The Flight Crew of an MD80 set 29.48 vice the actual 30.48 in their altimeters descending through FL180 into LGA. Neither the Flight Crew nor ATC noticed the error until the Captain noted the altimeters indicated below sea level while parked at the gate.
Synopsis
The Flight Crew of an MD80 set 29.48 vice the actual 30.48 in their altimeters descending through FL180 into LGA. Neither the Flight Crew nor ATC noticed the error until the Captain noted the altimeters indicated below sea level while parked at the gate.
Narrative
Descending into LGA; we received altimeter setting of 29.48. Non-flying First Officer read back same. We got lower altitudes before capturing each prior cleared altitude. We finally reached 10;000 FT; leveled off shortly before we got descents to 8;000 and then 4;000 FT. We were vectored for the ILS 22 approach; landed and taxied to the gate.After checklists were completed; the standby altimeter didn't look correct to me. Upon further observation; I realized it was reading below sea level. We checked all three altimeters against each other and all were reading the same. I then rechecked the ATIS and saw 30.48 was the setting. Unbelievable.ATC never said a word the whole descent and approach when we had to be 1;000 FT low. I'm pretty sure Center gave us the wrong altimeter setting; read back the incorrect setting and then missed it again after getting the latest ATIS. We never appeared too low; 'seat of the pants' wise. Everything was quite normal the whole descent; approach; and landing. I still can't believe everyone missed this.
Second reporter narrative
ATC appeared to have forgotten us and questioned if we were descending to cross VIBES at 13;000. We replied that MARRC at FL180 was our last clearance. ATC then cleared us to cross BEUTY at 10;000 and I read back an altimeter setting of 29.48. We set and verified the altitude and altimeter setting. The ATIS was late in updating and I wanted to get the current one.The amazing thing is that no one questioned our altimeter setting or altitude from 13;000 to the approach. Luckily; the MSA was either 2;600/2;800 for LGA. No loss of separation that we know of and no RAs or TAs sounded. We were both stunned by the serious error that had just occurred. While the Captain and I've always been very diligent about altimeter settings and updated ATIS; it never occurred to me; that an event like this could happen this way. Fortunately; it was not more serious.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.