Mach overspeed 737-800

[skyloone]

To use or not to use

VNAV is good at some things and franlky pretty poor at others. Now I know the saying input = output but I'd agree that its not always the smartest box of tricks. I never have understood why it'll happily dive into the clackers. For me as a rule, initially I never use VNAV when past TOD or above profile unless at a low enough altitude to have a good margin from the clackers. Even then one tends to get a dirty dive followed by a correction when at the path that results in an uncomfortable ride for all. If the situation is right use vnav but use speed intervent to limit the speed and hence the dirty dive. As mentioned in the tread before, use CWS if needs be. The slower descent may be a problem if a level restriction applies. If to be level by xyz can't be met without compromising the a/c handling say so and they'll have to negotiate another plan. ATC are not always going to realise the limitations you have to work with.

Think the company's response is less than positive. I would have hoped they would take the lessons learned and use it in the next round of training. If my memory is correct an engineering inspection is required if in the clackers for twenty seconds or more by X amount of knots. There is actually a good margin there before any damage to the wing skins is done.

Skyloone