the lowest possible cost or weight.


 * 8) Why are light, medium, and heavy parts so different?


 * Very early in development, there used to be a system of light parts were intended for SR-heavy frigates, medium parts were intended for crew-heavy cruisers, and heavy parts were intended for explorers with no weight budget. That system was sidelined, but the SR vs crew vs weight tradeoff is still present in many light, medium, and heavy parts, and in frigate, cruiser, and explorer frames and subframes.


 * 9) What's the difference between T3 and T-3?


 * T-3 is tier negative three, parts three generations earlier than game start. T3 is tier three, parts three generations later than game start. Don't mix them up, there's over a century of difference!


 * 10) Should I use only the newest parts?


 * Usually, yes, but sometimes no. Sometimes old parts are "good enough" to bring you over your stat requirement but cost less in crew, SR, power, or even weight. Not every generation of parts is revolutionary, and sometimes the increased effect comes at a cost.


 * 11) What's the difference between internal and external weight limits?


 * Internal weight refers to the sum of all part weight, subframe added weight, and frame added weight. A 900kt frame will allow 900kt of internal weight. A subframe limit of 133kt will allow 133kt of internal weight in that subframe. Go over those internal limits and the ship isn't legal.


 * External weight refers to the internal weight plus nacelles and modules. Nacelles and modules are placed outside the frame and are therefore "external". External weight matters when determining what size of berth a ship will fit into.


 * 12) What's this about diminishing returns? There are 5 phaser parts on my ship. Why doesn’t it have a kickass combat stat?


 * As you add additional parts, the effect you get from each additional part reduces. The first part may give you a stat bump of 1.0, the second 0.75, the third 0.6, etc etc. Good ship design requires careful consideration of the parts necessary for specific stats. It is often wise to use multiple types of parts for the same stat instead of one type of parts alone, from an efficiency standpoint. Sometimes it is better to upsize part size for efficiency as well, although this is not always true.


 * It's worth noting there are times when more parts of one type is better than spreading the stat out even though it gives a lower effect. For example, crew tends to rise slower when adding more of the same part than when adding one of an entirely different part.


 * 13) Hull weight is weird. What's up with that?


 * That is correct. Hull part weight scales depending on the size of the total frame. This can mean that light parts weigh more than heavy ones for a large capital ship, or vice versa for a frigate. Also, SIF parts are often a better option for saving crew and weight than hull parts, particularly on smaller ships as hull parts are heavy. You cannot have more than 2 SIF per 1 hull part, but a good way to maintain efficiency is to make sure that you max out your allowed SIF before you increase your total hull parts.


 * 14) Are we penalized for lacking certain parts?


 * Yes and no. Generally speaking the app will not allow 0 in a part that is necessary for the ship to function. However, Oneiros has indicated that lacking certain non-essential parts will be penalized - the example given was that lacking recreation space would restrict ships to event response in interior sectors only. Oneiros, however, has declined to give a ruling on exactly which parts will be penalized.


 * It's best to use common sense. For example, there's no rule saying this, but a ship with no sensors at all would probably fail to fly. As a second example, there's also no rule saying this, but a ship lacking a targeting computer can likely fall back on the main computer for targeting purposes.


 * 15) My SR cost is 100.05. Why are people saying it costs 105 SR?


 * Costs round up. This means that any crew that is fractional rounds up to the next whole number (2.01 crew cost is 3 crew final cost). SR/BR depends on frame.
 * BR Cost Round - Frigate 5
 * BR Cost Round - Cruiser 10
 * BR Cost Round - Explorer 10
 * SR Cost Round - Frigate 5
 * SR Cost Round - Cruiser 5
 * SR Cost Round - Explorer 10


 * By the way, stats round down. So 3.99 science is S3, not S4.


 * 16) How do I affect evasion?


 * The biggest thing that affects evasion is frame size. A smaller ship evades better. Beyond that, the amount of D that the impulse engines add will increase evasion by a small amount.


 * What is Safety/Performance?


 * The number here trades lower reliability for increased power generation. A negative number is less safe, and generates more power. A positive number is more safe, and generates less power. This is most useful for very fine tuning. There has been discussion that reliability as a mechanic and this this safety/performance option may be phased out.


 * 17) How does warp core ejection work?


 * If the ship is destroyed or the warp core is hit, there is a percentage chance that the warp core breaches, which explodes the ship and kills the entire crew. Without an ejection system, the chance is 70%. Ejection systems decrease that chance. So if a ship with a 36% chance is destroyed, it will only blow up 36% of the time.


 * 18) What are the check boxes for parts for, such as burst launchers or phaser arrays?


 * These represent special multiplier parts. As of this time, we have unlocked burst launchers, with phaser arrays by 2325 (isolinear is still undetermined at time of writing, but likely will be available after 2330-31). These multipliers increase part costs somewhat, but greatly boost part stats. At present, we have factored multiplication into parts on the newest parts list and will be phasing out check boxes. Please avoid using them from here on out.


 * 19) My build times are hideous. How do I reduce them?


 * Frame and subframe sizes. Large subframes have hideous build times, if you can avoid using large subframes altogether your build times usually stay reasonable. If you can't, a single large subframe and as many smalls as you can tolerate is another method. This can be helped by moving stats from one subframe to another, like short-range sensors in tactical for science rather than more sensors in operations.


 * 20) My crew costs are hideous. How do I reduce them?


 * Start by reducing your frame size. If you can't, then look for large weight savings or cutting stats so you can reduce your frame size. I can't emphasize enough how important it is to consider your frame size for crew reduction.


 * Next, go through parts and trade crew-heavy parts for crew-light parts where possible. Phasers, for example, are massive crew hogs. But torpedoes, while their crew costs are not great, have automated variants. As another example, warp cores have SR+ variants, and injectors increase in crew as they go up in size while EPS systems stay the same, so you could consider swapping to SR+ warp cores and moving to light injectors but heavy EPS. Computers have variants that eliminate an entire crew type.


 * Then look at your subframes, the larger your crew cost on the subframe parts, the bigger difference changing the subframe size will make. Finally, look for exceptional parts that can be downgraded, or parts that can be eliminated entirely. For example, at the time of writing, old operating systems like the T0 Majel 2.1 cost less crew than new operating systems. Of course, this comes at a price.


 * 21) How do you design a refit?


 * Refits take an existing design, leave the frame and all subframes alone, and change the parts only. Removing a part refunds half the BR and SR, adding a part costs full BR and SR. If you change the part type, you are removing all of the old part and adding all of the new part.


 * We have some legacy designs, which were not designed with the current design system, and instead established by GM fiat. These require reworking into a base design compatible with the app before they can be refit. Look in the SDB thread for base designs, or ask other designers if they have one. If you have to make one yourself, try to get the stats exact, the technology as close as possible, crew exact, and SR as close as possible. Don't sweat BR as much, the internal/external weight system is new and disrupts the BR cost.


 * lbmaian has designed a refit mode for us in the app. Selecting another design in the second drop-down and selecting "refit for" after clicking the checkbox will provide refit costs. Changes made will be outlined in purple on the sheet.

Ship Design Tips by ​Forgothrax
Start at the top and decide what kind of ship (frigate, cruiser, capital/explorer) you want. This will influence costs and role. Following that, select the frame size you want. This influences costs as well as how much space you have to play with. As a general rule of thumb, use the smallest size and highest tier frame you can (tiers are tech level, we have most T3 and some T4 at present with a few examples of T2 hanging about).

From that, select the size of subframe for each of the 5 available (tactical, ops, Engineering, hull, warp). Size influences costs and build times. Rule of thumb to keep production time down is to use one Large frame at most and use a mix of medium and small for the rest. Bigger frames means more of a stat multiplier and usually crew or resource cost discounts. Tactical influences C and L, some S and D. Ops influences everything, but mostly S/P. Engineering influences Hull and D mostly, with a scattering of S/L from the Deflector. Hull is obvious. Warp generates power.

The rest is basically mixing and matching parts to get the stats you want. Light parts are light, but usually have higher SR and power costs. M parts have medium weight and low SR, but higher crew and power costs. H parts are heavy, but otherwise cheap in resources and crew. L parts tend to generate less stats than M than H, though not always. The more of each part you use, the less each extra one generates of a stat, so do things like use multiple kinds of sensor, or both phasers and Torpedoes. The burst launchers and phaser array parts carry multipliers and are very effective, although they are more expensive and the current gentleman's agreement over arrays is to keep C=S.

Older parts can sometimes be cheaper. Keep S = C-2 and P>1 as well as doing otherwise will incur Militarization costs. And note that stats round down and costs round up. Some breakpoints that come to mind is that T1+ phases have a massive jump in power cost compared to T0 or below, T-1 TCU and Impulse can cut crew and weight, T3 Shields are less weight efficient than T2, T1 Light Computers are massively SR cheaper than T2-3 but are a bit heavier, T2-3 Sickbays make T1 or less look awful, and Miranda Nacelles are SR cheap but power expensive.

Some other specific stuff:


 * SR sensors are expensive, but provide C and S. Use them to finalize your numbers.


 * Backup shields provide much less L than primary shields, but are significantly cheaper. Use them to fine-tune L.


 * M impulse is much better for almost all ships than H, because H impulse is extremely heavy (about a 50kt weight difference).


 * Nav sensors are more crew expensive than LR, but provide a marginal D score and same S. It's sometimes better to use one of each than to double up, because of how parts scale with number.


 * Backup computer cores are not very efficient. Be wary of them.


 * 2.1 OS is much much cheaper on the crew side than 3+. It's useful for Frigates.


 * Diplomacy is expensive. You can get a lot of your P score from Sickbays. On the same note, use 2260s Recreation or Lightweight on small ships. 2260s is very cheap on power and SR, though; Lightweight saved only 3.6kt for almost double the power requirements.


 * Hull parts are heavy. It's usually a good idea to use max SIF (you can have SIF to hull in a 2:1 ratio) before you ante up hull parts.


 * You can use Industry to fine-tune S/P as well as boost D. You'll get most of your D from Nacelles and an automatic chunk from impulse/computers, but you can usually score an extra point or two from Industry.


 * Power is pretty straightforward. We have up to T3 Warp Cores and you'll almost never want to use older ones. You either have higher Crew or SR cost with cores. EPS/Coolant/Injectors are either SR+ SR-, with SR- generating less power.

Ship Design Bureau Official Unofficial Parts Rules and guidelines (and arguments)
Various rulings, detentes and gentlesophonts agreements; alongside accumulated SDB inferences, dogma, and assumptions:


 * Phaser Arrays cap max C = S. (This is separate from the C = S + 2 overall militarisation cap, which causes some confusion). They're still really good.


 * All ships need at least two Sensors out of Short Range, Long Range, Navigational, and/or a Miranda Science (sensor) Module.


 * Modules are only available for Frigates and Cruiser frames and can't be installed on Explorers.


 * You should have at least one weapon system- all the sensors in the world won't give you an effective C score without a single Phaser bank or launcher.


 * On the other hand, one weapon system is 'enough'- e.g. Phaser Arrays often allow us to skip Torpedoes, saving weight.


 * Other parts that can be safely(?) left out- Targeting Computer, Survey Sensors, Science Labs, Secondary Core, Diplomatic Package, and a Module. Maybe secondary shields? (but they’re nearly always useful for tuning L). Note that some Roles/Profiles do require certain components (e.g. Labs for science ships).


 * Missing Parts other than the above will probably lead to the QMs deciding your design has operational restrictions, or even unforseen problems in flight.