Tuesday, March 31, 2009

Flightblogger: Remaining Milestones until First Flight

UPDATE: I got this description from Boeing:

Gauntlet tests in general are focused on integrated system integrity and functionality (hardware and software). The purpose of the factory gauntlet is to test most of the airplanes systems (not the engines or the APU) integrated on the airplane in a simulated flying environment. The intermediate and final gauntlet tests are more thorough and include engines and the APU. The engines will be run at various power settings during gauntlet testing. However, the pre-flight engine testing is a separate activity. We have not assigned specific time periods for these tests.

Jon Ostrower posted an article regarding the remaining series of tests and checkouts to be done before first flight of the 787. Jon cautions that it may not be a complete guide to the remaining work but it does give us an idea of the work yet to be done.

In short the remaining testing will utilize the static test frame (ZY997), Dreamliner 1 (ZA001) and Dreamliner 2 (ZA002).

Please read Jon's post here. I've summarize some of the salient points below.

Two of the required three static load tests have been completed on the static test frame. Te remaining test to be done is the wing load limit test.

Ground Vibration Test is to be performed on ZA002. This airplane will be towed to building 40-24 where this test will be undertaken. So far my estimate is that it will take place in the latter half of April assuming that Dreamliner 1 conducts factory gauntlet inside 40-24 on April 10th and is then towed out to the flightline on April 13th from building 40-24.

Gauntlet Testing - first is factory gauntlet which takes place indoors (presumably in 40-24) where the aircraft is getting power from an external cart and batteries. Most of the systems are powered and tested but not all. The APU and engines are not turned on here. The second is the intermediate gauntlet which takes place out on the flightline. Here the APU and the engines are started for the first time and some of the systems are run on internal power for the first time. The aircraft is fueled up for the first time here. Lastly the final gauntlet is where the aircraft systems are powered for eight days straight and put through simulations to test the software.

Final testing will comprise of three phases. First is the Hot Test where the engines are run up to 100%. There will also be engines runs at different power settings. Second is the slow and medium speed taxi tests. Lastly there will be the high speed taxi test followed by first flight.

I don't have dates yet but the last I heard is that factory gauntlet testing should start on April 10th followed by the move outside on April 13th. We'll see if this schedule keeps.


Anonymous said...

Thanks again for the increased specificity about the preflight tests for the 787.

Boeing's statement about assigning no specific time period for each test is clear, but that does not preclude the question of how long these tests USUALLY take.

For example, the factory gauntlet test is indicated in your report as taking approximately three days.

Can you speculate or guesstimate how long each one of these phases take, barring any major issues.

Another example is that the final gauntlet test involves eight days of continuous engine operation.

Your description of the final testing which involves the hot test,the taxi test and high speed taxi test does not seem to be very lengthy if all goes well.

I realize this is asking for something more specific than is ordinarily possible, but I am really asking you to give us your ideas or thoughts on the time aspect of what is involved without holding you to them.

Thank you very much for tackling this question.

Anonymous said...

Since Boeing said it will proceed to the next milestone only after the prior milestone is completed, will that expose the 787 to another delay?

Or, put another way, can the gauntlet tests go smoothly, or will there be time spent between them remedying the problems encountered in the test so that alot of time is spent in remediation that delays the completion of the series?

I think you previously answered that alot of testing has gone into this aspect alreay so it is not like starting from scratch.

Could we be surprised and the plane moves through it all quickly and without complications?

Uresh said...

AS for the length of tests, right now it's unknown. It does seem that the factory gauntlet is about 3 days and I expect that the intermediate and final gauntlet should take about a month.

There is always a chance for a delay if there is a significant issues that crops up during these gauntlet tests, what they could is something that I or even the Boeing engineers wouldn't know about.

The questions being asked is something that really can't be answered. Hopefully the systems intergration testing that took place in the systems labs have rung outmost if not all serious issues. We'll only know at the time of testing.