Virgin Aircraft pod strike 737 Samoa
 

A pod strike on the 23rd but not detected until the 26th after review of flight data recorder. Would one expect that to be the norm?

No not the norm preflt inspections done properly should pick up any strike damage to the lower surface of the engine.

A stab almost torn off and continued flight with pax.

A pod struck and continued flight....

Something stinks over there. JB better get some better oversight. It wouldn't be nice to be the first Australian passenger jet operator to lose one.

Poor cash flow, high levels of debt, a shrinking network, poor maintenance oversight and splashing out on sponsorship deals? I think we've been here before. With the same players too.

No wonder the kiwis are bailing.

When I check under the engines during my walk around I look at the different latch locations. I am not sure if I would pick up a scratch on the paintwork if it was between the latch locations. ( after reading this I probably will!)

You're kidding yourselves if you think you're going to reliably see anything other than proud cowl latches on a typical 737 walk.

And when was the last time you saw a 737 pilot on his hands and knees looking under the engine during a walkaround?

Perhaps the crew who were operating at the time should have been aware that something was possibly amiss after the arrival and had a better look after shutdown. Not speaking up out of fear or ridicule risks all the lives of everyone who operates and rides in that machine afterwards, until it's detected. No wants to scrape a pod, it was a genuine mistake and should be owned up to. I believe that the 'just cause' accountability protects you and when it all boils down, apart from the mishap, it's just good airmanship and integrity to own up. Keg said in another thread that we should all be looking after each other, regardless, this is just another example.

On my last walk around I spent a few minutes on the issue. The only way I could see well enough under the pod to identify damage was to get on my hands & knees. And I had to do it on both sides of the engine to cover the area completely. Not exactly practical on dirty tarmacs & in the rain, snow & ice. I guess the only other way is to lie on your back & slide under. Like you are going to do that in uniform. Either way, I don't think there is a practical way to adequately inspect the area on a walk around.


Management don't care. They just put in the manual the requirement for the pilot doing the walk around to check the cowl latches & to check for damage under the pod & provide no instruction on how to achieve that. Then they hang you for not doing so when damage goes unnoticed.


The FCTM chart shows that the flap track fairing will hit before the nacelle at pitch attitudes above 1 degree. As there is no reported flap track fairing damage, one would have to assume that the pitch attitude at touchdown was 1 degree or less. That is an awfully flat touchdown attitude. One has to think power into the flare, downslope on runway, float, push it on. Time will tell.

Oakape, that's all very well and good for pitch but what about a strike due to roll?

CC

The chart gives nacelle contact with roll from 11 degrees through to 17 degrees. So -4 degrees pitch combined with 11 degrees roll, through to +1 degree pitch combined with 17 degrees roll. This is first point of contact & the pod may have hit after the nose wheel at low pitch attitudes, but at the higher pitch attitudes the flap track fairing will hit before the pod. In fact, if the flap track fairing hits, I would be surprised if there was also a pod strike. For that to happen, there would have to be a marked decrease in pitch without any reduction in roll, unless you just happened to be right in that corner of the envelope. There had to be roll in there, but I believe the pitch also had to be very low. I have noticed a tendency over the years for 737 pilots to carry the power into the flare which leads to very flat landings - almost 3 pointers, particularly at flap 40. This may be part of the problem. Also, Boeing states that contact can occur inside the envelope due to structural flexing of the airframe. This may have been a factor here.


The wind was from the right & was gusty. Viz was reduced in heavy rain & it was at night. Remember that the cyclone was passing at that time. Depth perception can be difficult in rain on that runway at night. The runway edge lights for the first 1/4 or so of the runway are much brighter than the rest of the runway & this makes it more difficult to see & use the full runway for depth perception when the viz is bad. The runway is quite long, but is ungrooved & has a downslope. So there is some extra urgency to get the aircraft on the runway & stopped when there is heavy rain.

Oakape, nicely put.

There is quite a dip in the middle if I recall correctly, leading to the illusion that the runway is falling away then rising up to meet you.

I have not been there for years now, but when I was operating into there there was bugger all ambient lighting so it is a bit of a black hole approach just to ratchet up the difficulty level in crappy weather.

I think the concern of many would be not so much about a pod strike per se but what happened, or didn't happen, thereafter until the strike was identified some days later.

Ken, my thoughts are that based on what Oakape says here;

and the fact that I am quite diligent when inspecting under each engine on my walk arounds yet doubt that I could see a scratch between the latches, that it is very likely that pilots won't pick this up on walk arounds.
I agree that that should not be the case, but believe it is the case at the moment.
I don't have to get onto my knees to check the latches but do get right down on my haunches as low as possible and can identify all the latches from that position.I haven't done a walk around since this thread started but like Oakape will be paying special attention to whether or not I can see the entire surface.

Yeah, after thinking about it, I 'm thinking of getting one of those small inspection mirrors that are on a telescopic rod with a movable mirror.. That pod is very low on the NG... It might work, it might not, but worth a shot... If the toothpaste brigade don't take it off me or some hostie doesnt accuse me of looking up skirts with it... :O

Ken for something to happen post the landing assumes that the crew knew they had scraped the pod.

I don't think it is a given that they knew they had dragged the pod and given it was pissing down and not many people I know do post flight inspections it is not unreasonable that it wasn't immediately reported.

As for the preflight inspections, I think there has been plenty of discussion that indicates the difficulty in identifying the damage given the location so put it all together and the fact that the damage went unidentified for a few days is not surprising.

Did they suspect a hard landing had occurred at the time? If so, was it reported at the time? Surely that would have warranted a close visual inspection that should have revealed the damage to the pod.

The threshold for triggering a hard landing inspection is quite high in terms of g loading, though in many aeroplanes there are variable g limits based on roll rate etc on touchdown, so very difficult for the crews to identify if the landing they just did was actually a heavy landing.

Most reported hard landings are shown to have not exceeded that threshold, though that is usually after the fact when FOQA data is reviewed. The inspection having been done at the time in order to get the aeroplane moving again.

Again it isn't a huge surprise that a heavy landing report wasn't submitted as it needs to be a real bone crusher to actually be a heavy landing.

I am not privy to the details in this instance, nor trying to defend the actions of any party, just trying to point out that things are not as necessarily cut and dried as perhaps some people may like to believe.

Thanks Snakecharma. We've had several instances of 'firm' landings that weren't reported at the time but were subsequently determined to be 'hard' when the data was analysed. We've had it drummed into us that if there's any doubt it should written up as a hard landing and investigated accordingly. Mind you - I work for a big international airline wih engineering resources at every port, so it's relatively easy to complete the initial inspection of the aircraft. Not sure if the same applies to Virgin's operation at Apia.