Jet Airways flights averts mid-air collision

[ross_M]

Jet Airways flights averts mid-air collision (http://timesofindia.indiatimes.com/india/Jet-Airways-flights-averts-mid-air-collision/articleshow/9312907.cms)


GUWAHATI: A Jet Airways flight with 134 passengers on board narrowly averted a mid-air collision on Thursday, triggering panic aboard, passengers said.

Jet Airways Flight No 9W 2280 from New Delhi to Guwahati was flying somewhere over Patna when it abruptly lost control, leading to chaos inside.

"First the flight abruptly turned right and then began to plummet. We thought it would crash. There was chaos and people were screaming inside," Caushik Bezboruah, chief executive officer of News Live, a satellite TV channel from Guwahati said.

"I heard people crying, some praying on top of their voices. It was a chaotic situation for close to a minute before the pilot took control," added Bhaskar Sharma, director of News Live.

Both Bezboruah and Sharma were seated in the emergency exit row of the plane.

Soon after, the pilot announced that another plane was approaching from the opposite direction and was inside the "safe zone".

"The pilot said the flight's computer system automatically navigated the plane and moved away from the path of the approaching flight to avoid a mid-air collision," Bezboruah said.

The incident took place around 11.35am. The Jet Airways flight landed safely in Guwahati around 1pm.

"No one was injured but I saw a woman with an infant frantically trying to reach her seat from the washroom when this incident took place. She didn't manage to reach her seat and instead sat on the aisle," Sharma said.

Among those aboard the plane included Assam Congress president Bhubaneswar Kalita and Congress MP Rani Narah. "God is great. We had a near brush with death," said Narah.

Jet authorities in Guwahati refused to comment on the incident saying a formal statement, if any, would be made from their head office in Mumbai.

[Graybeard]

"The pilot said the flight's computer system automatically navigated the plane and moved away from the path of the approaching flight to avoid a mid-air collision," Bezboruah said. If you lie, you gotta' be smarter than that. TCAS advises vertical maneuvers only, and at gentle rates.

[JW411]

Gentle Rates:

If my memory serves me right (and it probably doesn't) an RA requires a rate of climb or descent of 1500 fpm. If that's not enough and on receipt of an "Increase Vertical Speed" warning then 2500 fpm is required.

[ross_M]

If you lie, you gotta' be smarter than that. TCAS advises vertical maneuvers only, and at gentle rates.


Maybe he'll blame it on computer error. ;)

[Graybeard]

Right, JW, and the required acceleration to get to the advisory climb rate is gentle. It should be barely noticeable to the SLF.

[JW411]

Quite right; mind you I have seen some real overcontrolling when I have been examining in the simulator!

[eastern wiseguy]

So first of all

when it abruptly lost control

Then......

First the flight abruptly turned right and then began to plummet.

As a UK controller I expect TCAS R/A's to be in the vertical plane only is it different on the sub continent?.


"God is great. We had a near brush with death,"

But don't worry their imaginary friend had it all under control from the start.

Usual standard of journalism?

[The Fat Controller]

However, a few pilots SEEM to think that the TCAS display is their own personal RADAR display and sometimes query lateral separation :mad:

Maybe the pilot in the alleged incident decided to go for both vertical and lateral TCAS separation :=

[ross_M]

Usual standard of journalism?


For sure yes, if it is Indian journalism. I'm happy they got the flight number right at least.

[misd-agin]

Could have been an ATC directed 'turn right IMMEDIATELY!' followed by a TCAS. Had that exact scenario last month. Right turn resulted in approx. 1 mile lateral offset, RA directed climb resulted in traffic going 200' below us, Head on, FL180, 600 knot closure. Traffic climbing to above FL240 while we were descending to FL150.

Reminded me of a head on, offset BFM engagement. :ooh:

NOTAM - ATC controller training in progress

[11Fan]

I especially like the picture that accompanied the story.

[gonebutnotforgotten]

From Graybeard:

Right, JW, and the required acceleration to get to the advisory climb rate is gentle. It should be barely noticeable to the SLF.

Not quite, the assumed response for initial RA (Climb, Descend etc) is 0.25g. Not exactly pull-the-wings-off stuff perhaps, but a lot more than people should experience in normal flight (a steady 30 deg banked turn is only 0.15g), the response to an enhanced RA, Increase Climb etc, is 0.35g. So the target vertical rate should be achieved in under 5 secs.

This really matters, if you look at the Uberlingen accident report appendix 4 (http://www.bfu-web.de/cln_010/nn_53140/EN/Publications/Investigation_20Report/2002/Report__02__AX001-1-2___C3_9Cberlingen__Appendix__2-10,templateId=raw,property=publicationFile.pdf/Report_02_AX001-1-2_%C3%9Cberlingen_Appendix_2-10.pdf), you will see that the DHL 757 got nowhere near these figures, it took nearer 13 secs to get to 1500 ft/min, but if it had done it right it would probably have missed the Tu 154, despite the latter's complete foul up of its RA. For a discussion on how to achieve the target acceleration accurately (a far from trivial question that has received too little attention) see Eurocontrol ACAS Bulletin 12 (http://www.skybrary.aero/bookshelf/books/1444.pdf)

A Eurocontrol study about 10 years ago found that at the time, none of the sample RAs they studied were flown correctly (roughly half were too slow, the rest too fast); I gather more recent work suggests the figure of correct responses is now....60%, still a long way to go.

[ross_M]

I especially like the picture that accompanied the story.


Loved this comment on the article.

Simple: Once the editor knows its "Jet" airways, he decides to put a Jet engine picture. If it were Kingfisher, pic would have been a half nude gal showing beer bottle, if Spice Jet, then a gal making ad of spices, and guess what, if it were Air India, then a half nude gal having bowl in her hand, standing in front of PMO begging for money..

[Capt Turbo]

on the sub continent.

Step 1 when receiving a TA/RA: Remove all newspapers from windshield and side windows.
Step 2: Adjust your eyesight while trying to locate the threat in the sudden white light. Locate your sunglasses (on top of your head).
Step 3: Gain manual control of the aircraft after AP was inadvertently disconnected when stick pushed during newspaper removal.
Step 4: Try to figure out what the TCAS wants you to do amid all the screaming and yelling on the R/T. Increase Climb/Descent opposite to ATC orders.
Step 5: Recover from the unusual attitude.
Step 6: Praise your imaginary savior that once again (w/o any adequate action on your part) an incident did not become an accident.

When on ground: Proudly tell everyone that Indian aviation is the safest in the world - we all made it, didn´t we?

Even firm atheists will turn religious after flying some time on the sub continent. Nothing but divine intervention can explain the lack of rocketing accident rates :uhoh:

[Austrian Simon]

Preliminary investigation results indicate no loss of separation, no TCAS advisory and no wake turbulence. Enroute turbulence was encountered, no other aircraft in vicinity, end of story.

[arearadar]

Whatever actually happened, what an extraordinary way of reporting it !

[OutsideCAS]

"India.......Incredible India"

[JW411]

Well, the word we used was "smoothly".

[A7700]

Does the first thing to do when receving an RA is to disconect the auto-pilot ? and not let "the computer" do the maneuver ?

[heavy.airbourne]

A7700: AFAIK the only A/P able to fly the RA is in the A380.

[IndAir967]

MUMBAI: With reference to erroneous media reports about the aversion of a ‘mid-air collision’, Jet Airways would like to clarify that flight 9W 2280 from Delhi to Guwahati- Agartala, of July 21, 2011, for a few seconds experienced 'wake turbulence' during the cruise phase possibly on account of a Boeing 747 aircraft passing overhead in the opposite direction.

The minimum required vertical separation (1000 feet) for crossing traffic was maintained at all times.

The Jet Airways flight was completed uneventfully, landing in Guwahati at 1300 hours.

The airline regrets any inconvenience caused to its guests.

[ross_M]

Jet Airways would like to clarify that flight 9W 2280 from Delhi to Guwahati- Agartala, of July 21, 2011, for a few seconds experienced 'wake turbulence' during the cruise phase

Thought wake turbulence was a arrival / departure issue. Is it likely during Cruise?

[HEATHROW DIRECTOR]

It sure is.....

[arearadar]

As an area radar controller I received occasional reports from aircraft experiencing wake turbulence, usually when flying 1,000 feet below an opposite direction `heavy`.

One particular incident, although not wake tubulence, occured when an Air France Concord(e) at M1.5 accelerating, passed 7,000 feet above a Saudia 747 ( min vert separation required 4,000 feet ). I told the Saudia that he may experiece momentary fluctuations on his pressure instruments. The turbulance was so severe that a passenger sustained injury.

Dave