Safety concern RWY 08 app EGAE

[mikeycollins]

I fear there may be a serious safety issue with the approach to Runway 08 at City of Derry airport.

I have just travelled on FR 613 STN - LDY and a few minutes before turning base to the approach the pilot appled a large amount of power and the aircraft went to the attitude it has when taking off. I would guess there was about 30 secs of this. The aircraft then carried out an uneventful landing.

The last time I travelled this route was 14/1/04. It was the same flight and exactly the same thing happened at about the same point (time wise..I couldn't see the ground) although the application of power was less marked.

I should point out at this stage that my personal experince of flying is that of a student PPL. However I would guess that what has happened is that the "terrain" warning has sounded. For this tio have happened twice is concerning. It would suggest errors or omissions on approach plates or perhaps in company operating manuals. It could mean poor pre landing briefing by the pilots or mistakes by ATC. Whatever it is I think it needs addressing.

How much clearance does the aircraft have when the terrain waring sounds?

[alf5071h]

Mikeycollins, a useful sharing of a potential safety issue. What was the aircraft type and do you know if GPWS or EGPWS was fitted?

Following the theme of your assumption that a terrain warning was the cause then:- If there is a specific problem with the terrain profile that could cause an unwarranted alert, and it has been identified to the GPWS manufacturers, then on larger FMS equipped aircraft the GPWS should have be desensitized.

From your description and use of the word ‘Terrain’ this implies that EGPWS was fitted. If so, and the aircraft installation / route flown was new, then unwarranted warnings could arise from database or installation problems; these should be reported to the system manufacturer.

However correct operation of the warning system should not be discounted due to many reasons including the aircraft becoming displaced from the ideal flight path. Nor should the possibility that the crew on both occasions judged that the approach was incorrect and then they ‘correctly’ decided to go-around; a perfectly normal and acceptable safety maneuver. There could be many reasons for an incorrect approach or flight path displacement – turbulence, wind shear, local met conditions, procedure design, ATC, crew; but whatever the reasons the outcome remained safe.

I hope that the operator reported the events internally and if they involved GPWS/EGPWS the reports were sent to Honeywell (or other manufacturer), who have a good record in addressing these types of problems very quickly.

To answer you question; there is no specific terrain clearance if an alert is given. The warning system uses a combination of altitude, vertical speed, aircraft configuration closure rate (time), and for EGPWS position relative to a terrain database.

[mikeycollins]

The aircraft was a 737-300. It was a Ryanair aircraft but in Buzz colours. Most Ryanair aircraft are on the Irish register but I have a feeling this aircraft was on the UK register.

The aircraft wasn't in landing phase, it was on the downwind leg. When I use terrain I must say that I didn't hear any warnings. It is only a guess from my knowledge of the local scenery.

Other than the two occasions I have mentioned in my post I have only landed on 08 once before and that was uneventful. The runway in use most of the time would be 26.

I have passed on my concern to the Irish aviation authority.

[calypso]

It would be interesting to see if anybody that flies this App regulary will care to comment.

I can say though that it can be quite difficult to guess what is happening if you are not sitting at the front. Leveling off with the gear down and siginificant flap can require a large ammount of power initially and at the back it might even feel like a climb, especially after a long iddle thrust descent. This feeling would increased by the extra G of a tight turn. Winshear might also require a large ammount of power to be applied.

[Bigscotdaddy]

Mikeycollins

I fly into Londonderry fairly regularly, thiough not in a 737.

You didn't mention whether it was a left or right base join on RWY 08 . That makes a difference.

Also, do you think the aircraft was on a visual or instrument approach? A right base approach on RWY 08 will take you over high ground which could set off a 'terrain' warning, but only on a visual approach. The NDB approach for 08 would always keep you sufficiently high to avoid warnings of that type.

Could be that what you experienced were the normal configurations for a 737 on that approach, as, in my experience, Ryanair have always operated in a very professional manner into 'Derry.

Whatever, it is very doubtful that your flight was being operated in a way to cause you concern.

[mikeycollins]

Bigscotdaddy

It was a right base approach. I don't know if it was visual or instrument. I don't think it would have been a normal landing configuration. Last wednesdays incident was quite frightening, everyone noticed whereas the earlier instance I mentioned nobody noticed.

[Eff Oh]

It does sound very much like an intermediate level off with flap and or gear down. This can result when say cleared to an altitude before intercepting the glideslope, you reach the cleared altitude before you reach the glide resulting in an "ALT CAP". The attitude has changed with flap deployment and a large amount of power is needed to keep the required speed. This is all perfectly normal and acceptable, if not really desireable, however having not flown that approach in a while it is hard to comment.

[mutt]

personal experince of flying is that of a student PPL


Ummmmmm, dont you think that this might be a case of too little knowledge of how airliners operating under IFR actually fly????


I would be very interested in knowing what response you got/get from the "department"....


Mutt.

[Captain Stable]

Sounds to me as if they were flying the DME arc to 08.

[mikeycollins]

The response I have had from the IAA is that they have noted the matter but as the aircraft was on the UK register and the airport is in the UK they asked me to refer to the CAA, which I have and their response is that the matter has been passed to the safety directorate.

I have noted some of the replies here and I can assure you that I appreciate such matters as powering up to maintain altitude before intercepting the glide slope etc, but I can assure you all that the amount of power applied and the amount of positive g rising up through my butt indicited that this wasn't the reason for the power application and also the fact that flaps hadn't been selected. I was sat just behind the wing in both cases.

I am sure, given the nature of the gently rising land in the area that there was no real prospect of hitting the ground but I don't think that these incidents should happen so frequently.